Enable ssh forwarding when building a remote target

[alexcb]

this fixes moby/buildkit#2040 by enabling ssh forwarding when a remote address is given on the command line, this is a similar fix to docker/buildx#581

previously when I ran:

DOCKER_BUILDKIT=1 ./build/docker -D build -t testing git@github.ent.corp:organization/testrepository.git

I could replicate the issue and would get this error:

failed to solve with frontend dockerfile.v0: failed to read dockerfile: failed to load cache key: rpc error: code = Unimplemented desc = unknown service moby.sshforward.v1.SSH

However now with this fix, I get a much more appropriate error showing that my git clone failed:

 => ERROR [internal] load git source git@github.ent.corp:organization/testrepository.git                                                                                                                                                                                0.1s
------                                                                                                                                                                                                                                                                       
 > [internal] load git source git@github.ent.corp:organization/testrepository.git:
#1 0.105 ssh: Could not resolve hostname github.ent.corp: Name or service not known
#1 0.106 fatal: Could not read from remote repository.
#1 0.106 
#1 0.106 Please make sure you have the correct access rights
#1 0.106 and the repository exists.

and when I point it at an actual private repo, it can authenticate and builds as expected.

$ DOCKER_BUILDKIT=1 ./build/docker -D build -t testing 'git@github.com:alexcb/private-repo-with-dockerfile.git#main'
DEBU[0000] serving grpc connection                      
[+] Building 2.6s (5/5) FINISHED                                                                                                                                                                                                                                             
 => [internal] load git source git@github.com:alexcb/private-repo-with-dockerfile.git#main                                                                                                                                                                              1.3s
 => [internal] load metadata for docker.io/library/alpine:latest                                                                                                                                                                                                        0.0s
 => CACHED [1/2] FROM docker.io/library/alpine:latest                                                                                                                                                                                                                   0.0s 
 => [2/2] RUN echo hello private world                                                                                                                                                                                                                                  1.2s 
 => exporting to image                                                                                                                                                                                                                                                  0.0s 
 => => exporting layers                                                                                                                                                                                                                                                 0.0s 
 => => writing image sha256:4fad0d52c1e9a24e4ce4710b589bd94636c52ce8e275461e963ec81a1fe7d8b6                                                                                                                                                                            0.0s 
 => => naming to docker.io/library/testing  

[thaJeztah]

@tonistiigi @crazy-max ptal

[codecov-commenter]

Codecov Report

Merging #3050 (af1bb80) into master (e3dfc24) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #3050      +/-   ##
==========================================
- Coverage   57.99%   57.98%   -0.02%     
==========================================
  Files         302      302              
  Lines       21748    21754       +6     
==========================================
  Hits        12613    12613              
- Misses       8212     8218       +6     
  Partials      923      923              

[tonistiigi]

@alexcb Validation + DCO broken

[alexcb]

It looks like the buildkit dependency version change that @thaJeztah and I made yesterday broke it #3050 (comment)

I suspect we'll need to update the 0.8 branch in the end (to include my PRs up until d3e0a6f2d8c36dcd2d785ab436ead8bd2dc50f28) to make this PR work.

Should I open another PR against https://github.com/moby/buildkit/tree/v0.8 with the required cherry-picks to make this work?

[tonistiigi]

If you need something from master branch that isn't in v0.8 (and isn't a regression bugfix that should be picked anyway) then just vendor from the commit you need.

[alexcb]

If you need something from master branch that isn't in v0.8 (and isn't a regression bugfix that should be picked anyway) then just vendor from the commit you need.

Does this mean I can re-enable my change to vendor.conf, to set it back to what I initially had it set to: github.com/moby/buildkit d3e0a6f2d8c36dcd2d785ab436ead8bd2dc50f28 # needed for util/gitutils?

[tonistiigi]

Yes, @thaJeztah said that the commits you needed should have already been in the release tag. If this is not true then vendor the commit you need.

[alexcb]

thanks for the help @tonistiigi , I rebased this PR off master and the tests are once again passing.

[avroshk]

Would love to get this merged @alexcb!
Please let me know if I can help resolve the conflicts.

[felipematheus]

I'm looking forward for this fix to be merged, would solve a problem with one of my builds.

[thaJeztah]

LGTM