bookingcom/shipper

lint fixups

vetshadow can be very useful. However, shadowing 'err' is incredibly
common, rarely harmful, and requires writing non-idiomatic Go in order
to avoid. So, let's filter that out.

One minor bug fixed: bash filename autocompletion for shipperctl apply
was not working.

One minor judgement call: if we can't set up /metrics, this is a fatal
error.

Examples:

cmd/shipper-state-metrics/main.go:95:21⚠️ error return value not
checked (srv.ListenAndServe()) (errcheck)

cmd/shipper/main.go:255:20⚠️ error return value not checked
(srv.ListenAndServe()) (errcheck)

cmd/shipperctl/cmd/apply.go:47:27⚠️ error return value not
checked (applyCmd.MarkFlagFilename("config", "yaml")) (errcheck)

cmd/shipperctl/cmd/apply.go:48:27⚠️ error return value not
checked (applyCmd.MarkFlagFilename("kube-config", "yaml")) (errcheck)

cmd/shipperctl/cmd/apply.go:387:16⚠️ error return value not
checked (yaml.Unmarshal(configBytes, configuration)) (errcheck)

The patch in traffic/errors.go is a targeted fix; the larger scale
solution is to implement structured errors throughout Shipper.

(kudos to @ksurent, who implemented this new check in staticcheck)

Examples:

pkg/testing/util.go:182:2⚠️ unreachable case clause:
github.com/bookingcom/shipper/vendor/k8s.io/client-go/testing.CreateAction
will always match before
github.com/bookingcom/shipper/vendor/k8s.io/client-go/testing.UpdateAction
(SA4020) (staticcheck)

pkg/testing/util.go:197:2⚠️ unreachable case clause:
github.com/bookingcom/shipper/vendor/k8s.io/client-go/testing.GetAction
will always match before
github.com/bookingcom/shipper/vendor/k8s.io/client-go/testing.DeleteAction
(SA4020) (staticcheck)

Examples:

cmd/shipper-state-metrics/main.go:119:7⚠️ receiver name should
not be an underscore, omit the name if it is unused (ST1006)
(staticcheck)

cmd/shipper/main.go:234:7⚠️ receiver name should not be an
underscore, omit the name if it is unused (ST1006) (staticcheck)

Examples:

pkg/chart/cache/cache.go:94:20⚠️ error strings should not end
with punctuation or a newline (ST1005) (staticcheck)

pkg/clusterclientstore/queue.go:48:37⚠️ error strings should not
be capitalized (ST1005) (staticcheck)

Example:

pkg/controller/traffic/pod_label_shifter.go:55:15⚠️ should omit
value from range; this loop is equivalent to `for cluster := range ...`
(S1005) (staticcheck)

megacheck was merged into staticcheck

… breaking the pipeline

…oUrl validation

(or lack thereof)

shipperctl's usage of the context name for the Cluster object fails if that context name is not an acceptable Kubernetes object name, as is the case in GKE clusters and their underscores.

This helps people work around the issue in #61, but a better fix will be for shipperctl to give immediate feedback when it detects that issue.

Removing extra bracket

This allows it to work with, for example, GKE clusters with the 'gcp'
auth provider in ~/.kube/config.

Also tweak the quick install docs to mention that you need to be a real
cluster-admin. On GKE you need to create a clusterrolebinding first;
otherwise you see errors that indicate trying to create the new Shipper
clusterroles is privilege escalation.

This commit includes a giant pile of new stuff in vendor: this is
everything all of the cloud providers for their auth plugins.

Previous change to build docker images on tags was early-exiting because
the branch wasn't master.

this can become the tree for contributor docs

And migrate some content from the API reference style rollout doc that
we already had

Forcing PATH like that makes the container feel very odd if you exec
into it. CA certs are nice if you want to download Helm charts over SSL.

* docs: initial commit

* docs: add deployment.rst

* docs: more docs

* docs: more docs

* docs: more docs

* docs: clean docs

* docs: more docs

* docs: Add Dockerfile for documentation builder

* docs/application: explain what happens when an application object is created

* docs: add more information in Application's "Scope of control" section

* docs: add more Release docs

* docs: expand InstallationTarget concept documentation

* docs: re-touch intro

* docs: api reference draft

* docs: add quick install guide

The start/concepts bits were mostly replaced by the API reference docs.

There's more there that isn't covered, mostly pertaining to
architecture, which still needs to find a home.

* ci: build release tagged images

* docs: start fleshing out administrator's guide

This involved moving application developer docs out of 'operations' to
'user'.