Support parsing of named pipes for compose volumes

[dnephin]

Related to moby/moby#34795

Fixes the client side parsing of volume specs to support windows named pipes.

[codecov-io]

Codecov Report

Merging #560 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #560      +/-   ##
==========================================
+ Coverage    49.5%   49.51%   +<.01%     
==========================================
  Files         208      208              
  Lines       17153    17156       +3     
==========================================
+ Hits         8491     8494       +3     
  Misses       8230     8230              
  Partials      432      432

[StefanScherer]

Thanks for starting this PR.
To have Docker as a tool that gets out of the users way please support (unix) slashes as well. ❤️ 🙏 😃

[StefanScherer]

I wonder if we can make this slash-insensitive (like case-insensitive, but for slashes ;-) ).
From a Mac/Linux client remote controlling a Windows swarm node I guess many people still are used to unix slashes.

I also use eg. docker run -v //./pipe/docker_engine://./pipe/docker_engine -it -p 8080:8080 stefanscherer/visualizer-windows:insider right now and it works pretty good as Golang itself can handle backslashes and slashes in paths.

Slashes because bash needs extra escaped backslashes as you can see here.

´´´
$ docker run -v \.\pipe\docker_engine:\.\pipe\docker_engine -it -p 8080:8080 stefanscherer/visualizer-windows:insider
docker: Error response from daemon: invalid bind mount spec "\.pipedocker_engine:\.pipedocker_engine": invalid volume specification: '.pipedocker_engine:.pipedocker_engine'.

(oops as you can see even GitHub looses some backslashes although I'm using three backticks here)

[dnephin]

Normal slash is already handled in this function on the line above (111). A single / already returns true.

[StefanScherer]

Nice!

[StefanScherer]

It's so convenient to pick the Docker CLI from CircleCI build. So I gave it a try

$ wget https://5607-88013053-gh.circle-artifacts.com/0/work/build/docker-darwin-amd64
$ chmod +x docker-darwin-amd64
$ ./docker-darwin-amd64 service create --name whoami --mount type=bind,source=//./pipe/docker_engine,destination=//./pipe/docker_engine stefanscherer/whoami:insider
vkwsqpgcgm3nso31nw5no8fcx
overall progress: 0 out of 1 tasks 
1/1: invalid mount target, must be an absolute path: //./pipe/docker_engine 

And with backslashes

$ ./docker-darwin-amd64 service create --name whoami --mount 'type=bind,source=\\.\pipe\docker_engine,destination=\\.\pipe\docker_engine' stefanscherer/whoami:insider
cruvatiet5yhuxta2teppqw8b
overall progress: 0 out of 1 tasks 
1/1: invalid mount target, must be an absolute path: \\.\pipe\docker_engine 

running against a Windows Insider with Docker engine 17.09.0-rc2 installed.

Is this another check in cli or in engine?

[dnephin]

Yes, as I mentioned in moby/moby#34795 (comment), this only fixes the client side. docker service create does not do any parsing on the client side. This still needs to be fixed in moby/moby (daemon/cluster/executor/container/validate.go).

[thaJeztah]

LGTM

[vdemeester]

LGTM 🐸