Switch to golangci-lint

[cyriltovena]

I've made the switch to run golang-ci instead of gometalinter.

I've added all supported and not included by default linters of gometalinters and added:

• goimports
• misspell

Excluded files are now automatically handled, but examples/ was also skipped so I'm running the linter twice. See documentation examples below:

 # which dirs to skip: they won't be analyzed;
  # can use regexp here: generated.*, regexp is applied on full path;
  # default value is empty list, but next dirs are always skipped independently
  # from this option's value:
  #   	vendor$, third_party$, testdata$, examples$, Godeps$, builtin$
  skip-dirs:
    - src/external_libs
    - autogenerated_by_my_lib

  # which files to skip: they will be analyzed, but issues from them
  # won't be reported. Default value is empty list, but there is
  # no need to include all autogenerated files, we confidently recognize
  # autogenerated files. If it's not please let us know.
  skip-files:
    - ".*\\.my\\.go$"
    - lib/bad.go

Found some interesting issues (typo and goimports) but also some false positives (dupl).

We should have this tools included in our IDE (there is vs-code support).

Closes #187
Closes #237

[agones-bot]

Build Succeeded 👏

Build Id: 9d7ee559-d2f4-4f95-ad9c-a20a3ef15ebc

The following development artifacts have been built, and will exist for the next 30 days:

• image: gcr.io/agones-images/agones-controller:0.5.0-65cda51
• image: gcr.io/agones-images/agones-sdk:0.5.0-65cda51
• Linux C++ SDK (build: dev): agonessdk-0.5.0-65cda51-dev-linux-arch_64.tar.gz
• Linux C++ SDK (build: runtime): agonessdk-0.5.0-65cda51-runtime-linux-arch_64.tar.gz
• Linux C++ SDK (source): agonessdk-0.5.0-65cda51-src.zip
• SDK Server: agonessdk-server-0.5.0-65cda51.zip

(experimental) To install this version:

• git fetch https://github.com/GoogleCloudPlatform/agones.git pull/346/head:pr_346 && git checkout pr_346
• helm install install/helm/agones --namespace agones-system --name agones --set agones.image.tag=0.5.0-65cda51

[markmandel]

A couple of minor its, and a question.

But overall, this looks like this does a better job than gometalinter for linting, and locks it to a version AND runs faster. 👍 🏅

[agones-bot]

Build Succeeded 👏

Build Id: cf70a62d-23ed-4a57-aac2-c64ffad3b6a8

The following development artifacts have been built, and will exist for the next 30 days:

• image: gcr.io/agones-images/agones-controller:0.5.0-db904c3
• image: gcr.io/agones-images/agones-sdk:0.5.0-db904c3
• Linux C++ SDK (build: dev): agonessdk-0.5.0-db904c3-dev-linux-arch_64.tar.gz
• Linux C++ SDK (build: runtime): agonessdk-0.5.0-db904c3-runtime-linux-arch_64.tar.gz
• Linux C++ SDK (source): agonessdk-0.5.0-db904c3-src.zip
• SDK Server: agonessdk-server-0.5.0-db904c3.zip

(experimental) To install this version:

• git fetch https://github.com/GoogleCloudPlatform/agones.git pull/346/head:pr_346 && git checkout pr_346
• helm install install/helm/agones --namespace agones-system --name agones --set agones.image.tag=0.5.0-db904c3