Add linter

.github/workflows/pr-build.yaml

@@ -19,7 +19,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@d0a58c1c4d2b25278816e339b944508c875f3613 #v3.4.0
         with:
-          go-version: 1.18.x
+          go-version: 1.19.x
       - name: Restore Go cache
         uses: actions/cache@9b0c1fce7a93df8e3bb8926b0d6e9d89e92f20a7 #v3.0.11
         with:
@@ -32,18 +32,26 @@ jobs:
         with:
           version: v0.11.1
           image: kindest/node:v1.21.1@sha256:69860bda5563ac81e3c0057d654b5253219618a22ec3a346306239bba8cfa1a6
-      - name: Setup Kustomize
-        uses: fluxcd/pkg/actions/kustomize@main
-      - name: Setup envtest
-        uses: fluxcd/pkg/actions/envtest@main
-        with:
-          version: "1.21.2"
-      - name: Setup Helm
-        uses: fluxcd/pkg/actions/helm@main
+      - name: Setup kustomize
+        shell: bash
+        run: |
+          curl --silent --location --remote-name "https://github.com/kubernetes-sigs/kustomize/releases/download/kustomize%2Fv4.5.7/kustomize_v4.5.7_linux_amd64.tar.gz"
+          tar xvzf kustomize_v4.5.7_linux_amd64.tar.gz 
+          sudo mv kustomize /usr/local/bin/kustomize
+          rm -rfv *.tar.gz
+          kustomize version
+      - name: Install Helm
+        uses: azure/setup-helm@f382f75448129b3be48f8121b9857be18d815a82 #v3.4
+      - name: fmt
+        run: make fmt
+      - name: vet
+        run: make vet
+      - name: lint
+        run: make lint
       - name: Run tests
         run: make test
       - name: Send go coverage report
-        uses: shogo82148/actions-goveralls@v1
+        uses: shogo82148/actions-goveralls@31ee804b8576ae49f6dc3caa22591bc5080e7920 #v1.6.0
         with:
           path-to-profile: coverage.out
       - name: Check if working tree is dirty

.github/workflows/release.yaml

@@ -18,9 +18,9 @@ jobs:
         uses: actions/checkout@755da8c3cf115ac066823e79a1e1788f8940201b #v3
       - uses: actions/setup-go@d0a58c1c4d2b25278816e339b944508c875f3613 #v3.4.0
         with:
-          go-version: '1.18'
+          go-version: '1.19'
       - name: Docker Login
-        uses: docker/login-action@v2
+        uses: docker/login-action@f4ef78c080cd8ba55a85445d5b36e214a81df20a #v2.1.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
@@ -35,5 +35,4 @@ jobs:
           version: latest
           args: release --rm-dist --skip-validate
         env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          REPO_TOKEN: ${{ secrets.REPO_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Makefile

@@ -22,8 +22,14 @@ integrations    := $(shell $(GO) list ./... | grep cmd)
 PREFIX              ?= $(shell pwd)
 BIN_DIR             ?= $(shell pwd)
 
+# Get the currently used golang install path (in GOPATH/bin, unless GOBIN is set)
+ifeq (,$(shell go env GOBIN))
+GOBIN=$(shell go env GOPATH)/bin
+else
+GOBIN=$(shell go env GOBIN)
+endif
 
-all: deps vet fmt test build
+all: deps vet fmt lint test build
 
 style:
 	@echo ">> checking code style"
@@ -39,6 +45,15 @@ integrationtest:
 	@echo ">> running integration tests"
 	@$(GO) test -short -race -v  $(integrations)
 
+GOLANGCI_LINT = $(GOBIN)/golangci-lint
+.PHONY: golangci-lint
+golangci-lint: ## Download golint locally if necessary
+	$(call go-install-tool,$(GOLANGCI_LINT),github.com/golangci/golangci-lint/cmd/[email protected])
+
+.PHONY: lint
+lint: golangci-lint ## Run golangci-lint against code
+	$(GOLANGCI_LINT) run ./...
+
 deps:
 	@echo ">> install dependencies"
 	@$(GO) mod download
@@ -86,3 +101,16 @@ undeploy-test: ## Undeploy exporter from the K8s cluster specified in ~/.kube/co
 	$(KUSTOMIZE) build config/test | kubectl delete --ignore-not-found=$(ignore-not-found) -f -
 
