PMM-7806: add compatibility with percona pg exporter

.github/workflows/go.yml

@@ -0,0 +1,75 @@
+name: Go
+
+on: 
+  push:
+    branches:
+      - main
+    tags:
+      - v[0-9]+.[0-9]+.[0-9]+*
+  pull_request:
+
+jobs:
+  test:
+    name: Test
+    strategy:
+      matrix:
+        go-version:
+          - 1.17
+        postgresql-image:
+          - postgres:10
+          - postgres:11
+          - postgres:12
+        include:
+          - go-version: tip
+            os: ubuntu-latest
+            postgresql-image: postgres:12
+            may-fail: true
+    runs-on: ubuntu-latest
+    # The environment this job references
+    environment:
+      name: CI
+    steps:
+    - name: Set up Go release
+      if: matrix.go-version != 'tip'
+      uses: percona-platform/setup-go@v2
+      with:
+        go-version: ${{ matrix.go-version }}
+    - name: Set up Go tip
+      if: matrix.go-version == 'tip'
+      env:
+        # to avoid error due to `go version` accepting -v flag with an argument since 1.15
+        GOFLAGS: ""
+      run: |
+        git clone --depth=1 https://go.googlesource.com/go $HOME/gotip
+        cd $HOME/gotip/src
+        ./make.bash
+        echo "GOROOT=$HOME/gotip" >> $GITHUB_ENV
+        echo "$HOME/gotip/bin" >> $GITHUB_PATH
+    - name: Checkout code
+      uses: percona-platform/checkout@v2
+    - name: Run checks
+      run: |
+        go build -modfile=tools/go.mod -o bin/golangci-lint github.com/golangci/golangci-lint/cmd/golangci-lint
+        go build -modfile=tools/go.mod -o bin/reviewdog github.com/reviewdog/reviewdog/cmd/reviewdog
+        bin/golangci-lint run -c=.golangci-required.yml --out-format=line-number | env REVIEWDOG_GITHUB_API_TOKEN=${{ secrets.GITHUB_TOKEN }} bin/reviewdog -f=golangci-lint -level=error -reporter=github-pr-check
+        bin/golangci-lint run -c=.golangci.yml --out-format=line-number | env REVIEWDOG_GITHUB_API_TOKEN=${{ secrets.GITHUB_TOKEN }} bin/reviewdog -f=golangci-lint -level=error -reporter=github-pr-review
+    - name: Run Tests
+      run: |
+        sudo chown 999:999 testdata/ssl/server/*
+        sudo chmod 600 testdata/ssl/server/*
+        docker-compose up -d
+        make
+        make test
+      env:
+        POSTGRESQL_IMAGE: ${{ matrix.postgresql-image }}
+    - name: Run debug commands on failure
+      if: ${{ failure() }}
+      run: |
+        env
+        go version
+        go env
+        pwd
+        git status
+        docker --version
+        docker-compose --version
+        docker-compose logs

cmd/postgres_exporter/main.go

@@ -37,7 +37,6 @@ var (
 	disableDefaultMetrics  = kingpin.Flag("disable-default-metrics", "Do not include default metrics.").Default("false").Envar("PG_EXPORTER_DISABLE_DEFAULT_METRICS").Bool()
 	disableSettingsMetrics = kingpin.Flag("disable-settings-metrics", "Do not include pg_settings metrics.").Default("false").Envar("PG_EXPORTER_DISABLE_SETTINGS_METRICS").Bool()
 	autoDiscoverDatabases  = kingpin.Flag("auto-discover-databases", "Whether to discover the databases on a server dynamically.").Default("false").Envar("PG_EXPORTER_AUTO_DISCOVER_DATABASES").Bool()
-	queriesPath            = kingpin.Flag("extend.query-path", "Path to custom queries to run.").Default("").Envar("PG_EXPORTER_EXTEND_QUERY_PATH").String()
 	onlyDumpMaps           = kingpin.Flag("dumpmaps", "Do not run, simply dump the maps.").Bool()
 	constantLabelsList     = kingpin.Flag("constantLabels", "A list of label=value separated by comma(,).").Default("").Envar("PG_EXPORTER_CONSTANT_LABELS").String()
 	excludeDatabases       = kingpin.Flag("exclude-databases", "A list of databases to remove when autoDiscoverDatabases is enabled").Default("").Envar("PG_EXPORTER_EXCLUDE_DATABASES").String()
@@ -100,7 +99,6 @@ func main() {
 		DisableDefaultMetrics(*disableDefaultMetrics),
 		DisableSettingsMetrics(*disableSettingsMetrics),
 		AutoDiscoverDatabases(*autoDiscoverDatabases),
-		WithUserQueriesPath(*queriesPath),
 		WithConstantLabels(*constantLabelsList),
 		ExcludeDatabases(*excludeDatabases),
 		IncludeDatabases(*includeDatabases),
@@ -115,6 +113,9 @@ func main() {
 
 	prometheus.MustRegister(exporter)
 
+	cleanup := initializePerconaExporters(dsn, opts)
+	defer cleanup()
+
 	pe, err := collector.NewPostgresCollector(
 		logger,
 		dsn,