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Author's profile photo Jhodel Cailan
Jhodel Cailan
Posted on May 27, 2020 6 minute read

CAP: Consume External Service – Part 2

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19 Likes 6,746 Views 55 Comments

In my previous blog post Consume External Service – Part 1, I have tested the application using mock and real data. Just by configuring the NorthWind OData service URL in the credentials.url property, I was able to connect to the external service. This approach is only applicable for local development testing. If you try to deploy this into SCP Cloud Foundry, you will encounter an error stating that this approach is not valid for production use.

The reason behind this is that external service consumption in this CDS framework is meant to use the Destination Service in Cloud Foundry. And this is the topic of this blog — deploying the Node.js project into SCP Cloud Foundry using Destination Service.

 

 

Prerequisites

 

Blog Post Series

 

Setup Destination Configuration

First of all, why do we need to setup a destination? A simple explanation is that it is best practice to avoid hard coding the external services that you use in your application inside your code. It is better for it to be configured separately from your application because as you deploy your application into different environment like DEV, QA, or PROD, you can have a different setup of the destination per environment. Also, it keeps the sensitive information like credentials outside of your code.

  • 1. Create a Destination Service Instance in Cloud Foundry

Service Name: demo-destination
Plan: lite
  • 2. Configure a new destination

You can also test the connection if the destination can be reached. A successful test will yield a message like the one below:

Connection to "NorthWind" established. Response returned: "307: Temporary Redirect"

That’s it! We have completed the setup of our destination.

 

Deploy the application to SCP Cloud Foundry

Now let’s go back to our Node.js project — if you were able to follow through my previous blog post, then your project will look exactly like the one I have below:

https://github.com/jcailan/azure-devops/tree/cap-es-part1

The next step is to prepare the application for deployment to SCP Cloud Foundry.

  • 1. Generate the mta.yaml file using the command below:
> cds add mta

  • 2. Generate security descriptor file xs-security.json using the command below:
> cds compile srv/ --to xsuaa > xs-security.json

For our case, we can ignore the warning shown in the terminal.

  • 3. Update mta.yaml file with declaration of xsuaa and destination resources and then binding it to our node module demo-srv.
modules:
 # --------------------- SERVER MODULE ------------------------
 - name: demo-srv
 # ------------------------------------------------------------
   type: nodejs
   path: gen/srv
   properties:
     EXIT: 1  # required by deploy.js task to terminate 
   requires:
     - name: demo-destination
     - name: demo-uaa


resources:
 - name: demo-destination
   type: org.cloudfoundry.existing-service
   parameters:
     service-name: demo-destination

 - name: demo-uaa
   type: org.cloudfoundry.managed-service
   parameters:
     path: ./xs-security.json
     service: xsuaa
     service-plan: application

Note that in order for the destination service consumption to work, an xsuaa service is required to be bound to our application.

  • 4. Update the package.json cds configurations to use the NorthWind destination we have configured in SCP Cloud Foundry:
	"cds": {
		"requires": {
			"NorthWind": {
				"kind": "odata",
				"model": "srv/external/NorthWind",
				"credentials": {
					"destination": "NorthWind"
				}
			}
		}
	}
  • 5. Build the MTA Project by using the command:
> mbt build

Make sure you have saved all the files changes we did before doing the build.

An MTA archive file will be generated in the mta_archives folder.

  • 6. Deploy the MTA archive file into SCP Cloud Foundry using the command:
> cf deploy mta_archives/demo_1.0.0.mtar
  • 7. Once the deployment has completed, look out for the terminal logs which states the URL of your demo-srv module. In my case, here’s the generated URL:
s0017687913trial-dev-demo-srv.cfapps.eu10.hana.ondemand.com

 

Test the deployed Node.js app service

  • 1. Open the URL we got from the previous step using your favourite  browser, the initial page will show, and now click on the Products entity. You should see the result below:

As you can see, it is very easy to deploy the app and use the destination service. We don’t really need to do any additional JavaScript coding, all that we did is just do a little bit of configuration.

 

Testing the Node.js app locally

Now that we have deployed our application into SCP Cloud Foundry, we don’t really need to change the configuration back to a hardcoded external service URL just to test the app locally. We can test the app locally while still using the destination service in SCP Cloud Foundry. In order to be able to test locally, we need to capture the environment variable assigned to our Node.js module in SCP.

  • 1. Get the VCAP_SERVICES environment variable settings for demo-srv module

Sample data structure to capture:

{
	"VCAP_SERVICES": {
		"xsuaa": [
			{
				"label": "xsuaa",
				"provider": null,
				"plan": "application",
				"name": "demo-uaa",
				"tags": [
					"xsuaa"
				],
				"instance_name": "demo-uaa",
				"binding_name": null,
				"credentials": {
					"tenantmode": "dedicated",
					"sburl": "https://internal-xsuaa.authentication.eu10.hana.ondemand.com",
					"clientid": "<<clientid>>",
					"xsappname": "demo!t48303",
					"clientsecret": "<<clientsecret>>",
					"url": "https://myaccount.authentication.eu10.hana.ondemand.com",
					"uaadomain": "authentication.eu10.hana.ondemand.com",
					"verificationkey": "<<key>>",
					"apiurl": "https://api.authentication.eu10.hana.ondemand.com",
					"identityzone": "myaccount",
					"identityzoneid": "3779d905-0123-45f2-a66d-e5c3a78cb1c4",
					"tenantid": "3779d905-0123-45f2-a66d-e5c3a78cb1c4"
				},
				"syslog_drain_url": null,
				"volume_mounts": []
			}
		],
		"destination": [
			{
				"label": "destination",
				"provider": null,
				"plan": "lite",
				"name": "demo-destination",
				"tags": [
					"destination",
					"conn",
					"connsvc"
				],
				"instance_name": "demo-destination",
				"binding_name": null,
				"credentials": {
					"uaadomain": "authentication.eu10.hana.ondemand.com",
					"tenantmode": "dedicated",
					"clientid": "<<clientid>>",
					"instanceid": "a82d0b2d-0119-4c09-97ee-46793ad8dba2",
					"verificationkey": "<<keyu>>",
					"xsappname": "clonea82d0b2d01194c0997ee46793ad8dba2!b48303|destination-xsappname!b404",
					"identityzone": "myaccount",
					"clientsecret": "<<clientsecret>>",
					"tenantid": "3779d905-0123-45f2-a66d-e5c3a78cb1c4",
					"uri": "https://destination-configuration.cfapps.eu10.hana.ondemand.com",
					"url": "https://myaccount.authentication.eu10.hana.ondemand.com"
				},
				"syslog_drain_url": null,
				"volume_mounts": []
			}
		]
	}
}

Note that the information contained in VCAP_SERVICES environment variable have credential information and shouldn’t committed in your git repository.