 .PHONY: all style fmt build test vet
+
+# go-install-tool will 'go install' any package $2 and install it to $1
+define go-install-tool
+@[ -f $(1) ] || { \
+set -e ;\
+TMP_DIR=$$(mktemp -d) ;\
+cd $$TMP_DIR ;\
+go mod init tmp ;\
+echo "Downloading $(2)" ;\
+env -i bash -c "GOBIN=$(GOBIN) PATH=$(PATH) GOPATH=$(shell go env GOPATH) GOCACHE=$(shell go env GOCACHE) go install $(2)" ;\
+rm -rf $$TMP_DIR ;\
+}
+endef

cmd/integration_test.go

@@ -78,7 +78,10 @@ func executeIntegrationTest(t *testing.T, test integrationTest) {
 	container, err := setupMongoDBContainer(context.TODO(), test.mongodbImage)
 	assert.NoError(t, err)
 	opts := options.Client().ApplyURI(container.URI)
-	defer container.Terminate(context.TODO())
+
+	defer func() {
+		assert.NoError(t, container.Terminate(context.TODO()))
+	}()
 
 	client, err := mongo.Connect(context.TODO(), opts)
 	assert.NoError(t, err)
@@ -92,7 +95,10 @@ func executeIntegrationTest(t *testing.T, test integrationTest) {
 	b := bytes.NewBufferString("")
 	rootCmd.SetOut(b)
 	rootCmd.SetArgs(args)
-	go rootCmd.Execute()
+
+	go func() {
+		assert.NoError(t, rootCmd.Execute())
+	}()
 
 	//binding is blocking, do this async but wait 200ms for tcp port to be open
 	time.Sleep(200 * time.Millisecond)
@@ -118,7 +124,7 @@ func executeIntegrationTest(t *testing.T, test integrationTest) {
 	assert.Len(t, test.expectedMetrics, found)
 
 	//tear down http server and unregister collector
-	srv.Shutdown(context.TODO())
+	assert.NoError(t, srv.Shutdown(context.TODO()))
 	prometheus.Unregister(promCollector)
 }
 
@@ -156,40 +162,84 @@ func setupMongoDBContainer(ctx context.Context, image string) (*mongodbContainer
 	return &mongodbContainer{Container: container, URI: uri}, nil
 }
 
+type testRecord struct {
+	document   bson.M
+	database   string
+	collection string
+}
+
 func setupTestData(t *testing.T, client *mongo.Client) {
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
-	_, err := client.Database("mydb").Collection("objects").InsertOne(ctx, bson.M{
-		"foo": "bar",
-	})
-	assert.NoError(t, err)
+	testData := []testRecord{
+		{
+			database:   "mydb",
+			collection: "objects",
+			document: bson.M{
+				"foo": "bar",
+			},
+		},
+		{
+			database:   "mydb",
+			collection: "objects",
+			document: bson.M{
+				"foo": "foo",
+			},
+		},
+		{
+			database:   "mydb",
+			collection: "queue",
+			document: bson.M{
+				"class":  "foobar",
+				"status": 1,
+			},
+		},
+		{
+			database:   "mydb",
+			collection: "queue",
+			document: bson.M{
+				"class":  "foobar",
+				"status": 1,
+			},
+		},
+		{
+			database:   "mydb",
+			collection: "queue",
+			document: bson.M{
+				"class":  "bar",
+				"status": 2,
+			},
+		},
+		{
+			database:   "mydb",
+			collection: "events",
+			document: bson.M{
+				"type":    "bar",
+				"created": time.Now(),
+			},
+		},
+		{
+			database:   "mydb",
+			collection: "events",
+			document: bson.M{
+				"type":    "bar",
+				"created": time.Now(),
+			},
+		},
+		{
+			database:   "mydb",
+			collection: "events",
+			document: bson.M{
+				"type":    "foo",
+				"created": time.Now(),
+			},
+		},
+	}
+
+	for _, record := range testData {
+		_, err := client.Database(record.database).Collection(record.collection).InsertOne(ctx, record.document)
+		assert.NoError(t, err)
+	}
 
