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Hybrid Testing ​

CAP enables you to run and test your CAP application using a local SQLite database and mocks to a large extent. However, you might want to test with actual cloud services at some point.

Hybrid testing capabilities help you stay in a local development environment and avoid long turnaround times of cloud deployments, by selectively connecting to services in the cloud.

Bind to Cloud Services ​

Services on Cloud Foundry ​

sh
cds bind db --to bookshop-db

Binds the service db of your local CAP application to the service instance bookshop-db, using your currently targeted Cloud Foundry space. Here, bookshop-db is a managed service of kind hana with plan hdi-shared.

cds bind automatically creates a service key for you

If no service key for your service <srv> is specified, a <srv>-key is automatically created. The service name db can be omitted as it represents the default value for the service kind hana.

Got errors? See our troubleshooting for connection issues with SAP HANA Cloud.

Output:

log
[bind] - Retrieving data from Cloud Foundry...
[bind] - Binding db to Cloud Foundry managed service bookshop-db:bookshop-db-key with kind hana.
[bind] - Saving bindings to .cdsrc-private.json in profile hybrid.
[bind] -
[bind] - TIP: Run with cloud bindings: cds watch --profile hybrid

For most commonly used services, CAP can automatically infer the service type and kind — in our example, the db CDS service is bound and set to the hana kind without additional parameters.

json
{
  "requires": {
    "[hybrid]": {
      "db": {
        "kind": "hana",
        "binding": {
          "type": "cf",
          "apiEndpoint": "https://api.sap.hana.ondemand.com",
          "org": "your-cf-org",
          "space": "your-cf-space",
          "instance": "bookshop-db",
          "key": "bookshop-db-key",
          "vcap": {
            "label": "hana",
            "plan": "hdi-shared"
          },
          "resolved": false
        }
      }
    }
  }
}

Bindings are assigned to the hybrid profile by default.

No credentials are saved on-disk

Only the information about where the credentials can be obtained is stored on your machine.

User-Provided Services on Cloud Foundry ​

sh
cds bind my --to bookshop-ups

Binds the service my of your local CAP application to the user provided service instance bookshop-ups. The service name my has to match the service name used in the CDS requires service configuration.

Output:

log
[bind] - Retrieving data from Cloud Foundry...
[bind] - Binding my to Cloud Foundry user provided service bookshop-ups. 
[bind] - Saving bindings to .cdsrc-private.json in profile hybrid.
[bind] -
[bind] - TIP: Run with cloud bindings: cds watch --profile hybrid

Shared Service Instances on Cloud Foundry since @sap/cds-dk 7.9.0 ​

On SAP BTP Cloud Foundry, service instances can be shared across orgs and spaces. Even such shared instances can be used in cds bind:

sh
cds bind messaging --to bookshop-redis

Binds the messaging service of your CAP application to the shared bookshop-redis service instance. cds bind retrieves the org and space where the service is shared from, as the service key needs to be created within that org and space. This requires the Space Developer role for both spaces.

Use cds bind --to bookshop-redis

The service name messaging can be omitted as it represents the default value for the service kind redis-messaging.

json
{
  "requires": {
    "[hybrid]": {
      "redis": {
        "binding": {
          "type": "cf",
          "apiEndpoint": "https://api.sap.hana.ondemand.com",
          "org": "shared-from-cf-org", 
          "space": "shared-from-cf-space", 
          "instance": "redis-cache",
          "key": "redis-cache-key",
          "resolved": false
        },
        "kind": "redis-messaging",
        "vcap": {
          "name": "messaging"
        }
      }
    }
  }
}

cds watch --profile hybrid will automatically resolve shared service instance bindings using the correct org and space.

Not all services can be shared

Only services that have the shareable flag in the metadata set to true can be shared. Use command cf curl /v3/service_offerings to read the service catalog metadata. See the CloudFoundry docs for further details.

