make compose plugin detection in bash completion work on Mac OS

[varp]

Signed-off-by: Vardan Pogosian vardan.pogosyan@gmail.com

- What I did
Replaced sed invocation with Go templates invocations

- How I did it
Replaced sed invocation with Go templates invocations

- How to verify it
Install docker-compose 2.2.2 as a plugin for docker CLI on Mac OS X and try to auto-complete docker comp<tab>. It will auto-complete to docker compose

- Description for the changelog

Made sed invocation, used at COMPOSER_PLUGIN_PATH detection (for BASH completion) compatible with POSIX 1003.2 RE to properly work on OS X.

- A picture of a cute animal (not mandatory but encouraged)

[varp]

@albers Hello, could you take some action on this?

[albers]

LGTM, thanks.

[albers]

Sorry, there's still one thing to do with your PR: please sign off the commit, see the failing DCO check.

[varp]

@albers done. The commit now has sign

[codecov-commenter]

Codecov Report

Merging #3392 (77b1031) into master (2fe3515) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3392   +/-   ##
=======================================
  Coverage   56.35%   56.35%           
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  Files         304      304           
  Lines       26830    26830           
=======================================
  Hits        15121    15121           
  Misses      10789    10789           
  Partials      920      920           

[albers]

LGTM

[albers]

@thaJeztah PTAL

[thaJeztah]

Thanks @varp

change LGTM, but I left a suggestion; let me know what you (and @albers) think about that approach.

Happy to merge as-is if you don't think it's better (or if you prefer handling that as a follow-up)

[thaJeztah]

I was wondering if we could do it with --format alone, and (while the syntax is a bit awkward), looks like it's possible when combining range and if eq;

docker info --format '{{range .ClientInfo.Plugins}}{{if eq .Name "compose"}}{{.Path}}{{end}}{{end}}'
/usr/local/lib/docker/cli-plugins/docker-compose

The script would then look like;

COMPOSE_PLUGIN_PATH=$(docker info --format '{{range .ClientInfo.Plugins}}{{if eq .Name "compose"}}{{.Path}}{{end}}{{end}}')

[thaJeztah]

There's one small difference; the docker info --format always prints a newline, whereas the sed variant does not; if I replace compose with nosuch (to mimic a situation where the compose plugin is not installed);

docker info --format '{{range .ClientInfo.Plugins}}{{if eq .Name "nosuch"}}{{.Path}}{{end}}{{end}}'
# prints an empty line

docker info --format '{{json .ClientInfo.Plugins}}' | sed -n -E 's/.*"Path":"([^"]+docker-nosuch)".*/\1/p'
# doesn't print an empty line

But I don't think that's a problem as the script checks if $COMPOSE_PLUGIN_PATH contains a valid path, and that still looks to work ok with that;

# for the "nosuch" plugin:

COMPOSE_PLUGIN_PATH=$(docker info --format '{{range .ClientInfo.Plugins}}{{if eq .Name "nosuch"}}{{.Path}}{{end}}{{end}}')
if [ -f "$COMPOSE_PLUGIN_PATH" ] ; then echo YES; fi

# doesn't print anything

# for the "compose" plugin:
COMPOSE_PLUGIN_PATH=$(docker info --format '{{range .ClientInfo.Plugins}}{{if eq .Name "compose"}}{{.Path}}{{end}}{{end}}')
if [ -f "$COMPOSE_PLUGIN_PATH" ] ; then echo YES; fi

# prints "YES"

[albers]

@thaJeztah Your suggestion has the advantage that it accesses the information in a structured way (i.e. by .Name) instead of text based operations that rely on naming conventions.
So I think we should go this way.

[varp]

@albers Should do I bring a new PR and decline this one with the solution suggested by @thaJeztah or just force push a new commit and change the PR description and the name?
I'm asking because the PR already has approves and assigned milestone.
As a compromise, I could bring suggestions by @thaJeztah in a new PR for the next milestone (not the assigned one - 21.xx)

[albers]

I think it's best to force-push and then update the PR title to a more intention revealing wording, something like "make compose plugin detection in bash completion work on Mac OS"

[varp]

@albers It's done

[albers]

LGTM, thanks @varp

[thaJeztah]

LGTM, thank you!!