-	client.Database("mydb").Collection("objects").InsertOne(ctx, bson.M{
-		"foo": "foo",
-	})
-	client.Database("mydb").Collection("queue").InsertOne(ctx, bson.M{
-		"class":  "foobar",
-		"status": 1,
-	})
-	client.Database("mydb").Collection("queue").InsertOne(ctx, bson.M{
-		"class":  "foobar",
-		"status": 1,
-	})
-	client.Database("mydb").Collection("queue").InsertOne(ctx, bson.M{
-		"class":  "bar",
-		"status": 2,
-	})
-	client.Database("mydb").Collection("events").InsertOne(ctx, bson.M{
-		"type":    "bar",
-		"created": time.Now(),
-	})
-	client.Database("mydb").Collection("events").InsertOne(ctx, bson.M{
-		"type":    "bar",
-		"created": time.Now(),
-	})
-	client.Database("mydb").Collection("events").InsertOne(ctx, bson.M{
-		"type":    "foo",
-		"created": time.Now(),
-	})
 }

cmd/root.go

@@ -44,7 +44,7 @@ var (
 			//reg := prometheus.NewRegistry()
 			prometheus.MustRegister(c)
 			promCollector = c
-			c.StartCacheInvalidator()
+			_ = c.StartCacheInvalidator()
 			srv = buildHTTPServer(prometheus.DefaultGatherer, conf)
 			err = srv.ListenAndServe()
 
@@ -114,7 +114,7 @@ func buildHTTPServer(reg prometheus.Gatherer, conf config.Config) *http.Server {
 }
 
 func main() {
-	rootCmd.Execute()
+	_ = rootCmd.Execute()
 }
 
 func init() {
@@ -126,18 +126,18 @@ func init() {
 	rootCmd.PersistentFlags().StringVarP(&bind, "bind", "b", config.DefaultBindAddr, "Address to bind http server (default is :9412)")
 	rootCmd.PersistentFlags().StringVarP(&metricsPath, "path", "p", config.DefaultMetricsPath, "Metric path (default is /metrics)")
 	rootCmd.PersistentFlags().DurationVarP(&queryTimeout, "query-timeout", "t", config.DefaultQueryTimeout, "Timeout for MongoDB queries")
-	viper.BindPFlag("log.level", rootCmd.PersistentFlags().Lookup("log-level"))
-	viper.BindPFlag("log.encoding", rootCmd.PersistentFlags().Lookup("log-encoding"))
-	viper.BindPFlag("bind", rootCmd.PersistentFlags().Lookup("bind"))
-	viper.BindPFlag("metricsPath", rootCmd.PersistentFlags().Lookup("path"))
-	viper.BindPFlag("mongodb.uri", rootCmd.PersistentFlags().Lookup("uri"))
-	viper.BindPFlag("mongodb.queryTimeout", rootCmd.PersistentFlags().Lookup("query-timeout"))
-	viper.BindEnv("mongodb.uri", "MDBEXPORTER_MONGODB_URI")
-	viper.BindEnv("global.queryTimeout", "MDBEXPORTER_MONGODB_QUERY_TIMEOUT")
-	viper.BindEnv("log.level", "MDBEXPORTER_LOG_LEVEL")
-	viper.BindEnv("log.encoding", "MDBEXPORTER_LOG_ENCODING")
-	viper.BindEnv("bind", "MDBEXPORTER_BIND")
-	viper.BindEnv("metricsPath", "MDBEXPORTER_METRICSPATH")
+	_ = viper.BindPFlag("log.level", rootCmd.PersistentFlags().Lookup("log-level"))
+	_ = viper.BindPFlag("log.encoding", rootCmd.PersistentFlags().Lookup("log-encoding"))
+	_ = viper.BindPFlag("bind", rootCmd.PersistentFlags().Lookup("bind"))
+	_ = viper.BindPFlag("metricsPath", rootCmd.PersistentFlags().Lookup("path"))
+	_ = viper.BindPFlag("mongodb.uri", rootCmd.PersistentFlags().Lookup("uri"))
+	_ = viper.BindPFlag("mongodb.queryTimeout", rootCmd.PersistentFlags().Lookup("query-timeout"))
+	_ = viper.BindEnv("mongodb.uri", "MDBEXPORTER_MONGODB_URI")
+	_ = viper.BindEnv("global.queryTimeout", "MDBEXPORTER_MONGODB_QUERY_TIMEOUT")
+	_ = viper.BindEnv("log.level", "MDBEXPORTER_LOG_LEVEL")
+	_ = viper.BindEnv("log.encoding", "MDBEXPORTER_LOG_ENCODING")
+	_ = viper.BindEnv("bind", "MDBEXPORTER_BIND")
+	_ = viper.BindEnv("metricsPath", "MDBEXPORTER_METRICSPATH")
 }
 