  • 2. Create a file called default-env.json in the root of your project directory, and paste here the data you captured from SCP. If you are using the cds template project using the command cds init, then it has generated a .gitignore file that will automatically ignore default-env.json file we are creating here.
  • 3. Next thing to do is start the app locally using the command:
> cds watch
  • 4. Test the app on a browser by using the URL below:
http://localhost:4004/catalog/Products

As you can see we now can test the app locally using real data while also using the destination service of SCP Cloud Foundry.

If by any chance you still want to revert to testing the app using our mock data, you can still do so, you just need to amend the cds configuration in package.json to make the credentials section invalid. See below example:

	"cds": {
		"requires": {
			"NorthWind": {
				"kind": "odata",
				"model": "srv/external/NorthWind",
				"--credentials": {
					"destination": "NorthWind"
				}
			}
		}
	}

Save the changes and refresh your browser, then you will see the mock data is available again.

Closing

Now you know how easy it is to consume an external service using CAP Model and use Destination Service to manage the connection configuration. We also tested our application in three different ways:

  • Test the service directly in SCP Cloud Foundry
  • Test the service locally while still using SCP CF Destination Service
  • Test the service locally using mock data

Take note that mocking the data for your service is essential for automated unit testing, but this is another topic better dealt with over another blog.

UPDATE:

Taking this project further into — Unit Testing using Mocha and Chai

 

~~~~~~~~~~~~~~~~

Appreciate it if you have any comments, suggestions, or questions. Cheers!~

 

Assigned tags

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      • Author's profile photo Roc Antonio
        Roc Antonio

        Hi Jhodel, Im having troubles making the call to the destination it always prints a 500 erro with a 400 status code in the message. Also it says about not finding a proccess env called HTTPS_PROXY and then it fails the service run.

        Don't know whats happening, and I followed your blog perfectly.

        Thanks Jhodel Cailan

        /
      • Author's profile photo Luis Guillermo León Guzmán
        Luis Guillermo León Guzmán

        Hi Jhodel,

        Very useful post, I followed your steps and works fine, but now I want to replay this for a S/4HANA  service, but I always get this error:

        {"message":"Attempting to retrieve destination from environment variable.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.076Z","msg":"Attempting to retrieve destination from environment variable.","written_ts":1591723502076,"written_at":"2020-06-09T17:25:02.076Z"}
{"message":"Could not retrieve destination from environment variable.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.078Z","msg":"Could not retrieve destination from environment variable.","written_ts":1591723502078,"written_at":"2020-06-09T17:25:02.078Z"}
{"message":"Attempting to retrieve destination from service binding.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.078Z","msg":"Attempting to retrieve destination from service binding.","written_ts":1591723502078,"written_at":"2020-06-09T17:25:02.078Z"}
{"message":"Unable to find a service binding for given name \"SCP-TO-DEVVIRTUALNEO\"! Found the following bindings: s4cap-s4cap-uaa-S0019246072-workspKL8pDH6LAjq+PI9x, s4cap-conns4cap-S0019246072-workspOeKcqQC3TvHCyLFe, s4cap-s4cap-db-hdi-container-S0019dJBJdRo5DnLNI72P, s4cap-dests4cap-S0019246072-worksp6fvZ7pO3i0qk1mEo.\n ","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.079Z","msg":"Unable to find a service binding for given name \"SCP-TO-DEVVIRTUALNEO\"! Found the following bindings: s4cap-s4cap-uaa-S0019246072-workspKL8pDH6LAjq+PI9x, s4cap-conns4cap-S0019246072-workspOeKcqQC3TvHCyLFe, s4cap-s4cap-db-hdi-container-S0019dJBJdRo5DnLNI72P, s4cap-dests4cap-S0019246072-worksp6fvZ7pO3i0qk1mEo.\n ","written_ts":1591723502079,"written_at":"2020-06-09T17:25:02.079Z"}
{"message":"Could not retrieve destination from service binding.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.079Z","msg":"Could not retrieve destination from service binding.","written_ts":1591723502079,"written_at":"2020-06-09T17:25:02.079Z"}
{"message":"If you are not using SAP Extension Factory, this information probably does not concern you.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.079Z","msg":"If you are not using SAP Extension Factory, this information probably does not concern you.","written_ts":1591723502079,"written_at":"2020-06-09T17:25:02.079Z"}
{"message":"Attempting to retrieve destination from destination service.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.080Z","msg":"Attempting to retrieve destination from destination service.","written_ts":1591723502080,"written_at":"2020-06-09T17:25:02.080Z"}
{"message":"Unable to match a specific XSUAA service instance to the given JWT. The following XSUAA instances are bound: s4cap-SCPCFQAS91f91a19-69fd-4fcc-95de-a14f3e41a809!t4787. The following one will be selected: s4cap-SCPCFQAS91f91a19-69fd-4fcc-95de-a14f3e41a809!t4787. This might produce errors in other parts of the system!","level":"warn","custom_fields":{"package":"core","messageContext":"environment-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.081Z","msg":"Unable to match a specific XSUAA service instance to the given JWT. The following XSUAA instances are bound: s4cap-SCPCFQAS91f91a19-69fd-4fcc-95de-a14f3e41a809!t4787. The following one will be selected: s4cap-SCPCFQAS91f91a19-69fd-4fcc-95de-a14f3e41a809!t4787. This might produce errors in other parts of the system!","written_ts":1591723502081,"written_at":"2020-06-09T17:25:02.081Z"}
{"message":"Sucessfully retrieved destination from destination service.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.365Z","msg":"Sucessfully retrieved destination from destination service.","written_ts":1591723502365,"written_at":"2020-06-09T17:25:02.365Z"}
{"message":"OnPrem destination proxy settings from connectivity service will be used.","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.365Z","msg":"OnPrem destination proxy settings from connectivity service will be used.","written_ts":1591723502365,"written_at":"2020-06-09T17:25:02.365Z"}
{"message":"Unable to match a specific XSUAA service instance to the given JWT. The following XSUAA instances are bound: s4cap-SCPCFQAS91f91a19-69fd-4fcc-95de-a14f3e41a809!t4787. The following one will be selected: s4cap-SCPCFQAS91f91a19-69fd-4fcc-95de-a14f3e41a809!t4787. This might produce errors in other parts of the system!","level":"warn","custom_fields":{"package":"core","messageContext":"environment-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.366Z","msg":"Unable to match a specific XSUAA service instance to the given JWT. The following XSUAA instances are bound: s4cap-SCPCFQAS91f91a19-69fd-4fcc-95de-a14f3e41a809!t4787. The following one will be selected: s4cap-SCPCFQAS91f91a19-69fd-4fcc-95de-a14f3e41a809!t4787. This might produce errors in other parts of the system!","written_ts":1591723502366,"written_at":"2020-06-09T17:25:02.366Z"}
{"message":"Unable to create \"SAP-Connectivity-Authentication\" header: no JWT found on the current request.\n Continuing without header. Connecting to on-premise systems may not be possible.","level":"warn","custom_fields":{"package":"core","messageContext":"connectivity-service"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.538Z","msg":"Unable to create \"SAP-Connectivity-Authentication\" header: no JWT found on the current request.\n Continuing without header. Connecting to on-premise systems may not be possible.","written_ts":1591723502538,"written_at":"2020-06-09T17:25:02.538Z"}
{"message":"OnPrem destination proxy settings from connectivity service will be used.","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-06-09T17:25:02.539Z","msg":"OnPrem destination proxy settings from connectivity service will be used.","written_ts":1591723502539,"written_at":"2020-06-09T17:25:02.539Z"}
[2020-06-09T17:25:02.681Z | ERROR | 1003549]: Request failed with status code 403
[2020-06-09T17:25:02.681Z | ERROR | 1003549]: Error stacktrace: Error: Request failed with status code 403 at createError (/home/vcap/app/node_modules/axios/lib/core/createError.js:16:15) at settle (/home/vcap/app/node_modules/axios/lib/core/settle.js:17:12) at IncomingMessage.handleStreamEnd (/home/vcap/app/node_modules/axios/lib/adapters/http.js:236:11) at IncomingMessage.emit (events.js:323:22) at endReadableNT (_stream_readable.js:1204:12) at processTicksAndRejections (internal/process/task_queues.js:84:21)

        This is my mta.yaml

        ID: s4cap
_schema-version: '2.1'
parameters:
  deploy_mode: html5-repo
version: 0.0.1
modules:
  - name: s4cap-approuter
    type: approuter.nodejs
    path: s4cap-approuter
    parameters:
      disk-quota: 256M
      memory: 256M
    requires:
      - name: s4cap_html5_repo_runtime
      - name: dest_s4cap
      - name: conn_s4cap
      - name: s4cap-uaa
      - name: srv_api
        group: destinations
        properties:
          forwardAuthToken: true
          name: srv_api
          url: '~{url}'
  - name: s4cap_ui_deployer
    type: com.sap.html5.application-content
    path: s4cap_ui_deployer
    requires:
      - name: s4cap_html5_repo_host
    build-parameters:
      requires:
        - name: s4capui