Allow dynamic deploy targets

Service bindings created by cds bind contain the Cloud Foundry API endpoint, org, and space. You can allow your services to connect to the currently targeted Cloud Foundry org and space by removing these properties from the binding structure.

Services on Kubernetes ​

You can bind to Service Bindings of Open Service Broker service instances, such as SAP BTP services, on your Kubernetes cluster and to plain Kubernetes Secrets by adding the --on k8s option to the cds bind command:

sh
cds bind -2 ‹service binding or secret› --on k8s

The command uses your current Kubernetes context. That is your current server and namespace. You need to be logged in as a precondition.

Bind to Kubernetes Service Bindings ​

To list all Service Bindings in your current Kubernetes context, you can use the kubectl get servicebindings command:

log
NAME                   SERVICE-INSTANCE  SECRET-NAME           STATUS  AGE
bookshop-auth-binding  bookshop-auth     bookshop-auth-secret  Ready   11s

Use the service binding name for the -2 option:

sh
cds bind -2 bookshop-auth-binding --on k8s

Output:

log
[bind] - Retrieving data from Kubernetes...
[bind] - Binding uaa to Kubernetes service binding bookshop-auth-binding with kind xsuaa
[bind] - Saving bindings to .cdsrc-private.json in profile hybrid
[bind] -
[bind] - TIP: Run with cloud bindings: cds watch --profile hybrid

The binding information is stored in the .cdsrc-private.json file of your project in the requires section:

json
{
  "requires": {
    "[hybrid]": {
      "auth": {
        "binding": {
          "type": "k8s",
          "name": "bookshop-auth-binding",
          "cluster": "https://apiserver.d9a6204.kyma-stage.shoot.live.k8s-hana.ondemand.com",
          "instance": "bookshop-auth",
          "namespace": "dev",
          "secret": "bookshop-auth-secret",
          "resolved": false,
          "vcap": {
            "label": "xsuaa",
            "plan": "application"
          }
        },
        "kind": "xsuaa"
      }
    }
  }
}

Bind to Kubernetes Secrets ​

Alternatively, you can bind to Kubernetes Secrets.

You can use the kubectl get secrets command to list all secrets in your current Kubernetes context:

log
NAME               TYPE      DATA   AGE
bookshop-db        Opaque    11     44h

Use the secret name for the -2 option.

You need to provide either the service argument or the --kind option as well, because secrets have no service metadata.

sh
cds bind -2 bookshop-db --on k8s --kind hana

Output:

log
[bind] - Retrieving data from Kubernetes...
[bind] - Binding db to Kubernetes secret bookshop-db with kind hana
[bind] - Saving bindings to .cdsrc-private.json in profile hybrid
[bind] -
[bind] - TIP: Run with cloud bindings: cds watch --profile hybrid

Service bindings take precedence

If a service binding with the same name as the Kubernetes secret exists, cds bind will connect to the service binding instead.

Run with Service Bindings ​

Run CAP Node.js Apps with Service Bindings ​

Now, you can run your CAP service locally using the cloud service bindings:

sh
cds watch --profile hybrid

It will resolve the cloud bindings in your configuration:

  1. Bindings to Cloud Foundry: The credentials are downloaded from the service key of the Cloud Foundry API endpoint, org, and space that were targeted when cds bind was called. This requires you to be logged in to the correct Cloud Foundry API endpoint.
  2. Bindings to Kubernetes: The credentials are downloaded from the service bindings and secrets of the Kubernetes cluster and namespace that were in the current context when cds bind was called.

