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environment-variables.md

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Application Service Adapter environment variables

Application Service Adapter sets environment variables when it builds and runs an application. Here's what you should know about environment variables.

Environment variables overview

Environment variables are the means by which Application Service Adapter communicates with a deployed app about its environment.

For information about setting your own app-specific environment variables, see the Environment Variable section of the Deploying with App Manifests topic.

View environment variables

Using the Cloud Foundry Command Line Interface (cf CLI), run the cf env command to view the Application Service Adapter environment variables for your app. The cf env command displays the following environment variables:

  • The user-provided variables set using the cf set-env command

For more information about the cf env command, see env in the cf CLI documentation. For more information about the cf set-env command, see set-env in the cf CLI documentation.

The following example demonstrates the environment variables cf env displays:

$ cf env my-app
Getting env variables for app my-app in org my-org / space my-space as
admin...
No system-provided env variables have been set

User-Provided:
MY_DRAIN: http://drain.example.com
MY_ENV_VARIABLE: 100

No running env variables have been set

No staging env variables have been set

App-specific system variables

This section describes the environment variables that Application Service Adapter makes available to your application container. Some of these variables are the same across instances of a single app, and some vary from instance to instance.

You can access environment variables programmatically, including variables defined by the buildpack.

The following table lists the app-specific system environment variables available to your application container. See App-Specific System Variables in TAS for VMs Environment Variables for more information about each environment variable.

Environment Variable Running Staging
CF_INSTANCE_ADDR n/a n/a
CF_INSTANCE_GUID x n/a
CF_INSTANCE_INDEX x n/a
CF_INSTANCE_INTERNAL_IP x n/a
CF_INSTANCE_IP x n/a
CF_INSTANCE_PORT n/a n/a
CF_INSTANCE_PORTS n/a n/a
CF_STACK n/a n/a
DATABASE_URL n/a n/a
HOME x n/a
INSTANCE_GUID n/a n/a
INSTANCE_INDEX n/a n/a
LANG n/a n/a
MEMORY_LIMIT n/a n/a
PATH x n/a
PORT x n/a
PWD x n/a
TMPDIR n/a n/a
USER n/a n/a
VCAP_APP_HOST x n/a
VCAP_APP_PORT x n/a
VCAP_APPLICATION x n/a
VCAP_SERVICES x n/a

CF_INSTANCE_GUID

The UUID of the app instance.

For example: CF_INSTANCE_GUID=41653aa4-3a3a-486a-4431-ef258b39f042

CF_INSTANCE_INDEX

The index number of the app instance.

For example: CF_INSTANCE_INDEX=0

CF_INSTANCE_INTERNAL_IP

The internal IP address of the container running the app instance.

For example: CF_INSTANCE_INTERNAL_IP=5.6.7.8

CF_INSTANCE_IP

The external IP address of the host running the app instance.

For example: CF_INSTANCE_IP=1.2.3.4

HOME

The root folder for the deployed app.

For example: HOME=/home/cnb

PORT

The port on which the app listens for requests. Application Service Adapter allocates a port dynamically for each instance of the app, so code that obtains or uses the app port must refer to it by using the PORT environment variable.

For example: PORT=8080

PWD

The present working directory where the buildpack that processed the app ran.

For example: PWD=/workspace

VCAP_APP_HOST

Deprecated. Always set to 0.0.0.0.

VCAP_APP_PORT

Deprecated name for the PORT variable.

VCAP_APPLICATION

Application Service Adapter provides added runtime information in the VCAP_APPLICATION environment variable. The following table lists the attributes that are returned in JSON format.

Attribute Description
application_id The GUID of the application.
application_name The name of the application.
cf_api The location of the Cloud Foundry API for the Application Service Adapter deployment where the app runs.
name The name of the application (identical to application_name).
organization_id The GUID identifying the org where the app is deployed.
organization_name The human-readable name of the org where the app is deployed.
space_id The GUID identifying the space where the app is deployed.
space_name The human-readable name of the space where the app is deployed.

