Connecting an external application

Your applications and drivers use connection strings to make a connection to IBM Cloud® Databases for Redis. The service provides connection strings specifically for drivers and applications. Connection strings are displayed in the Endpoints panel of your deployment's Overview, and can also be retrieved from the Cloud Databases CLI plug-in, and the Cloud Databases API.

Connection Strings for Applications

The information a driver needs to make a connection to your deployment is in the "redis" section of your connection strings. The table contains a breakdown for reference.

Table 1. redis/URI connection information
Field Name	Index	Description
`Type`		Type of connection - for Redis, it is "URI"
`Scheme`		Scheme for a URI - for Redis, it is "rediss"
`Path`		Path for a URI - for Redis, it is the database number
`Authentication`	`Username`	The username that you use to connect.
`Authentication`	`Password`	A password for the user - might be shown as `$PASSWORD`
`Authentication`	`Method`	How authentication takes place; "direct" authentication is handled by the driver.
`Hosts`	`0...`	A hostname and port to connect to
`Composed`	`0...`	A URI combining Scheme, Authentication, Host, and Path
`Certificate`	`Name`	The allocated name for the self-signed certificate for database deployment
`Certificate`	Base64	A base64 encoded version of the certificate.

0... indicates that there might be one or more of these entries in an array.

Redis drivers are often able to make a connection to your deployment when given the URI-formatted connection string found in the "composed" field of the connection information. For example, if you set the connection string in the environment variable REDIS_URL

export REDIS_URL=rediss://admin:$PASSWORD@e6b2c3f8-54a6-439e-8d8a-aa6c4a78df49.8f7bfd8f3faa4218aec56e069eb46187.databases.appdomain.cloud:32371/0

then the Node.js client is able to make a connection with

let connectionString = process.env.REDIS_URL;

if (connectionString === undefined) {  
  console.error("Please set the REDIS_URL environment variable");
  process.exit(1);
}

let client = null;

client = redis.createClient(connectionString, {
  tls: { servername: new URL(connectionString).hostname }
});

Alternatively, the connection string can be parsed and its parts sent to the connection handler, as with the following Python client example:

parsed = urlparse(connection_string)

r = redis.StrictRedis(
    host=parsed.hostname,
    port=parsed.port,
    password=parsed.password,
    ssl=True,
    ssl_ca_certs='/etc/ssl/certs/ca-certificates.crt',
    decode_responses=True)

Redis has an array of clients for applications to use. A fairly comprehensive list is maintained on the Redis site. Some useful things to keep in mind when choosing a client are features that allow you to easily design your application for the cloud, like configuring high-availability, security, and self-signed certificate support.

TLS and self-signed certificate support

All connections to Databases for Redis are TLS 1.2 enabled, so the driver you use to connect need to be able to support TLS encryption.

If your driver does not support the rediss: protocol or TLS/SSL connections, it is still possible to tunnel connections to the Redis database endpoint by using a TLS/SSL tunnel application such as Stunnel. An example of using Stunnel can be found on the Connecting with a Command-line Client page, where it is used to connect the redis-cli application.

Deployments also come with a self-signed certificate so you can verify the server upon starting a connection. While not required, it is an additional security step that is recommended if your client supports it.

For more information, see Cloud Databases Certificates FAQ.

Using the self-signed certificate

Copy the certificate information from the Endpoints panel or the Base64 field of the connection information.
If needed, decode the Base64 string into text.
Save the certificate to a file. (You can use the Name that is provided or your own file name).
Provide the path to the certificate to the driver or client.

CLI plug-in support for the self-signed certificate

You can display the decoded certificate for your deployment with the CLI plug-in with a command like:

ibmcloud cdb deployment-cacert <SERVICE_NAME>

This command decodes the Base64 into text. Copy and save the command's output to a file and provide the file's path to the client.