Integrate golangci-lint linter

Integrate golangci-lint, which is a full-featured linter tool that
includes the checks from 'go vet' and many more.  Borrowed the
install_linter script from airship/airshipctl to install the script
from upstream. Address issues uncovered by the tool.

Change-Id: If30e0819f5d03243e4004bca07951f8aa5218749

.gitignore

@@ -1,2 +1,3 @@
 # Coverage File
 coverage.out
+tools/bin

.golangci.yaml

@@ -0,0 +1,152 @@
+# This file contains all available configuration options
+# with their default values.
+
+# options for analysis running
+run:
+  # default concurrency is a available CPU number
+  concurrency: 4
+
+  # timeout for analysis, e.g. 30s, 5m, default is 1m
+  deadline: 5m
+
+  # exit code when at least one issue was found, default is 1
+  issues-exit-code: 1
+
+  # include test files or not, default is true
+  tests: true
+
+  # list of build tags, all linters use it. Default is empty list.
+  # build-tags:
+  #   - mytag
+
+  # 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
+
+  # by default isn't set. If set we pass it to "go list -mod={option}". From "go help modules":
+  # If invoked with -mod=readonly, the go command is disallowed from the implicit
+  # automatic updating of go.mod described above. Instead, it fails when any changes
+  # to go.mod are needed. This setting is most useful to check that go.mod does
+  # not need updates, such as in a continuous integration and testing system.
+  # If invoked with -mod=vendor, the go command assumes that the vendor
+  # directory holds the correct copies of dependencies and ignores
+  # the dependency descriptions in go.mod.
+  # modules-download-mode: readonly|release|vendor
+
+
+# output configuration options
+output:
+  # colored-line-number|line-number|json|tab|checkstyle|code-climate, default is "colored-line-number"
+  format: colored-line-number
+
+  # print lines of code with issue, default is true
+  print-issued-lines: true
+
+  # print linter name in the end of issue text, default is true
+  print-linter-name: true
+
+
+# all available settings of specific linters
+linters-settings:
+  errcheck:
+    # report about not checking of errors in type assetions: `a := b.(MyStruct)`;
+    # default is false: such cases aren't reported by default.
+    check-type-assertions: false
+
+    # report about assignment of errors to blank identifier: `num, _ := strconv.Atoi(numStr)`;
+    # default is false: such cases aren't reported by default.
+    check-blank: false
+
+    # path to a file containing a list of functions to exclude from checking
+    # see https://github.com/kisielk/errcheck#excluding-functions for details
+    # exclude: /path/to/file.txt
+  govet:
+    # report about shadowed variables
+    check-shadowing: true
+  gofmt:
+    # simplify code: gofmt with `-s` option, true by default
+    simplify: true
+  goimports:
+    # put imports beginning with prefix after 3rd-party packages;
+    # it's a comma-separated list of prefixes
+    local-prefixes: opendev.org/airship/airshipui
+  gocyclo:
+    # minimal code complexity to report, 30 by default (but we recommend 10-20)
+    min-complexity: 15
+  dupl:
+    # tokens count to trigger issue, 150 by default
+    threshold: 100
+  goconst:
+    # minimal length of string constant, 3 by default
+    min-len: 3
+    # minimal occurrences count to trigger, 3 by default
+    min-occurrences: 3
+  misspell:
+    # Correct spellings using locale preferences for US or UK.
+    # Default is to use a neutral variety of English.
+    # Setting locale to US will correct the British spelling of 'colour' to 'color'.
+    locale: US
+    # ignore-words:
+    #   - someword
+  lll:
+    # max line length, lines longer will be reported. Default is 120.
+    # '\t' is counted as 1 character by default, and can be changed with the tab-width option
+    line-length: 120
+    # tab width in spaces. Default to 1.
+    tab-width: 1
+  unused:
+    # treat code as a program (not a library) and report unused exported identifiers; default is false.
+    # XXX: if you enable this setting, unused will report a lot of false-positives in text editors:
+    # if it's called for subdir of a project it can't find funcs usages. All text editor integrations
+    # with golangci-lint call it on a directory with the changed file.
+    check-exported: false
+  unparam:
+    # Inspect exported functions, default is false. Set to true if no external program/library imports your code.
+    # XXX: if you enable this setting, unparam will report a lot of false-positives in text editors:
+    # if it's called for subdir of a project it can't find external interfaces. All text editor integrations
+    # with golangci-lint call it on a directory with the changed file.
+    check-exported: false
+  nakedret:
+    # make an issue if func has more lines of code than this setting and it has naked returns; default is 30
+    max-func-lines: 10
+  prealloc:
+    # XXX: we don't recommend using this linter before doing performance profiling.
+    # For most programs usage of prealloc will be a premature optimization.
+
+    # Report preallocation suggestions only on simple loops that have no returns/breaks/continues/gotos in them.
+    # True by default.
+    simple: true
+    range-loops: true # Report preallocation suggestions on range loops, true by default
+    for-loops: false # Report preallocation suggestions on for loops, false by default
+
+linters:
+  disable-all: true
+  enable:
+    - dupl                 # Tool for code clone detection
+    - goconst              # Finds repeated strings that could be replaced by a constant
+    - gocritic             # The most opinionated Go source code linter
+    - gocyclo              # Computes and checks the cyclomatic complexity of functions
+    - gofmt                # Gofmt checks whether code was gofmt-ed. By default this tool runs with -s option to check for code simplification
+    - goimports            # Goimports does everything that gofmt does. Additionally it checks unused imports
+    - gosec                # Inspects source code for security problems
+    - interfacer           # Linter that suggests narrower interface types
+    - lll                  # Reports long lines
+    - misspell             # Finds commonly misspelled English words in comments
+    - nakedret             # Finds naked returns in functions greater than a specified function length
+    - prealloc             # Finds slice declarations that could potentially be preallocated
+    - scopelint            # Scopelint checks for unpinned variables in go programs
+    - unconvert            # Remove unnecessary type conversions
+    - unparam              # Reports unused function parameters