          artifacts:
            - './*'
          target-path: resources/s4capui
  - name: s4cap-db
    type: hdb
    path: db
    parameters:
      memory: 256M
      disk-quota: 512M
    requires:
      - name: s4cap-db-hdi-container
  - name: s4cap-srv
    type: nodejs
    path: srv
    parameters:
      memory: 512M
      disk-quota: 512M
    provides:
      - name: srv_api
        properties:
          url: '${default-url}'
    requires:
      - name: s4cap-db-hdi-container
      - name: s4cap-uaa
      - name: dest_s4cap
      - name: conn_s4cap
  - name: s4capui
    type: html5
    path: s4capui
    build-parameters:
      builder: custom
      commands:
        - npm install
        - npm run build
      supported-platforms: []
      build-result: dist
resources:
  - name: s4cap_html5_repo_runtime
    parameters:
      service-plan: app-runtime
      service: html5-apps-repo
    type: org.cloudfoundry.managed-service
  - name: s4cap_html5_repo_host
    parameters:
      service-plan: app-host
      service: html5-apps-repo
    type: org.cloudfoundry.managed-service
  - name: s4cap-db-hdi-container
    type: com.sap.xs.hdi-container
    properties:
      hdi-container-name: '${service-name}'
  - name: s4cap-uaa
    type: org.cloudfoundry.managed-service
    parameters:
      service-plan: application
      service: xsuaa
      config:
        xsappname: 's4cap-${space}'
        tenant-mode: dedicated
      path: xs-security.json
  - name: dest_s4cap
    parameters:
      service-plan: lite
      service: destination
    type: org.cloudfoundry.managed-service
  - name: conn_s4cap
    parameters:
      service-plan: lite
      service: connectivity
    type: org.cloudfoundry.managed-service

        and my package.json

        {
	"name": "s4cap-srv",
	"description": "Generated from ../package.json, do not change!",
	"version": "1.0.0",
	"dependencies": {
		"@sap/cloud-sdk-core": "^1.17.2",
		"@sap/hana-client": "^2.4.196",
		"@sap/xsenv": "^2.2.0",
		"@sap/xssec": "^2.2.5",
		"@sap/cds": "^3.34.2",
		"passport": "^0.4.1",
		"express": "^4.17.1",
		"axios": "^0.19.2",
		"moment": "^2.24.0",
		"moment-timezone": "^0.5.28",
		"execution-time": "^1.4.1",
		"hdb": "^0.17.1",
		"uuid": "^3.4.0"

	},
	"engines": {
		"node": "^10 || ^12"
	},
	"devDependencies": {},
	"scripts": {
		"postinstall": "npm dedupe && node .build.js",
		"start": "node ./node_modules/@sap/cds/bin/cds.js serve gen/csn.json",
		"watch": "nodemon -w . -i node_modules/**,.git/** -e cds -x npm run build",
		"start:express": "node --inspect express.js"
	},
	"private": true,
	"cds": {
		"requires": {
			"db": {
				"kind": "hana",
				"model": "gen/csn.json"
			},
			"uaa": {
				"kind": "xsuaa"
			},
			"Z_OD_SCP_CORE_0001_SRV": {
				"kind": "odata",
				"model": "srv/external/Z_OD_SCP_CORE_0001_SRV",
				"credentials": {
					"destination": "SCP-TO-DEVVIRTUALNEO",
					"requestTimeout": 30000
				},
				"pool": {
					"min": 1,
					"max": 10
				}
			},
			"Z_OD_SCP_VEHI_SRV": {
				"kind": "odata",
				"model": "srv/external/Z_OD_SCP_VEHI_SRV",
				"credentials": {
					"destination": "SCP-TO-DEVVIRTUALNEO",
					"requestTimeout": 30000
				},
				"pool": {
					"min": 1,
					"max": 10
				}
			},
			"ZCDS_VW_TEST_CDS": {
				"kind": "odata",
				"model": "srv/external/ZCDS_VW_TEST_CDS",
				"credentials": {
					"destination": "SCP-TO-DEVVIRTUALNEO",
					"requestTimeout": 30000
				},
				"pool": {
					"min": 1,
					"max": 10
				}
			},
			"NorthWind": {
				"kind": "odata",
				"model": "srv/external/NorthWind",
				"credentials": {
					"destination": "NorthWind",
					"requestTimeout": 30000
				},
				"pool": {
					"min": 1,
					"max": 10
				}
			}
		},
		"auth": {
			"passport": {
				"strategy": "JWT"
			}
		},
		"odata": {
			"version": "v4"
		}
	}
}

        The destination is been using without problems by other apps, but with this method using external services in CDS is not working.

        Thanks in advance

            • Author's profile photo Fadel Cazor
              Fadel Cazor

              Hi Luis,

               

              If I use the URL instead of destination it works fine, but when I use destination it don't work anymore, need to use destination because using URL is not a suitable solution for my.

              Can you share how to solve using destination please?

              Thanks

               

              {"message":"Attempting to retrieve destination from environment variable.","level
{"message":"Could not retrieve destination from environment variable.","level":"i
{"message":"Attempting to retrieve destination from service binding.","level":"in
{"message":"Unable to find a service binding for given name \"HorasHana\"! Found 
{"message":"Could not retrieve destination from service binding.","level":"info",
{"message":"If you are not using SAP Extension Factory, this information probably
{"message":"Attempting to retrieve destination from destination service.","level"
{"message":"Unable to match a specific XSUAA service instance to the given JWT. T
{"message":"Successfully retrieved destination from destination service.","level"
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found v
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found v
{"message":"Proxy settings for https are found in environment variables.","level"
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found v
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found v
{"message":"Proxy settings for https are found in environment variables.","level"
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found v
[2020-08-18T17:05:02.129Z | ERROR | 1885843]: Request failed with status code 404
[2020-08-18T17:05:02.129Z | ERROR | 1885843]: Error stacktrace: Error: Request fa
      • Author's profile photo José Rubí Braña
        José Rubí Braña

        Hi again Jhodel,

        I noticed that you cannot do expands with a remote service like this although you can do filters.

        It's just me or its the same on all people ?

        Thanks for the great post 😉

        /
        • Author's profile photo Jhodel Cailan
          Jhodel Cailan Post author

          Thanks Jose! Yes, it’s the framework issue ?. It is a limitation at the moment. If you really need this feature then you have to code it yourself — without the use of CDS fluent API.

          Cheers! Jhodel

      • Author's profile photo Karthiheyan Murugesan
        Karthiheyan Murugesan

        Thanks, Excellent Blog, worked perfectly.

        I want to expose few more entities .  I did below changes and it is not working. What should I code more ?

        using {NorthWind as external} from './external/NorthWind.csn';
        service CatalogService {
            @readonly
            entity Products as projection on external.Products {
                key ID, Name, Description, ReleaseDate, DiscontinuedDate, Rating, Price
            };
            @readonly
            entity Productdetails as projection on external.ProductDetails;
        }
        -------------
        const cds = require('@sap/cds');
        module.exports = cds.service.impl(async function() {
            const { Products,Productdetails } = this.entities;
            const service = await cds.connect.to('NorthWind');
            this.on('READ', Products, request => {
                return service.tx(request).run(request.query);
            });
            this.on('READ', Productdetails, request => {
                return service.tx(request).run(request.query);
            });
        });
        • Author's profile photo Jhodel Cailan
          Jhodel Cailan Post author

          Thanks Karthiheyan !!

          Is it not working because you got an error? or because it doesn't show any data? I checked your code and it looks fine. You should just create a file called NorthWind-ProductDetails.csv which has a similar data like below:

          ProductID;Details
          1;Details of product 1
          2;Details of product 2
          • Author's profile photo Karthiheyan Murugesan
            Karthiheyan Murugesan

            Hi,

            It is working locally. But after deploy to CF , it is giving below error,

            Request failed with status code 400  - error after clicking on Entityset in CF link.

             

            • Author's profile photo Karthiheyan Murugesan
              Karthiheyan Murugesan

              Hi ,

              It worked after specifying field names like ID,Name

                  @readonly
                  entity Suppliers as projection on external.Suppliers{
                      key ID,Name
                  };
        • Author's profile photo Jhodel Cailan
          Jhodel Cailan Post author

          Hi Lalit Goyal

          I assume that you were able to deploy it but when you are testing the service it gave you an error 500 Internal Server Error? If this is a yes, then go back to your terminal and execute below command

          > cf logs <name of the cap service>

          This will connect you to your deployed service and will see logs in real-time. Trigger again the service that is causing errors. Then analyze the logs from your terminal and see if you can find any clue.

          • Author's profile photo Lalit Goyal
            Lalit Goyal

            I am attaching the error here.

            2020-07-09T16:34:50.49+0530 [APP/PROC/WEB/0] ERR [2020-07-09T11:04:50.497Z | ERROR | 1884455]: Failed to build
            HTTP request for destination: failed to load destination!
            2020-07-09T16:34:50.49+0530 [APP/PROC/WEB/0] ERR [2020-07-09T11:04:50.497Z | ERROR | 1884455]: Error stacktrace: Error: Failed to build HTTP request for destination: failed to load destination! at Object.errorWithCause (/home/vcap/app/node_modules/@sap-cloud-sdk/util/dist/error.js:6:20) at /home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/http-client/http-client.js:143:38 at process._tickCallback (internal/process/next_tick.js:68:7) Caused by: Error: Unable to get access token for "destination" service! No service instance of type "destination" found. at Object.resolveService (/home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/scp-cf/environment-accessor.js:190:19) at Object.<anonymous> (/home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/scp-cf/token-accessor.js:73:54) at step (/home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/scp-cf/token-accessor.js:45:23)
            at Object.next (/home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/scp-cf/token-accessor.js:26:53) at /home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/scp-cf/token-accessor.js:20:71 at new Promise (<anonymous>)
            at __awaiter (/home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/scp-cf/token-accessor.js:16:12) at Object.serviceToken (/home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/scp-cf/token-accessor.js:70:12) at /home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/scp-cf/destination-accessor.js:197:59 at step (/home/vcap/app/node_modules/@sap-cloud-sdk/core/dist/scp-cf/destination-accessor.js:45:23)

      • /
        Destination%20Configuration
        • Author's profile photo Jhodel Cailan
          Jhodel Cailan Post author

          Hi Lalit Goyal

          It looks correct to me, except that the name of your destination is NorthWind_CLONING. If you named your destination like this, then you need to make sure you use this exact name on your configuration when you want to consume this destination from your CAP Model project.

          • Author's profile photo Lalit Goyal
            Lalit Goyal

            Hi Thanks Jhodel Cailan,

            I found out the issue. Well, I didn't restart the application after binding to the destination.

            After restarting the application, it worked. Maybe you can add that step too 😀

            Thanks a lot for your help!

             

            Regards,

            Lalit

            • Author's profile photo Jhodel Cailan
              Jhodel Cailan Post author

              Hi Lalit Goyal

              Glad to know that it is working fine now. There must be some steps that you did in between which requires a restart for your case. For my steps above, the destination was configured first, then build and deploy of MTA. The MTA will be the one who will bind to the service (auto-binding) and the app should be restarted afterward, hence, manual restart is not necessary.

              Well, that's how we learn, which is by doing it! 🙂

      • Author's profile photo Christian Hanusch
        Christian Hanusch

        Hello,

        I also have a problem getting this setup. Im using business application studio.

        The error I get looks like this:

        {"message":"Attempting to retrieve destination from environment variable.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:47.991Z","msg":"Attempting to retrieve destination from environment variable.","written_ts":1594907027991,"written_at":"2020-07-16T13:43:47.991Z"}
{"message":"Could not retrieve destination from environment variable.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:47.992Z","msg":"Could not retrieve destination from environment variable.","written_ts":1594907027992,"written_at":"2020-07-16T13:43:47.992Z"}
{"message":"Attempting to retrieve destination from service binding.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:47.992Z","msg":"Attempting to retrieve destination from service binding.","written_ts":1594907027992,"written_at":"2020-07-16T13:43:47.992Z"}
{"message":"Service of type destination is not supported! Consider providing your own transformation function when calling destinationForServiceBinding, like this:\n  destinationServiceForBinding(yourServiceName, { serviceBindingToDestination: yourTransformationFunction });","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:47.993Z","msg":"Service of type destination is not supported! Consider providing your own transformation function when calling destinationForServiceBinding, like this:\n  destinationServiceForBinding(yourServiceName, { serviceBindingToDestination: yourTransformationFunction });","written_ts":1594907027993,"written_at":"2020-07-16T13:43:47.993Z"}
{"message":"Could not retrieve destination from service binding.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:47.993Z","msg":"Could not retrieve destination from service binding.","written_ts":1594907027993,"written_at":"2020-07-16T13:43:47.993Z"}
{"message":"If you are not using SAP Extension Factory, this information probably does not concern you.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:47.993Z","msg":"If you are not using SAP Extension Factory, this information probably does not concern you.","written_ts":1594907027993,"written_at":"2020-07-16T13:43:47.993Z"}
{"message":"Attempting to retrieve destination from destination service.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:47.993Z","msg":"Attempting to retrieve destination from destination service.","written_ts":1594907027993,"written_at":"2020-07-16T13:43:47.993Z"}
{"message":"Unable to match a specific XSUAA service instance to the given JWT. The following XSUAA instances are bound: na-9e477645-d9fa-4701-94d2-055247d3f219!t19402. The following one will be selected: na-9e477645-d9fa-4701-94d2-055247d3f219!t19402. This might produce errors in other parts of the system!","level":"warn","custom_fields":{"package":"core","messageContext":"environment-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:47.994Z","msg":"Unable to match a specific XSUAA service instance to the given JWT. The following XSUAA instances are bound: na-9e477645-d9fa-4701-94d2-055247d3f219!t19402. The following one will be selected: na-9e477645-d9fa-4701-94d2-055247d3f219!t19402. This might produce errors in other parts of the system!","written_ts":1594907027994,"written_at":"2020-07-16T13:43:47.994Z"}
