Use custom gRPC dialer to override default proxy dialer

[dani-docker]

Signed-off-by: Dani Louca dani.louca@docker.com

- What I did
Followed the same logic as in #2419 to use a custom grpc dialer and prevent the use of default dialer which picks up the proxy env variable when a manager is joining the cluster.
The affected method dial is only used when manager is joining the cluster and part of checkHealth which is also called on join.

- How to test it

• Follow the link to configure 2 nodes (not part of swarm cluster) to use HTTP Proxy https://docs.docker.com/config/daemon/systemd/#httphttps-proxy
• Enable swarm on node 1 , docker swarm init
• Join node 2 as manager

Actual Result:

[centos@esc-1003-1 ~]$ docker swarm join --token SWMTKN-1-2v3cay35o2yavb2bqge6wvyhg6esdn47g82ydi534npgcd4cym-4rmvy3uo2acmbenjvmf8tkx52 10.10.13.91:2377
Error response from daemon: manager stopped: can't initialize raft node: rpc error: code = Unavailable desc = all SubConns are in TransientFailure, latest connection error: connection error: desc = "transport: Error while dialing dial tcp: lookup proxy.example.com on 10.10.0.2:53: no such host"

Expected Result (with this PR):
Node joins successfully

[root@esc-1003-1 ~]# docker swarm join --token SWMTKN-1-2v3cay35o2yavb2bqge6wvyhg6esdn47g82ydi534npgcd4cym-4rmvy3uo2acmbenjvmf8tkx52 10.10.13.91:2377
This node joined a swarm as a manager.

- Description for the changelog
Fix manager node join when HTTP_PROXY, HTTPS_PROXY, or NO_PROXY are used

[dani-docker]

cc: @anshulpundir @dperny

[dperny]

LGTM. Pretty sure the test failure is known so I'm rebuilding.

[thaJeztah]

Should we have an integration test for this that set an invalid domain (HTTPS_PROXY=myproxy.invalid) as a proxy, then tries to join?

[thaJeztah]

Looks like this is related to moby/moby#36951 and moby/moby#35395 (comment)

[trapier]

We still waiting on CI here? Current failure doesn't look related.

[thaJeztah]

Not a maintainer here, but ideally;

• May be good to update the commit message, and include a bit more context about the reason for this change
• Add an integration test (if possible) to verify the behavior Use custom gRPC dialer to override default proxy dialer #2802 (comment)

I prepared backports, but those will have to be updated if this PR is updated before it's merged

I also triggered CI, but it's now failing on

gometalinter: error: unknown linters: gosimple
make: *** [check] Error 1
Exited with code 2

which should be fixed by #2811 after rebasing this PR

[wk8]

Agreed an integration test would be great :)

[anshulpundir]

+1 for #2802 (comment)

[thaJeztah]

ping @dani-docker can you address the review comments?

[GordonTheTurtle]

Please sign your commits following these rules:
https://github.com/moby/moby/blob/master/CONTRIBUTING.md#sign-your-work
The easiest way to do this is to amend the last commit:

$ git clone -b "esc-1003" git@github.com:dani-docker/swarmkit.git somewhere
$ cd somewhere
$ git rebase -i HEAD~842357316928
editor opens
change each 'pick' to 'edit'
save the file and quit
$ git commit --amend -s --no-edit
$ git rebase --continue # and repeat the amend for each commit
$ git push -f

Amending updates the existing PR. You DO NOT need to open a new one.

[dani-docker]

@thaJeztah
I rebased and updated the comment as requested.
As for the test case, this issue completes the fix in #2419 which is also missing a test, I will look into a test shortly

[thaJeztah]

LGTM

Discussing on slack; the tricky bit with writing a test for this, is that Golang won't use a proxy for local IP-addresses, so there's some work needed to write a test for this.

The change has been manually tests, and works, so I'm ok with going ahead for now and do a test as follow-up

[codecov]

Codecov Report

Merging #2802 into master will increase coverage by 0.03%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2802      +/-   ##
==========================================
+ Coverage   62.12%   62.16%   +0.03%     
==========================================
  Files         139      139              
  Lines       22294    22297       +3     
==========================================
+ Hits        13851    13861      +10     
+ Misses       6973     6964       -9     
- Partials     1470     1472       +2