 func initConfig() {

collector/collector.go

@@ -19,7 +19,6 @@ type Collector struct {
 	servers      []*server
 	logger       Logger
 	config       *Config
-	metrics      []*Metric
 	aggregations []*Aggregation
 	counter      *prometheus.CounterVec
 	cache        map[string]*cacheEntry
@@ -59,7 +58,6 @@ type Aggregation struct {
 	Pipeline   string
 	Metrics    []*Metric
 	pipeline   bson.A
-	validUntil time.Time
 }
 
 // A metric defines how a certain value is exported from a MongoDB aggregation
@@ -91,7 +89,7 @@ const (
 	ModePull = "pull"
 	//Push mode (Uses changestream which is only supported with MongoDB >= 3.6)
 	ModePush = "push"
-	//Metric generated succesfully
+	//Metric generated successfully
 	ResultSuccess = "SUCCESS"
 	//Metric value could not been determined
 	ResultError = "ERROR"
@@ -445,18 +443,17 @@ func createMetric(metric *Metric, result AggregationResult) (prometheus.Metric,
 
 func (metric *Metric) getValue(result AggregationResult) (float64, error) {
 	if val, ok := result[metric.Value]; ok {
-		switch val.(type) {
+		switch v := val.(type) {
 		case float32:
-			value := float64(val.(float32))
+			value := float64(v)
 			return value, nil
 		case float64:
-			value := val.(float64)
-			return value, nil
+			return v, nil
 		case int32:
-			value := float64(val.(int32))
+			value := float64(v)
 			return value, nil
 		case int64:
-			value := float64(val.(int64))
+			value := float64(v)
 			return value, nil
 		default:
 			return 0, fmt.Errorf("provided value taken from the aggregation result has to be a number, type %T given", val)
@@ -471,9 +468,9 @@ func (metric *Metric) getLabels(result AggregationResult) ([]string, error) {
 
 	for _, label := range metric.Labels {
 		if val, ok := result[label]; ok {
-			switch val.(type) {
+			switch v := val.(type) {
 			case string:
-				labels = append(labels, val.(string))
+				labels = append(labels, v)
 			default:
 				return labels, fmt.Errorf("provided label value taken from the aggregation result has to be a string, type %T given", val)
 			}

collector/collector_test.go

@@ -157,7 +157,7 @@ func TestInitializeMetrics(t *testing.T) {
 			aggregation: &Aggregation{
 				Metrics: []*Metric{
 					&Metric{
-						Name:          "simple_gauge_value_not_found_overriden",
+						Name:          "simple_gauge_value_not_found_overridden",
 						Type:          "gauge",
 						Help:          "overridden",
 						OverrideEmpty: true,
@@ -167,9 +167,9 @@ func TestInitializeMetrics(t *testing.T) {
 				Pipeline: "[{\"$match\":{\"foo\":\"bar\"}}]",
 			},
 			expected: `
-				# HELP simple_gauge_value_not_found_overriden overridden
-				# TYPE simple_gauge_value_not_found_overriden gauge
-				simple_gauge_value_not_found_overriden 12
+				# HELP simple_gauge_value_not_found_overridden overridden
+				# TYPE simple_gauge_value_not_found_overridden gauge
+				simple_gauge_value_not_found_overridden 12
 			`,
 		},
 		aggregationTest{