{"message":"Sucessfully retrieved destination from destination service.","level":"info","custom_fields":{"package":"core","messageContext":"destination-accessor"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:48.296Z","msg":"Sucessfully retrieved destination from destination service.","written_ts":1594907028296,"written_at":"2020-07-16T13:43:48.296Z"}
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:48.297Z","msg":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","written_ts":1594907028297,"written_at":"2020-07-16T13:43:48.297Z"}
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:48.297Z","msg":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","written_ts":1594907028297,"written_at":"2020-07-16T13:43:48.297Z"}
{"message":"Proxy settings for https are found in environment variables.","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:48.297Z","msg":"Proxy settings for https are found in environment variables.","written_ts":1594907028297,"written_at":"2020-07-16T13:43:48.297Z"}
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:48.297Z","msg":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","written_ts":1594907028297,"written_at":"2020-07-16T13:43:48.297Z"}
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:48.297Z","msg":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","written_ts":1594907028297,"written_at":"2020-07-16T13:43:48.297Z"}
{"message":"Proxy settings for https are found in environment variables.","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:48.297Z","msg":"Proxy settings for https are found in environment variables.","written_ts":1594907028297,"written_at":"2020-07-16T13:43:48.297Z"}
{"message":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-07-16T13:43:48.297Z","msg":"Try to fetch https_proxy or HTTPS_PROXY from the process env. Found value is http://127.0.0.1:8887","written_ts":1594907028297,"written_at":"2020-07-16T13:43:48.297Z"}

         

        Thats my MTA.yaml:

        _schema-version: '3.1'
ID: cmanagement
description: "Contract Management Application"
parameters:
  enable-parallel-deployments: true
version: 0.0.1


modules:

  - name: cmanagement-db
    type: hdb
    path: db
    parameters:
      memory: 256M
      disk-quota: 256M
    requires:
      - name: cmanagement-db-hdi-container

  - name: cmanagement-srv
    type: nodejs
    path: srv
    parameters:
      memory: 512M
      disk-quota: 256M
    requires:
      - name: cmanagement-db-hdi-container
      - name: my_destination_service_instance
      - name: cm_uaa


resources:
  - name: cmanagement-db-hdi-container
    type: com.sap.xs.hdi-container
    properties:
      hdi-container-name: ${service-name}

  - name: cm_uaa
    type: org.cloudfoundry.existing-service
    parameters:
       path: ./xs-security.json
       service-plan: application
       service: xsuaa

  - name: my_destination_service_instance 
    type: org.cloudfoundry.existing-service
    parameters:
       service-name: my_destination_service_instance 
       service-pan: lite
       service: destination

         

        My Apps rootfolders package.json:

        {
  "name": "cmanagement",
  "description": "Contract Management Application",
  "version": "1.4.0",
  "engines": {
    "node": "^12.16.1"
  },
  "dependencies": {
    "@sap/node-jwt": "latest",
    "@sap/cds": "^3.21.x",
    "@sap/cds-dk": "^1.8.5",
    "@sap/cds-odata-v2-adapter-proxy": "^1.4.30",
    "@sap/hana-client": "^2.4.167",
    "express": "^4.17.1",
    "hdb": "^0.17.1",
    "mbt": "^1.0.4",
    "sqlite3": "^4.1.1"
  },
  "devDependencies": {
    "axios": "^0.19.0",
    "eslint": "^6.7.2",
    "mocha": "^6.2.2",
    "nodemon": "^2.0.1"
  },
  "scripts": {
    "build": "cds build/all --clean",
    "start": "cds watch",
    "dev": "node --inspect=localhost:4014 node_modules/.bin/cds run --in-memory",
    "test": "mocha",
    "lint": "eslint .",
    "deploy:cds": "cds deploy",
    "build:mta": "cds build/all && cds deploy && mbt build -p=cf --mtar=cm.mtar",
    "deploy:cf": "npm run build:mta && cf deploy mta_archives/${npm_package_name}_${npm_package_version}.mtar"
  },
  "cds": {
    "requires": {
      "db": {
        "kind": "sqlite",
        "credentials": {
          "database": "cm.db"
        }
      },
      "API_BUSINESS_PARTNER": {
        "kind": "odata",
        "model": "srv/external/API_BUSINESS_PARTNER",
        "credentials": {
          "destination": "Q_BP",
          "requestTimeout": 30000
        }
      }
    },
    "auth": {
      "passport": {
        "strategy": "JWT"
      }
    }
  },
  "files": [
    "db",
    "srv"
  ]
}

         

        And the default-env.json:

        {
	"VCAP_SERVICES": {
		"destination": [
			{
				"label": "destination",
				"provider": null,
				"plan": "lite",
                "name": "Q_BP",
                "url": "https://placeholder-api.s4hana.ondemand.com/sap/opu/odata/sap/API_BUSINESS_PARTNER",
                "username": ...,
                "password": ...,
                
				"tags": [
					"destination",
					"conn",
					"connsvc"
				],
				"instance_name": "my_destination_service_instance",
				"binding_name": null,
				"credentials": {
					"uaadomain": "authentication.eu10.hana.ondemand.com",
					"tenantmode": "dedicated",
					"clientid": ...,
					"instanceid": ...,
					"verificationkey": ...,
					"xsappname": clone...,
					"identityzone": ...,
					"clientsecret": ...,
					"tenantid": ...,
					"uri": "https://destination-configuration.cfapps.eu10.hana.ondemand.com",
					"url": "https://placeholder-aws.authentication.eu10.hana.ondemand.com"
				},
				"syslog_drain_url": null,
				"volume_mounts": []
			}
		],
		"xsuaa": [
			{
				"label": "xsuaa",
				"provider": null,
				"plan": "application",
				"name": "cm_uaa",
				"tags": [
					"xsuaa"
				],
				"instance_name": "cm_uaa",
				"binding_name": null,
				"credentials": {
					"tenantmode": "shared",
					"sburl": "https://internal-xsuaa.authentication.eu10.hana.ondemand.com",
					"clientid": ...,
					"xsappname": ...,
					"clientsecret": ...,
					"url": "https://placeholder-aws.authentication.eu10.hana.ondemand.com",
					"uaadomain": "authentication.eu10.hana.ondemand.com",
					"verificationkey": ...,
					"apiurl": "https://api.authentication.eu10.hana.ondemand.com",
					"identityzone": "placeholder",
					"identityzoneid": ...,
					"tenantid": ...
				},
				"syslog_drain_url": null,
				"volume_mounts": []
			}
		],
		"hana": [
			{
				"label": "hana",
				"provider": null,
				"plan": "hdi-shared",
				"name": "cmanagement-db-hdi-container",
				"tags": [
					"hana",
					"database",
					"relational"
				],
				"instance_name": "cmanagement-db-hdi-container",
				"binding_name": null,
				"credentials": {
					"host": "z",
					"port": "",
					"driver": "com.sap.db.jdbc.Driver",
					"url": "...",
					"schema": "...",
					"hdi_user": "...",
					"hdi_password": "...",
					"user": "...",
					"password": "...",
					"certificate": "..."
				},
				"syslog_drain_url": null,
				"volume_mounts": []
			}
		]
	}
}

         

        The destination configuration:

         

        When accessing the entity I get this error:

        <error xmlns="http://docs.oasis-open.org/odata/ns/metadata" ml-update="aware" ml-stage="preload" ml-view="top">
<code>500</code>
<message>Request failed with status code 404</message>
</error>
        /
        • Author's profile photo Jhodel Cailan
          Jhodel Cailan Post author

          Are you testing the service locally? For local testing you should use the "url" as credentials. The configuration you have in package.json is good for SCP deployment testing.

          • Author's profile photo Christian Hanusch
            Christian Hanusch

            Hello Jhodel

