Allow passing array to env-file parameter

[michaloo]

Hey, thanks for the crane. It works fine and it's very helpful.

Yet I have found one case when I cannot use all Docker features.
In Docker reference there is an information about run command flags related to the environmental variables:

All three flags, -e, --env and --env-file can be repeated

While env parameter in crane is an array type, the env-file is string only, so I can't pass multiple env-files in a container definition.

I have only basic golang knowledge, but it looks that /crane/container.go file needs small changes around RunParameters.RawEnvFile variable to make it working on array of strings.

Thanks again for all the work :)

[michaelsauter]

Thanks, glad you enjoy Crane.
--env-file might have changed, I think it was just a string when I implemented it.

Now, even if your Golang knowledge is quite basic, it's really easy to get into and a pull request would be highly welcome! Should be similar to https://github.com/michaelsauter/crane/blob/c13cb961be4aeeca74c0b182481370af723093bb/crane/container.go#L137-143.

Want to give it a shot?

[bjaglin]

To be backward-compatible, and for sanity, I am wondering if it should also be possible to provide a string-value env-file as the syntax allows it today (and not be forced to use a single-element array) a la https://github.com/michaelsauter/crane/blob/c13cb96/crane/container.go#L232-L243. That would need to be done consistently for all flags that can be repeated though, so I guess it could be done in a separate PR.

[michaelsauter]

Crane is still not past 1.0, so I'm OK with breaking behaviour. I always wanted to be as close to raw Docker commands/flags as possible, so I think this is best implemented as array-only as that is what the official docs suggest.

[michaelsauter]

Closed via #98.