Ensure golangci-lint for the correct OS

[arjunrn]

Attempts to fix #20

Currently the ensure.sh attempts to download the golangci-lint tool even when the tool is present on the path. The ensure.sh will now download the script only when the tool is not present in $PATH. Also other minor improvements:

• Ensure that $GOPATH/bin is present in $PATH.
• Allow user to specify the path for $GOLANGCI_LINT_CACHE

[arjunrn]

/assign @dustman9000 @2uasimojo

[dustman9000]

Ensure that GOOS is defined, default to go env GOOS if not.

[dustman9000]

I tested this by moving golangci-lint out of my $PATH and it's failing locally for me:

$ make
boilerplate/_lib/ensure.sh golangci-lint
# GOLANGCI_LINT_CACHE needs to be set to a directory which is writeable
# Relevant issue - https://github.com/golangci/golangci-lint/issues/734
GOLANGCI_LINT_CACHE=/tmp/golangci-cache golangci-lint run -c boilerplate/openshift/golang_osd_cluster_operator/golangci.yml ./...
bash: /Users/dustinrow/.gvm/pkgsets/go1.13.6/global/bin/golangci-lint: cannot execute binary file
make: *** [gocheck] Error 126
dustinrow@drow-mac:~/src/must-gather-operator$ which golangci-lint
/Users/dustinrow/.gvm/pkgsets/go1.13.6/global/bin/golangci-lint

[arjunrn]

I tested this by moving golangci-lint out of my $PATH and it's failing locally for me:

@dustman9000 You will have to set and pass the GOOS environment variable when calling make. Otherwise it defaults to linux as you suggested.

[dustman9000]

/lgtm

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: arjunrn, dustman9000

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [arjunrn,dustman9000]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[dustman9000]

Tested locally with latest changes and it pulls down the proper golangci-lint regardless of cross-compile GOOS.

[dustman9000]

/label tide/merge-method-squash

[2uasimojo]

This doesn't ensure we're using $GOLANGCI_LINT_VERSION. As written, there are several ways that could go awry even when we're running the gocheck target in a container -- e.g. if the base container image we're using already has the binary (at the wrong version).

So IMO we really ought to include a version check here. Something like:

Suggested change

	if which golangci-lint ; then
	exit
	if which golangci-lint && [[ $(golangci-lint --version) == *" v$GOLANGCI_LINT_VERSION "* ]]; then
	exit

[2uasimojo]

Doesn't the amd64 bit also break on Mac? (ppc or something?)

[arjunrn]

No Macs have used intel x86 architecture for about 10 years now.

[2uasimojo]

TIL.

We're still totally screwing all the people trying to develop on AIX though.