[Receiver/redisreceiver] Support More Redis Metrics

[singku]

Descriptions

• Add support for maxmemory metric [gauge]
• Add support for role metric [updown counter]
  With replica and primary added as an attribute
• Add support for cmdstat metric
  Currently add calls and usec as two new metrics [sum], and cmd as the attribute for both.
• Fixed info call with all parameter because the comments says all of the 'sections' and command stats is not in the default section.

Related Discussions
open-telemetry/opentelemetry-proto#401
#11025

Tests
Manual tests to see that metrics are added.
Also the existing tests has been updated to fit the new metrics

Documentation
In-place documents added. There are also auto generated document for new metrics.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: singku / name: Andrew Tang (2968a80510b8e63c55b03e0280a8b09a97d2fb76)

[singku]

@codeboten @jpkrohling could someone of you approve the workflow to see if this PR pass the checks? Thanks.

[singku]

Ping for an update.

[pirgeo]

I looked at this mainly for the "Enum as Gauge" perspective, as I have not yet spent a lot of time with receivers on the collector. Someone more familiar with the receiver concept might have more insights into this topic.

[singku]

@codeboten @mx-psi can we re-assign this to someone? Both the reviewer and assignee are not available till July or August.

[dmitryax]

Please update the changelog.

Another Q: Are all the new metrics that significant to be enabled by default? If we do that, this is going to be a breaking change. I recommend adding them as optional metrics.

[singku]

@dmitryax I have removed version metric and changed role metric to be an updowncounter. Also added a change log entry.

[dmitryax]

Thanks @singku . I think my last Q is still not answered:

Are all the new metrics that significant to be enabled by default? If we do that, this is going to be a breaking change. I recommend adding them as optional metrics.

[dmitryax]

Also please update the PR description

[singku]

If they are added as optional. How consumers can config their OTel redisreceiver config to enable them? I didn't find an example.

[dmitryax]

They are added as default metrics. It means that user will start receiving them unexpectedly after the upgrade. Optional metrics are marked as enabled: false in metadata.yaml

[singku]

I understand that. I mean is there a way to configure at runtime so as to enable these optional metrics? If not, consumer has to pull the code and modify it then rebuild the binary to do so.

Or we could re-enable them by default in next breaking change PR?

[dmitryax]

No, all the metrics can be enabled or disabled by configuring the receiver, e.g.:

receivers:
  redis: 
    metrics:
      <metric_name>:
        enabled: <true|false>

[singku]

Sounds good! I have made the change.

Note that since maxmeory is by default disabled, for consumer to enable metrics at runtime so recorder is added. This result in recorder count + 6 keyspace metrics count != the generated datapoint counts. Test needs to be adjusted.

[dmitryax]

LGTM. @pirgeo can you please take a another look since you were involved?

[pirgeo]

Thanks for making the changes - LGTM!

[singku]

@dmitryax @pirgeo @bertysentry thanks for all the comments to this CL. @dmitryax feel free to merge it with appropriate message.