Add .go-version and .golangci.yml

Enable golangci-lint and specify the Go version in a .go-version file.

.ci/Jenkinsfile

@@ -32,6 +32,7 @@ pipeline {
       steps {
         deleteDir()
         gitCheckout(basedir: "${BASE_DIR}")
+        setEnvVar("GO_VERSION", readFile("${BASE_DIR}/.go-version").trim())
         stash allowEmpty: true, name: 'source', useDefaultExcludes: false
       }
     }

.github/workflows/golangci-lint.yml

@@ -0,0 +1,33 @@
+name: golangci-lint
+on:
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Read .go-version file
+        id: goversion
+        run: echo "::set-output name=version::$(cat .go-version)"
+
+      - uses: actions/setup-go@v2
+        with:
+          go-version: "${{ steps.goversion.outputs.version }}"
+
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v2
+        with:
+          version: v1.44.2
+          args: --timeout=5m
+
+          # Ignore pre-existing issues.
+          only-new-issues: true
+
+          # Use the Go version specified in .go-version for consistency.
+          skip-go-installation: true

.go-version

@@ -0,0 +1 @@
+1.17.7

.golangci.yml

@@ -0,0 +1,105 @@
+---
+
+run:
+  issues-exit-code: 1
+  modules-download-mode: readonly
+
+linters:
+  disable-all: true
+  enable:
+    - deadcode
+    - errcheck
+    - gosimple
+    - govet
+    - ineffassign
+    - staticcheck
+    - structcheck
+    - stylecheck
+    - typecheck
+    - unused
+    - varcheck
+    - depguard
+    - errorlint
+    - gofumpt
+    - goimports
+    - godox
+    - goheader
+    - ifshort
+    - misspell
+    - prealloc
+    - unconvert
+    - revive
+  fast: false
+
+linters-settings:
+  goimports:
+    local-prefixes: github.com/elastic/go-libaudit
+  gofumpt:
+    extra-rules: true
+  goheader:
+    # Use https://github.com/elastic/go-licenser to automatically add headers.
+    template: |-
+      Licensed to Elasticsearch B.V. under one or more contributor
+      license agreements. See the NOTICE file distributed with
+      this work for additional information regarding copyright
+      ownership. Elasticsearch B.V. licenses this file to you under
+      the Apache License, Version 2.0 (the "License"); you may
+      not use this file except in compliance with the License.
+      You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing,
+      software distributed under the License is distributed on an
+      "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+      KIND, either express or implied.  See the License for the
+      specific language governing permissions and limitations
+      under the License.
+  revive:
+    enable-all-rules: false
+    # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md
+    rules:
+      - name: bare-return
+      - name: call-to-gc
+      - name: confusing-results
+      - name: constant-logical-expr
+      - name: context-as-argument
+      - name: deep-exit
+      - name: defer
+      - name: duplicated-imports
+      - name: early-return
+      - name: empty-block
+      - name: error-strings
+      - name: errorf
+      - name: exported
+        arguments:
+          - checkPrivateReceivers
+      - name: imports-blacklist
+        arguments:
+          - github.com/pkg/errors
+      - name: increment-decrement
+      - name: range
+      - name: range-val-address
+      - name: range-val-in-closure
+      - name: receiver-naming
+      - name: struct-tag
+      - name: time-naming
+      - name: unconditional-recursion
+      - name: unexported-naming
+      - name: unexported-return
+      - name: unnecessary-stmt
+      - name: unreachable-code
+      - name: unused-parameter
+      - name: unused-receiver
+      - name: var-declaration
+      - name: waitgroup-by-value
+  stylecheck:
+    checks:
+      - all
+
+issues:
+  include:
+   # If you're going to write a comment follow the conventions.
+   # https://go.dev/doc/effective_go#commentary.
+   # comment on exported (.+) should be of the form "(.+)..."
+   - EXC0014