            Yes, I want to test locally using "cds watch". I tried doing that, the code looks like this:

                  "API_BUSINESS_PARTNER": {
        "kind": "odata",
        "model": "srv/external/API_BUSINESS_PARTNER",
        "url": "https://placeholder-api.s4hana.ondemand.com/sap/opu/odata/sap/API_BUSINESS_PARTNER"    
      }

             

            However now upon calling the entity I get this error:

            <error xmlns="http://docs.oasis-open.org/odata/ns/metadata" ml-update="aware" ml-stage="preload" ml-view="top">
<code>501</code>
<message>The entity "API_BUSINESS_PARTNER.A_BusinessPartner" is annotated with "@sap.persistence.skip", please implement a custom handler for it.</message>
</error>
            • Author's profile photo Jhodel Cailan
              Jhodel Cailan Post author

              Maybe the error was right? You don’t have a custom handler implemented? Did you read the first part of this blog post? In part 1, I have step there to implement the custom handler .js file.

              • Author's profile photo Christian Hanusch
                Christian Hanusch

                I actually had, my cat-service-cds looks like this:

                 

                using { my.contractmanagement, sap.common } from '../db/data-model';
using { API_BUSINESS_PARTNER as ext } from './external/API_BUSINESS_PARTNER.csn';

service CatalogService {
    
    entity TreeItems as projection on contractmanagement.TreeItems;
    entity BusinessPartner @readonly as projection on ext.A_BusinessPartner;

}

                 

                The cat-service.js like this:

                        const { BusinessPartner } = this.entities;
	    const service = await cds.connect.to('API_BUSINESS_PARTNER');
        this.on('READ', BusinessPartner, request => {
            return service.tx(request).run(request.query);
        });

                 

                What I did, I just changed:

                this.on ('READ', BusinessPartner, async (req) => {
                to

                this.on('READ', BusinessPartner, request => {

                Now this error pops up:

                <error xmlns="http://docs.oasis-open.org/odata/ns/metadata" ml-update="aware" ml-stage="preload" ml-view="top">
<code>null</code>
<message>An error occurred during serialization of the entity collection. An error occurred during serialization of the entity at index #0 in the entity collection. Value of a structured property must be an object.</message>
</error>​
              • Author's profile photo Christian Hanusch
                Christian Hanusch

                If I console.log the query, I get a HTML structure returned, having this paragraph:

                        <p><strong>Note:</strong> Since your browser does notsupport JavaScript, you must press the Continuebutton once to</p>
              • Author's profile photo Jhodel Cailan
                Jhodel Cailan Post author

                It's still tough to see where the issue is. If you can share the actual project you have right now through GitHub (or any other Git versioning tools), that would be great.

      • Author's profile photo Gaurav Karkara
        Gaurav Karkara

        Hi Jhodel,

        Thanks for such wonderful posts! I was able to follow and perform all the steps. Only part i am not able to make work was correct deploy to CF.

        Though deploy is successful and when i open the link after deploy, i even see metadata. But when i click on 'Products', i get 500 internal server error. What could be the issue?

        Gaurav

        • Author's profile photo Jhodel Cailan
          Jhodel Cailan Post author

          Thanks Gaurav Karkara !

          500 internal server errors are usually brought by some problems with the implementation of the service. It's likely that you got some issues with your code, but I can't tell what is it based on the information provided.

          What you can do is go to SCP Cockpit, navigate to the applications section and open the cap service details and extract logs there to view the logs information and try to make sense of what does the error logs tell you. Usually, it will become obvious where is the error from the logs, but if that's not the case, you can share it here so that we can analyze. Cheers!

          • Author's profile photo Gaurav Karkara
            Gaurav Karkara

            Thanks Jhodel for replying.

            I have looked at the logs and find the error:

            'Unable to get access token for 'destination' service! No service instance of type 'destination' found.'

            I have followed the exact steps as you have followed and my destination instance and corresponding entries in mta.yaml seems fine.

            It doesn't look like it's because of code. It's something to do with destination instance access. Still trying to find..

            Thanks for your support.

            Gaurav

      • Author's profile photo Karthiheyan Murugesan
        Karthiheyan Murugesan

        Hi ,

        Any lead on how to use  service.tx(request).run(request.query)  for a post call to S/4 odata. 

        Exact question

        1. How to set header parameter for getting CSRF token in  [ service.tx(request).run(request.query) ] .  I want to set [X-CSRF-TOKEN : Fetch] in a GET request header so i can set back CSRF token in post call.

        Regards,

        Karthi

      • Author's profile photo Marco Moretti
        Marco Moretti

        Hi guys,

         

        is this working on webide or I should deploy to make it work? because I'm trying to access oData service but I receive

         

        {"message":"Unable to create \"SAP-Connectivity-Authentication\" header: no JWT found on the current request.\n Continuing without header. Connecting to on-premise systems may not be possible.","level":"warn","custom_fields":{"package":"core","messageContext":"connectivity-service"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-08-05T18:49:38.260Z","msg":"Unable to create \"SAP-Connectivity-Authentication\" header: no JWT found on the current request.\n Continuing without header. Connecting to on-premise systems may not be possible.","written_ts":1596653378260,"written_at":"2020-08-05T18:49:38.260Z"}
        {"message":"OnPrem destination proxy settings from connectivity service will be used.","level":"info","custom_fields":{"package":"core","messageContext":"proxy-util"},"logger":"sap-cloud-sdk-logger","timestamp":"2020-08-05T18:49:38.261Z","msg":"OnPrem destination proxy settings from connectivity service will be used.","written_ts":1596653378261,"written_at":"2020-08-05T18:49:38.261Z"}
        Error: Failed to build HTTP request for destination: failed to build headers!

        • Author's profile photo Jhodel Cailan
          Jhodel Cailan Post author

          The steps outlined in this blog post is not meant to be executed in SAP WebIDE. Read the prerequisites section for more information.

      • Author's profile photo Fadel Cazor
        Fadel Cazor

        Hi Thanks Jhodel Cailan,

        thanks a lot for this very well article, I’m tring with it since a few days ago. I'm trying to use an external Hana Odata service.

        I achieved to make it work locally both with URL and destination, but in the latter case, for it to work I had to delete the node_modules directory, another case if this directory exists I can't reach the Odata and got an 404 or 500 error. I don’t understand why that happens, I suspect that there is some incompatibility between the npm packages that are in that directory and the components in the CF, or not?

        Is there an option so that when deploying it does not take the npm packages that exist in the node_modules directory and instead uses the ones that exist in the CF?

        • Author's profile photo Klaus Kopecz
          Klaus Kopecz

          Hi