You can also resolve and display credentials using the cds env command:

sh
cds env get requires.db.credentials --profile hybrid --resolve-bindings

Example output:

js
{
  url: 'jdbc:sap://BDB9AC0F20CB46B494E6742047C4F99A.hana.eu10.hanacloud.ondemand.com:443?encrypt=true&validateCertificate=true&currentschema=BDB9AC0F20CB46B494E6742047C4F99A',
  host: 'bdb9ac0f20cb46b494e6742047c4f99a.hana.eu10.hanacloud.ondemand.com',
  port: '443',
  driver: 'com.sap.db.jdbc.Driver',
  schema: 'BDB9AC0F20CB46B494E6742047C4F99A',
  hdi_user: 'BDB9AC0F20CB46B494E6742047C4F99A_DT',
  hdi_password: 'abc...xyz',
  user: 'BDB9AC0F20CB46B494E6742047C4F99A_RT',
  password: 'abc....xyz',
  certificate: '-----BEGIN CERTIFICATE-----\n' +
    '...' +
    '-----END CERTIFICATE-----'
}

Run Arbitrary Commands with Service Bindings ​

With cds bind you avoid storing credentials on your hard disk. If you need to start other local applications with cloud service bindings, you can use the exec option.

For example, you can run the App Router from an approuter child directory:

sh
cds bind --exec -- npm start --prefix approuter
cmd
cds bind --exec -- npm start --prefix approuter
powershell
cds bind --exec '--' npm start --prefix approuter

This works by constructing a VCAP_SERVICES environment variable. You can output the content of this variable as follows:

sh
cds bind --exec -- node -e 'console.log(process.env.VCAP_SERVICES)'
cmd
cds bind --exec -- node -e 'console.log(process.env.VCAP_SERVICES)'
powershell
cds bind --exec '--' node -e 'console.log(process.env.VCAP_SERVICES)'

Run CAP Java Apps with Service Bindings ​

Start your CAP Java application with cds bind --exec to use remote service bindings:

sh
cds bind --exec mvn spring-boot:run

Bindings from a Cloud Application ​

Instead of binding to specific cloud services, you can bind to all supported service bindings of an application running on the SAP BTP Cloud Foundry environment:

sh
cds bind -a bookshop-srv # ...or the spelled out way:
cds bind --to-app-services bookshop-srv

This shortcut is only possible if you don't need to provide a kind.

If your application has multiple service bindings of the same kind, cds bind will log warnings since they can not be resolved automatically. In this case you can resolve the ambiguities by adding the correct service instance name to the cds service configuration using the vcap.name property.

Here is an example of adding vcap.name for services of kind xsuaa.

json
"requires": {
  "auth": {
    "kind": "xsuaa",
    "vcap": {
      "name": "bookshop-auth1"
    }
  },
  "auth2": {
    "kind": "xsuaa",
    "vcap": {
      "name": "bookshop-auth2"
    }
  }
}

cds bind Usage ​

By Cloud Service Only ​

The shortest way to use cds bind is to specify only the Cloud Foundry service instance name:

sh
cds bind -2 bookshop-db

You can specify a different key after a colon (":"):

sh
cds bind -2 bookshop-db:my-db-key

With different profile ​

By default cds bind uses the profile hybrid to store binding information. You can specify a different profile with --for or shortcut -4:

sh
cds bind --to bookshop-db --for test

You have to use the same profile name for hybrid testing to correctly resolve any bindings you've created with this profile.

sh
cds watch --profile test

With CDS Service and Kind ​

If kind or CDS service cannot be determined automatically by cds bind, you need to specify it:

sh
cds bind credstore -2 my-credstore --kind credstore

You are informed with an error message if this is required.

Bind Multiple Services with One Command ​

There is a handy shortcut to bind multiple services with one command:

sh
cds bind -2 bookshop-db,bookshop-auth

This shortcut is only possible if you don't need to specify a kind.

