Show logs for a specific plugin

[zubron]

What this PR does / why we need it:
Add a new flag to the logs command to show the logs only for a
specific plugin. If not provided, or no pods are found for the plugin,
default to showing all logs.

We didn't have a way to uniquely identify pods for a plugin, so this
change adds a new label when creating Pods and DaemonSets which can
be used to filter the pods. This means that the flag will not work
for older versions of Sonobuoy, but it will still default to showing
all logs which was the original behaviour.

Signed-off-by: Bridget McErlean [email protected]

Which issue(s) this PR fixes

• Fixes Sonobuoy logs should allow specification of a single plugin #702

Release note:

Sonobuoy can now show only the logs for a specific plugin by using the flag `--plugin <plugin_name>` when using the logs command.

[codecov-io]

Codecov Report

Merging #868 into master will increase coverage by 0.27%.
The diff coverage is 88.46%.

@@            Coverage Diff             @@
##           master     #868      +/-   ##
==========================================
+ Coverage    46.9%   47.18%   +0.27%     
==========================================
  Files          75       75              
  Lines        4863     4881      +18     
==========================================
+ Hits         2281     2303      +22     
+ Misses       2450     2448       -2     
+ Partials      132      130       -2

Impacted Files	Coverage Δ
pkg/client/interfaces.go	82.5% <ø> (ø)	⬆️
pkg/plugin/driver/job/job.go	75.2% <100%> (+0.2%)	⬆️
pkg/plugin/driver/daemonset/daemonset.go	66.87% <100%> (+0.21%)	⬆️
cmd/sonobuoy/app/logs.go	38.88% <50%> (+0.65%)	⬆️
pkg/client/logs.go	40.16% <87.5%> (+7.75%)	⬆️
pkg/plugin/aggregation/aggregator.go	83.2% <0%> (+4%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update bc64713...54094f1. Read the comment docs.

[johnSchnake]

Seems like that sonobuoy-plugin label got removed accidentally when we moved away from template files. https://github.com/heptio/sonobuoy/pull/834/files#diff-90fec45294302b8f99ef89e826ce7e9bL30

LGTM but I'm going to run it manually to double check and then I'll approve.

[johnSchnake]

Worked as expected for sonobuoy logs and sonobuoy logs --follow 👍

[zubron]

Seems like that sonobuoy-plugin label got removed accidentally when we moved away from template files. https://github.com/heptio/sonobuoy/pull/834/files#diff-90fec45294302b8f99ef89e826ce7e9bL30

The sonobuoy-plugin line shown in that commit was for an annotation. We still have those annotations (https://github.com/heptio/sonobuoy/blob/master/pkg/plugin/driver/daemonset/daemonset.go#L88) but the docs for annotations say that they shouldn't be used for identifying objects so that's why we have to now include the label as well. Still means that this new client won't work with the older versions :(