          I'm not sure why this should be the root cause of your issue, but you can avoid deploying the node_modules folder to CF in two ways:

          • if you use 'cf push', just delete the node_modules folder before pushing. The node.js buildpack on CF will then install all dependencies during staging.
          • if you use the MTA build tool 'mbt', then you can configure the module build within mta.yaml by using an 'ignore' directive for the node_modules folder. Just go to https://sap.github.io/cloud-mta-build-tool/configuration/ and check the section "Configuring module build artifacts to package into MTA archive".

          Regards

          • Author's profile photo Fadel Cazor
            Fadel Cazor

            Hi Klaus,

            thanks for your answer, you are right the command "cf push" does not generate the directory "node_modules", instead it installs the dependencies in the process, however the process fails due to the following errors:

            ERR npx: installed 4 in 1.686s
ERR command not found: cds
ERR npm ERR! code ELIFECYCLE
ERR npm ERR! errno 1
ERR npm ERR! aprhorasextras@0.0.1 start: `npx cds run`
ERR npm ERR! Exit status 1
ERR npm ERR! 
ERR npm ERR! Failed at the aprhorasextras@0.0.1 start script.
ERR npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
ERR npm ERR! A complete log of this run can be found in:
ERR npm ERR!     /home/vcap/app/.npm/_logs/2020-08-20T15_52_36_426Z-debug.log

            My package.json file is:

                {
    "name": "aprhorasextras",
    "version": "0.0.1",
    "private": true,
    "devDependencies": {
        "@sap/cds": "^4.1.7",
        "@sap/eslint-plugin-ui5-jsdocs": "2.0.x",
        "@sap/ui5-builder-webide-extension": "1.0.x",
        "@sapui5/ts-types": "1.71.x",
        "@ui5/cli": "2.2.6",
        "bestzip": "2.1.4",
        "eslint": "5.16.x",
        "express": "^4",
        "rimraf": "3.0.2"
    },
    "ui5": {
        "dependencies": [
        "@sap/ui5-builder-webide-extension"
        ]
    },
    "scripts": {
        "start": "npx cds run"
    },
    "engines": {
        "node": "^8.0.0 || ^10.0.0",
        "npm": "^6.0.0"
    },
    "cds": {
        "requires": {
        "horasextras": {
            "kind": "odata",
            "model": "srv/external/horasextras",
            "credentials": {
            "destination": "HorasHana"
            }
        }
        }
    },
    "dependencies": {
        "@sap/cds-odata-v2-adapter-proxy": "^1.4.42",
        "@sap/xsenv": "^2.2.0",
        "@sap/xssec": "^2.2.5",
        "@types/jquery": "^3",
        "express": "^4",
        "passport": "^0.4.1"
    },
    "auth": {
        "passport": {
        "strategy": "JWT"
        }
    }
    }
            • Author's profile photo Klaus Kopecz
              Klaus Kopecz

              Hi Fadel,

              I just have a vague idea what happened. Could you check in the log output of npm which npm registry is contacted to download the cds package? If it is still npm.sap.com, then this is a general issue, because cds 4 is not there. cds 4 is only available on npmjs.org. AFAIK, npm.sap.com will not be maintained anymore ...

              Regards

      • Author's profile photo Vikas Madaan
        Vikas Madaan

        When i am using destination with basic authentication then it is working fine. But when i am using destination of type OAuth2SAMLBearerAssertion then system is not able to retrieve destination.

         

        cds.connect.to(‘SF’)

        can above statement automatically pas required JWT token. Please help is very urgent.

         

        I am also getting below error:

        Unable to match a specific XSUAA service instance to the given JWT. Is this common?

         

        @Jhodel

        Can you please help here.

         

        System is able to load destination with basic authentication but destination with type OAuth2SAMLBearerAssertion it is not.

         

        Failed to build HTTP request for destination: failed to load destination!

         

        ---new update

        Looks like cds.run and related statements don't support to pass JWT token to destination. Changing all the code to axios.

         

      • Author's profile photo Sangita Purkayastha
        Sangita Purkayastha

        Hi Thanks Jhodel Cailan,

        I followed the steps mentioned in your blog to consume an external service in my project using the destinations service instance.

        I was successfully able to test the application locally, but as soon as I deploy the code to CF environment and try to access the service, I get 502 - Bad gateway error. Any idea what could be the reason for this error?

        The cds > requires section in package.json file is as follows:

          "cds": {
    "requires": {
      "MyNumberRange": {
        "kind": "odata",
        "model": "srv/external/MyNumberRange",
        "credentials": {
          "destination": "number-range-dest"
        }
      },
      "db": {
        "kind": "sql",
        "[production]": {
          "kind": "hana"
        }
      }
    }
  },

        Also the destination that was created is a shown below:

        Regards,

        Sangita Purkayastha

        /
        • Author's profile photo Jhodel Cailan
          Jhodel Cailan Post author

          Hi Sangita Purkayastha

          The error 502 is very generic. Based on the information you provided, I can suspect that there can be an issue in your connection to HANA database. I suggest to do some troubleshooting on the deployed app like catching the error in the section of your code and logging the error into the console to get more information about the 502 error.

      • Author's profile photo Carl Önnheim
        Carl Önnheim

        Hi Thanks Jhodel Cailan

        Thanks for this article, very helpful and works like a charm!

        Is it possible to reuse the external service in the local CAP model once defined? I.e. incorporate the external service built using this guide into another service which is running in the local data model.

        In essence I have this external service (business partners from my backend ERP)

        using businesspartner from './external/businesspartner.csn';

service businessPartnerService @(requires: 'authenticated-user') {
    @readonly entity BusinessPartner as projection on businesspartner.BusinessPartnerCollection;
}

        Implemented like so:

        const cds = require('@sap/cds');

module.exports = cds.service.impl(async function() {
	const { BusinessPartner, CurrentDefaultAddressInformation } = this.entities;
	const service = await cds.connect.to('businesspartner');
	this.on('READ', BusinessPartner, request => {
		return service.tx(request).run(request.query);
	});
});

        Now I want to utilize that entity from another service, basically like this:

        using { cuid } from '@sap/cds/common';
using businessPartnerService from './businesspartner-service';

service projectService @(requires: 'authenticated-user') {
    @readonly entity BusinessPartner as projection on businessPartnerService.BusinessPartner;
    entity ProjectDraft : cuid
    {
        title : String;
        customer : Association to businessPartnerService.BusinessPartner;
    }
}

        This compiles fine and publishes the services. But if I try to navigate to a BusinessPartner entity from within the "projectService" I get:

        Entity "projectService.BusinessPartner" is annotated with "@sap.persistence.skip" and cannot be served generically.

        Can you shed some light on what the intended design pattern is here? I would like to avoid duplicating the code implementing the external service (and doing that causes other issues since the cds.connect.to('service') part only returns the actual service on the first shot).

        Again, thanks for the guide and hoping for some input on this scenario.

        Regards

        //Carl