Using the Config API with Redis for Tanzu Application Service

This topic tells you how to use the Config API feature for Redis for VMware Tanzu Application Service on-demand service instances.

Config API adds an endpoint to service instances for querying Redis configuration parameters. An HTTP GET request to SERVICE-INSTANCE-BOSH-URL:8080/config/CONFIG-PARAMETER-NAME returns the value of a setting.

Prerequisites

Before you can use the Config API, you must select the Enable Config API check box in the Redis for Tanzu Application Service tile. See Configure On-Demand Service settings.

Use the Config API to query Redis configuration parameters

After enabled, the Config API is available at port 8080 on the Redis service instance. You can query it from a Cloud Foundry app.

To query Redis configuration parameters:

1. Get the hostname of the service instance by running:

   cf env APP-NAME
   

   For example:

   $ cf env redis-example-app
   
   Getting env variables for app redis-example-app in org system / space pivotal-services as admin...
   OK
   
   System-Provided:
   {
   "VCAP_SERVICES": {
     "p.redis": [
        {
           "binding_guid": "1d93f665-bb9e-493d-9c23-ea577f22a6d1",
           "binding_name": null,
           "credentials": {
              "host": "q-s0.redis-instance.pictonblue-services-subnet.service-instance-30708f54-d8be-45f7-80a6-e587337233aa.bosh", "password": "5ft5I2aXZE7eXS1gjEB5DS7Izz859d",
              "port": 6379,
              "tls_port": 16379,
              "tls_versions": [
                 "tlsv1.2",
                 "tlsv1.3"
              ]
           },
        ...
        }
     ]
   }
   

2. Query the Redis configuration parameter by running:

   cf ssh APP-NAME -c "curl HOST-NAME:8080/config/CONFIG-PARAMETER-NAME" 2>/dev/null
   

   Where: - APP-NAME - HOST-NAME - CONFIG-PARAMETER-NAME

   For example:

   $ cf ssh redis-example-app \
     -c "curl q-s0.redis-instance.pictonblue-services-subnet.service-instance-30708f54-d8be-45f7-80a6-e587337233aa.bosh:8080/config/port" 2>/dev/null
   
   6379
   

Parameters you can query

You can query any parameters except for credentials such as requirepass, masterauth, or masteruser. The following are some configuration parameters you can query.

Redis properties

You can query the following Redis properties:

• daemonize
• port

Logging

You can query the following logging parameters:

• logfile
• syslog-enabled
• syslog-facility
• syslog-ident

Persistence

You can query the following persistence parameters:

• appendfilename
• appendonly
• dbfilename
• dir

Arbitrary parameters

You can query the following arbitrary parameters:

• maxmemory-policy
• slowlog-log-slower-than
• slowlog-max-len

Plan properties

You can query the following plan properties:

• maxclients
• tcp-keepalive
• timeout