Add warnings client side before deployment on Kubernetes

[silvin-lubecki]

- What I did
I added a bunch of warnings for all the compose features unsupported by the Kubernetes Stack API. They are printed on stderr like this:

> $ docker stack deploy -c docker-compose.yml mystack
top-level network "postgres_conn" is ignored
service postgres: network "postgres_conn" is ignored
service postgres: env_file are ignored
service import-osmborder: network "postgres_conn" is ignored
service import-osmborder: env_file are ignored
service import-osm: network "postgres_conn" is ignored
service import-osm: env_file are ignored
service import-osm-diff: network "postgres_conn" is ignored
service import-osm-diff: env_file are ignored
service update-osm: network "postgres_conn" is ignored
service update-osm: env_file are ignored
service openmaptiles-tools: network "postgres_conn" is ignored
service openmaptiles-tools: env_file are ignored
service import-lakelines: network "postgres_conn" is ignored
service import-lakelines: env_file are ignored
service import-sql: network "postgres_conn" is ignored
service import-sql: env_file are ignored
service generate-changed-vectortiles: network "postgres_conn" is ignored
service generate-changed-vectortiles: env_file are ignored
service postserve: network "postgres_conn" is ignored
service postserve: env_file are ignored
service mapbox-studio: network "postgres_conn" is ignored
service import-wikidata: network "postgres_conn" is ignored
service import-wikidata: env_file are ignored
service generate-vectortiles: network "postgres_conn" is ignored
service generate-vectortiles: env_file are ignored
service import-water: network "postgres_conn" is ignored
service import-water: env_file are ignored
service import-natural-earth: network "postgres_conn" is ignored
service import-natural-earth: env_file are ignored
Waiting for the stack to be stable and running...

⚠️ Depends on #899⚠️

- How I did it
Once the compose file is parsed, I iterate on all services to detect the unsupported features (which are filled) and print a warning on each.

- How to verify it
Find a compose file with some networks and deploy it. Some warnings should be printed on stderr.

- Description for the changelog
Print warnings on stderr for each unsupported features while parsing a compose file for deployment on Kubernetes.

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

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@7ad3036). Click here to learn what that means.
The diff coverage is 36.77%.

@@ Coverage Diff @@## master #903 +/- ##
=========================================
Coverage ? 53.37% =========================================
Files ? 267 Lines ? 16975 Branches ? 0 =========================================
Hits ? 9060 Misses ? 7322 Partials ? 593

[vdemeester]

One nit, otherwise, one question : why doing that on its own instead of doing it while converting the types.Config to the stack struct ?

[vdemeester]

nit: any reason for having stderr as first argument ? 😝

[silvin-lubecki]

For homogenization 😇 ?
https://github.com/docker/cli/blob/master/cli/command/stack/swarm/deploy_bundlefile.go#L100

[vdemeester]

👍

[silvin-lubecki]

There are two reasons why I separated it. First one is for separation of concerns, as it's not a little 5 lines function. Second one is that if you put the warning code in the conversion code, then you may get warnings while you are retrieving some stacks, during a docker stack ls for example. I think we only want warnings on stacks you are deploying.

[dnephin]

Could this use a golden.Assert() for all the warnings, or is it possible for the order to change? Maybe we could sort the output if the order changes?

[silvin-lubecki]

PTAL

[vdemeester]

LGTM on commits that differs from #899

[thaJeztah]

Added [WIP] to the PR title until #899 is merged (reviewing that one)

[thaJeztah]

LGTM, but when rebasing can you quash the last two commits?

[mat007]

Rebase and squashing done.

[thaJeztah]

Thanks! Still LGTM