Makefile

@@ -5,6 +5,12 @@ SHELL=/bin/bash
 # Obtain the version and git commit info
 GIT_VERSION=$(shell git describe --match 'v*' --always)
 
+TOOLBINDIR    := tools/bin
+LINTER        := $(TOOLBINDIR)/golangci-lint
+LINTER_CONFIG := .golangci.yaml
+
+TESTFLAGS     ?=
+
 # Override the value of the version variable in main.go
 LD_FLAGS= '-X main.version=$(GIT_VERSION)'
 GO_FLAGS= -ldflags=$(LD_FLAGS)
@@ -29,27 +35,28 @@ $(PLUGINS):
 	go build -o $(OCTANT_PLUGINSTUB_DIR)/$@-plugin $(GO_FLAGS) opendev.org/airship/airshipui/cmd/$@
 
 .PHONY: test
-test: generate
-	go test $(RECURSIVE_DIRS) -v -coverprofile=coverage.out
+test:
+	go test $(RECURSIVE_DIRS) -v $(TESTFLAGS)
 
-.PHONY: coverage-html
-coverage-html: test
+.PHONY: cover
+cover: TESTFLAGS += -coverprofile=coverage.out
+cover: test
 	go tool cover -html=coverage.out
 
-.PHONY: vet
-vet:
-	go vet $(RECURSIVE_DIRS)
-
-.PHONY: generate
-generate:
-	go generate -v $(RECURSIVE_DIRS)
-
 .PHONY: clean
 clean:
 	git clean -dx $(DIRS)
 
 .PHONY: ci
-ci: test vet
+ci: test lint
 
 # The golang-unit zuul job calls the env target, so create one
 .PHONY: env
+
+.PHONY: lint
+lint: $(LINTER)
+	$(LINTER) run --config $(LINTER_CONFIG)
+
+$(LINTER):
+	mkdir -p $(TOOLBINDIR)
+	./tools/install_linter

cmd/airshipui/main.go

@@ -4,12 +4,12 @@ import (
 	"fmt"
 	"log"
 
-	"opendev.org/airship/airshipui/internal/plugin/airshipui"
+	plugin "opendev.org/airship/airshipui/internal/plugin/airshipui"
 )
 
 var (
 	pluginName = "airship-ui"
-	// version will be overriden by ldflags supplied in Makefile
+	// version will be overridden by ldflags supplied in Makefile
 	version = "(dev-version)"
 )
 

internal/plugin/airshipui/register_test.go

@@ -14,7 +14,10 @@ func TestRegister(t *testing.T) {
 		t.Fatalf("Registering the plugin returned an error")
 	}
 
-	p.Validate()
+	err = p.Validate()
+	if err != nil {
+		t.Fatalf("Validating the plugin returned an error")
+	}
 }
 
 func TestRoutes(t *testing.T) {
@@ -37,6 +40,7 @@ func TestRoutes(t *testing.T) {
 	}
 
 	for _, test := range tests {
+		test := test // pin the value so that the following function literal binds to it
 		t.Run(fmt.Sprintf("Path='%s'", test.path), func(t *testing.T) {
 			_, found := router.Match(test.path)
 
@@ -66,6 +70,7 @@ func TestRouteHandles(t *testing.T) {
 	}
 
 	for _, test := range tests {
+		test := test // pin the value so that the following function literal binds to it
 		t.Run(fmt.Sprintf("Path='%s'", test.path), func(t *testing.T) {
 			handleFunc, found := router.Match(test.path)
 

tools/install_linter

@@ -0,0 +1,11 @@
+#!/bin/bash
+set -x
+
+tools_bin_dir="${BASH_SOURCE%/*}"
+download_url=https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh
+version=v1.21.0
+
+if ! curl -sfL "$download_url" | sh -s -- -b "$tools_bin_dir/bin" "$version"; then
+  printf "Something went wrong while installing golangci-lint\n" 1>&2
+  exit 1
+fi