Overwrite Cloud Service Credentials ​

Some hybrid test scenarios might require to overwrite dedicated service credential values. For example, if you want to connect to a Cloud Foundry service via an SSH tunnel. In the example below the value of the property onpremise_proxy_host is updated with the value localhost.

sh
cds bind -2 my-service --credentials '{ "onpremise_proxy_host": "localhost" }'
json
{
  "requires": {
    "[hybrid]": {
      "my-service": {
        "binding": {
          "type": "cf",
          "apiEndpoint": "https://api.sap.hana.ondemand.com",
          "org": "your-cf-org",
          "space": "your-cf-space",
          "instance": "my-service",
          "key": "my-service-key",
          "credentials": { 
            "onpremise_proxy_host": "localhost"
          }, 
          "resolved": false
         }
      }
    }
  }
}

Now, you can run your CAP service locally using cloud service bindings in combination with merged custom credential values:

sh
cds watch --profile hybrid

Example output:

js
{
  onpremise_proxy_host: 'localhost', 
  // other cloud foundry credential values
}

You can also overwrite credential values for multiple services with a single cds bind call. Use the service instance together with an optional service key name as defined in the --to parameter to add the custom credential values for that service:

sh
cds bind --to my-service,redis-cache:my-key,bookshop-xsuaa --credentials \
  '{ "my-service": { "onpremise_proxy_host": "localhost" }, "redis-cache:my-key":{ "hostname": "localhost", "port": 1234 }}'

Use the service instance name in combination with the option --to-app-services if you want to create bindings for all service instances of your application:

sh
cds bind --to-app-services bookshop-srv --credentials \
  '{ "my-service": { "onpremise_proxy_host": "localhost" }, "redis-cache":{ "hostname": "localhost", "port": 1234 }}'

See Accessing services with SSH for further details on how you can gain direct command line access to your deployed service instance using SSH.

With Profile and Output File ​

By default, the bindings for the hybrid profile are stored in the .cdsrc-private.json file in your current working directory.

This can be overwritten using the --out option.

Execute Commands with Bindings ​

You can start arbitrary command line programs with your bindings.

The service bindings are resolved from the cloud and provided in the VCAP_SERVICES env variable to the application. So it works with every application that can consume Cloud Foundry credentials.

sh
cds bind --exec [--] <command> <args ...>

Use the double-dash (--) if your command has args starting with a dash (-) character. Otherwise the cds command line will try to parse them as their own options.

On PowerShell you need to quote the double dash (--) when an option with double dash follows:

powershell
cds bind --exec '--' somecmd --someflag --some-double-dash-parameter 42

Profiles can be set using the optional --profile parameter. By default the hybrid profile is used.

sh
cds bind --exec --profile <profile> [--] <command> <args ...>

The --profile parameter must follow exec directly.

Use Cases ​

Most of the following use cases are shown for Node.js, but can be easily adapted for Java.

Destinations ​

Learn how to connect to remote services locally using SAP BTP destinations.

Authentication and Authorization using XSUAA ​

Learn how to do hybrid testing using the XSUAA service in the CAP Node.js authentication documentation.

Integration Tests ​

cds bind can be handy for testing with real cloud services in your CI/CD pipeline.

Configure your required bindings for testing and save them to your project's package.json file for your tests' profile:

sh
cds bind -2 integration-test-hana -o package.json -4 integration-test

No credentials are saved!

In your CI/CD pipeline you can resolve the bindings and inject them into the test commands:

sh
# Login
cf auth $USER $PASSWORD
# Optional if your bindings have org and space removed to be agnostic
cf target -o $ORG -s $SPACE

# Set profile
export CDS_ENV=integration-test  

# Set resolved bindings
export cds_requires="$(cds env get requires --resolve-bindings)"

# Run tests
npm run integration-test

Some comments to the previous snippet:

  • With CDS_ENV you specify the configuration profile for the test, where you previously put the service binding configuration.
  • cds env get requires prints the requires section of the configuration as a JSON string. Through --resolve-bindings, it includes the credentials of the service bindings from the cloud. To make the credentials available for all subsequent cds commands and the tests, the requires JSON string is put into the cds_requires script variable.
  • In npm run integration-test any test code can run, for example, cds.test.

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