provider/docker: Add extra_hosts parameter for containers

[paulbellamy]

Usage, as in:

resource "docker_container" "example" {
  image = "alpine"
  name = "example"
  command = ["cat", "/etc/hosts"]
  extra_hosts = {
    host = "www.example.com"
    ip = "192.168.1.1"
  }
}

It's equivalent to the docker command-line --add-host host:ip flag, but I've opted for the docker API version (called ExtraHosts), as I feel it works better syntactically.

[jen20]

If this is a set, it's valid to have multiple instances of it. Might this be better named extra_host (singular) or even host such that the set semantics read better?

[paulbellamy]

I'd be more in favour of hosts, so that it matches ports and volumes.

[jen20]

👍 for consistency.

[jen20]

Hi @paulbellamy! Thanks for submitting this. I've left a few comments in line, could you let me know your thoughts on them?

[jen20]

Hi @paulbellamy! I've replied to your comments inline. I merged quite a bit into the docker container resource today, so if you could rebase your work onto master that would be great.

[paulbellamy]

Cool, applied changes and rebased. I also inlined ports and volumes schemas, for consistency.

[jen20]

Thanks @paulbellamy! I pulled this locally and added some acceptance tests. The only other change I made was to rename hosts to host in the schema - which reads more naturally when you define more than one of them. I'll go back shortly and look at whether everything else in the docker provider matches that pattern also. Thanks for the contribution - sorry it took so long to merge!

[ghost]

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