The following example shows the value of the VCAP_APPLICATION environment variable:

VCAP_APPLICATION=
{
  "application_id": "6d36d101-e1ff-4a41-9bc8-c90f2cb329d3",
  "application_name": "my-application",
  "cf_api": "https://cf-api.example.com",
  "name": "my-application",
  "organization_id": "cf-org-95f15208-a6b6-4491-805c-7d46a4112343",
  "organization_name": "my-org",
  "space_id": "cf-space-28e4ede3-6399-45aa-bc4b-862040111814",
  "space_name": "my-space"
}

VCAP_SERVICES

Application Service Adapter has support for user-provided service instances and adds their binding details to the VCAP_SERVICES environment variable. For more information, see User-Provided Service Instances in the Cloud Foundry documentation.

Application Service Adapter returns the results as a JSON document that contains an object for each service for which one or more instances are bound to the app. The service object contains a child object for each instance of the service that is bound to the app.

The following table defines the attributes that describe a bound service. The key for each service in the JSON document is the same as the value of the label attribute.

Note Application Service Adapter does not support managed services, so the label for a user-provided service instance is always user-provided. VMware recommends that apps find connection details through the user-settable tags field when parsing VCAP_SERVICES. Although Application Service Adapter does not support managed services, a user-provided service can be used to supply similar credentials. In this case, existing application code or libraries might expect the credentials to have a specific label value. To accommodate these apps, you can specify the label of a user-provided service instance by setting the spec.serviceLabel field on its associated CFServiceInstance custom resource by using the Kubernetes command line tool (kubectl CLI).

Attribute Description
binding_guid The GUID of the service binding.
binding_name The name assigned to the service binding by the user.
instance_guid The GUID of the service instance.
instance_name The name assigned to the service instance by the user.
name The binding_name, if it exists. Otherwise, the instance_name.
label The name of the service offering.
tags An array of strings an app can use to identify a service instance.
credentials A JSON object containing the service-specific credentials needed to access the service instance.
syslog_drain_url Not supported.
volume_mounts Not supported.

The following example shows the value of the VCAP_SERVICES environment variable for bound user-provided service instances.

VCAP_SERVICES=
{
  "custom-service-label": [
    {
      "binding_guid": "5ef8a506-9c64-4a84-8901-7bb942da8660",
      "binding_name": null,
      "credentials": {
        "sample-config": "sample-value",
        "type": "user-provided"
      },
      "instance_guid": "3b5d58b4-cab3-4b47-b1fa-db204e54fa59",
      "instance_name": "custom-labeled-service",
      "label": "custom-service-label",
      "name": "custom-labeled-service",
      "syslog_drain_url": null,
      "tags": [],
      "volume_mounts": []
    }
  ],
  "user-provided": [
    {
      "binding_guid": "65ec345e-4f19-4499-ae70-a32b55c7f1cf",
      "binding_name": null,
      "credentials": {
        "hostname": "ca6efe83-8a9b-4395-98d0-124145d4e97a.mysql.service.internal",
        "jdbcUrl": "jdbc:mysql://ca6efe83-8a9b-4395-98d0-124145d4e97a.mysql.service.internal:3306/service_instance_db?user=441123dedf5d4b7ab988d7fae43bc452&password=P4$$W0RD&useSSL=false",
        "name": "service_instance_db",
        "password": "P4$$W0RD",
        "port": "3306",
        "type": "user-provided",
        "uri": "mysql://441123dedf5d4b7ab988d7fae43bc452:P4$$W0RD@ca6efe83-8a9b-4395-98d0-124145d4e97a.mysql.service.internal:3306/service_instance_db?reconnect=true",
        "username": "441123dedf5d4b7ab988d7fae43bc452"
      },
      "instance_guid": "0622de7e-2437-4a39-8048-a7df324c35df",
      "instance_name": "mysql",
      "label": "user-provided",
      "name": "mysql",
      "syslog_drain_url": null,
      "tags": [
        "p.mysql",
        "mysql",
        "database"
      ],
      "volume_mounts": []
    },
    {
      "binding_guid": "be7aba4d-a465-4e9d-9c01-9ce9861e68e7",
      "binding_name": "custom-binding-name",
      "credentials": {
        "some-credential": "some-value",
        "type": "user-provided"
      },
      "instance_guid": "f97f96d7-62f2-43db-866a-175f5a8e95bc",
      "instance_name": "custom-user-provided-service",
      "label": "user-provided",
      "name": "custom-binding-name",
      "syslog_drain_url": null,
      "tags": [
        "user-defined",
        "arbitrary",
        "tags"
      ],
      "volume_mounts": []
    }
  ]
}