Service Binding should follow standard CAP behaviour

[gregorwolf]

Hello Event Queue Team,

the SAP BTP redis service can only be reached via an SSH tunnel (see: Access a Redis-cache Instance from Redis-cli). Because of that Hybrid Testing is not directly possible. I've solved this by creating a User Provided Service named redis-cache with the following data:

{
    "credentials": {
        "hostname": "127.0.0.1",
        "port": 6379,
        "uri": "redis://127.0.0.1:6379",
        "cluster_mode": false
    }
}

This UPS can be bound to the local CAP environment using:

cds bind redis-cache --to redis-cache

with this adjustment of redisCredentialsFromEnv() that uses @sap/xsenv instead of a hard read for redis-cache in VCAP_SERVICES I was then able to connect to a local redis running in a container:

docker run -p 6379:6379 --name redis-cache -d redis

I would think that the plugin should be improved to follow the CAP best practice for Service Bindings. Maybe @chgeo or @oklemenz can give some guidance about the best way for the service binding.

Best Regards
Gregor

[soccermax]

Hi @gregorwolf,

thanks for reporting this. Yes hybrid testing with cds bind should be supported. I'll provide a fix.

Best regards,
Max

[soccermax]

@gregorwolf can you lock at the attached PR? Would that work for you?
As long as your binding hybrid or not has the label redis-cache it should work. You can even redefine the vcap section of cds.requires["eventqueue-redis-cache"]. But I think for most use cases this should not be needed.
I prefer to rely on the CAP implementation of reading service credentials over the use of xssev.

[gregorwolf]

Hi @soccermax,

thank you for the quick fix. This works great when providing redis local via a docker container. But as the SAP BTP redis service can only be reached via an SSH tunnel (see: Access a Redis-cache Instance from Redis-cli) and also requires TLS it would be great if you can provide an option to set the TLS options. My workaround for the moment is to add an entry for the BTP redis service hostname in my local hosts file and point to localhost.

Best regards,
Gregor

[soccermax]

Hi @gregorwolf,

Thanks for the feedback.
Can you check if the already available parameter redisOptions is enough for your use case? See documentation: https://cap-js-community.github.io/event-queue/setup/#initialization-parameters

Note: this will only work for non-cluster clients. I need to check again for cluster-clients next week. Implementation for the creation of redis clients is in src/shared/redis

Best,
Max

[gregorwolf]

Hi @soccermax ,

thank you for the quick response. For the moment I've adjusted my instructions: using the redis service from the provider subaccount to add an entry for the BTP redis service hostname in my local hosts file and point to localhost. This allows to run in hybrid mode without any other change.

CU
Gregor