[#548] Specify output formatting when getting cluster_status on RabbitMQ 3.8

[decoyjoe]

Proposed Changes

Fixes #548

Default rabbitmqctl output formatting changed to "table" in RabbitMQ 3.8
Need to explicitly specify "erlang" formatting when getting
cluster_status in order to properly parse output.

Fixes non-idempotency of rabbitmq::cluster recipe on RabbitMQ 3.8.

Types of Changes

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• Bug fix (non-breaking change which fixes issue rabbitmq 3.8 new cluster_status cli output breaks cluster resource #548 )
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (correction or otherwise)
• Cosmetics (whitespace, appearance)

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[michaelklishin]

While it's true that default (meant for interactive use) format of rabbitmq-diagnostics cluster_status has changed in 3.8, it is not "table" but "string". Anyhow, this change is something we can consider.

A better option would be to use --formatter=json and parse JSON, something that's been available since 3.7.0 (and this cookbook doesn't have to worry about 3.6.x since it's been out of support for over two years now). How does this sound?

[decoyjoe]

The current cluster_status parsing logic works fine so I didn't see a need for a refactor to JSON formatting, just a simple change to get it working under RabbitMQ 3.8.

Has this cookbook already dropped support for 3.6.x? If so, I can take a stab at updating the cluster status logic to use --formatter=json instead.

[michaelklishin]

3.6.x has been out of any kind of support for more than two years but yeah, we have never really announced that it's support has been dropped in v5.x. Fair enough, we can continue parsing the Erlang format.

[michaelklishin]

Thank you!

[decoyjoe]

Thanks @michaelklishin. Any idea when this change might be released? This bug is currently affecting us in all environments.

[michaelklishin]

@decoyjoe shouldn't take long but unfortunately, CI is affected by something I cannot explain, and it is fairly distracting. I will likely run all suites locally with Dokken and then cut a release. I suggest that you consume this cookbook via git, from the v5.x branch for now.

[michaelklishin]

5.8.5 is up in Chef Supermarket.

[decoyjoe]

@michaelklishin Fantastic, thanks!