Merge pull request #27 from atimeofday/main

Add integration test to Prometheus endpoint

cmd/collector/collector_test.go

@@ -1,4 +1,4 @@
-package collector
+package main
 
 import (
 	"fmt"
@@ -10,12 +10,40 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// TODO
-func TestMetricsUp() {
-	// testutil.ScrapeAndCompare()
-	// "http://localhost:2112/metrics"
-	// # HELP perfpod_memory_collector_up_metric Test metric to confirm skeleton application functionality.
-	// # TYPE perfpod_memory_collector_up_metric gauge
-	// perfpod_memory_collector_up_metric 1
-}
 
+func TestMetricsUp(t *testing.T) {
+
+	// Initialize module/server for standalone integration test
+	go main()
+	time.Sleep(1 * time.Second)
+
+	// Set values for standalone integration test
+	serverURL := "http://localhost:2112"
+	metricName := "perfpod_memory_collector_up_metric"
+	metricHelpText := "Test metric to confirm skeleton application functionality."
+	metricType := "gauge"
+	expectedMetricValue := 1
+
+	// Check for test result every 100 milliseconds with a 1 second limit
+	require.Eventuallyf(t, func() bool {
+
+		// Exact multiline metric template required by testutil.ScrapeAndCompare:
+
+		// # HELP perfpod_memory_collector_up_metric Test metric to confirm skeleton application functionality.
+		// # TYPE perfpod_memory_collector_up_metric gauge
+		// perfpod_memory_collector_up_metric 1
+
+		// Generalized metric template
+		expected := fmt.Sprintf("\n# HELP %s %s\n# TYPE %s %s\n%s %d\n", metricName, metricHelpText, metricName, metricType, metricName, expectedMetricValue)
+
+		// Check current server metrics against expected string/value
+		if err := testutil.ScrapeAndCompare(serverURL+"/metrics", strings.NewReader(expected), metricName); err == nil {
+		    return true
+
+		// Returns an error and error message if the expected string/value is not found
+		} else {
+			t.Log(err.Error())
+			return false
+		}
+	}, time.Second, 100*time.Millisecond, "Could not find metric %s with value %d", metricName, expectedMetricValue)
+}

cmd/collector/go.mod

@@ -5,12 +5,17 @@ go 1.22.9
 require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/klauspost/compress v1.17.9 // indirect
+	github.com/kylelemons/godebug v1.1.0 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_golang v1.20.5 // indirect
 	github.com/prometheus/client_model v0.6.1 // indirect
 	github.com/prometheus/common v0.55.0 // indirect
 	github.com/prometheus/procfs v0.15.1 // indirect
+	github.com/stretchr/testify v1.10.0 // indirect
 	golang.org/x/sys v0.22.0 // indirect
 	google.golang.org/protobuf v1.34.2 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

cmd/collector/go.sum

@@ -2,10 +2,16 @@ github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/klauspost/compress v1.17.9 h1:6KIumPrER1LHsvBVuDa0r5xaG0Es51mhhB9BQB2qeMA=
 github.com/klauspost/compress v1.17.9/go.mod h1:Di0epgTjJY877eYKx5yC51cX2A2Vl2ibi7bDH9ttBbw=
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_golang v1.20.5 h1:cxppBPuYhUnsO6yo/aoRol4L7q7UFfdm+bR9r+8l63Y=
 github.com/prometheus/client_golang v1.20.5/go.mod h1:PIEt8X02hGcP8JWbeHyeZ53Y/jReSnHgO035n//V5WE=
 github.com/prometheus/client_model v0.6.1 h1:ZKSh/rekM+n3CeS952MLRAdFwIKqeY8b62p8ais2e9E=
@@ -14,7 +20,12 @@ github.com/prometheus/common v0.55.0 h1:KEi6DK7lXW/m7Ig5i47x0vRzuBsHuvJdi5ee6Y3G
 github.com/prometheus/common v0.55.0/go.mod h1:2SECS4xJG1kd8XF9IcM1gMX6510RAEL65zxzNImwdc8=
 github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0learggepc=
 github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
 golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 google.golang.org/protobuf v1.34.2 h1:6xV6lTsCfpGD21XK49h7MhtcApnLqkfYgPcdHftf6hg=
 google.golang.org/protobuf v1.34.2/go.mod h1:qYOHts0dSfpeUzUFpOMr/WGzszTmLH+DiWniOlNbLDw=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

cmd/collector/main.go

@@ -2,26 +2,12 @@ package main
 
 import (
 	"net/http"
-
-	"github.com/prometheus/client_golang/prometheus"
-	// "github.com/prometheus/client_golang/prometheus/promauto"
     "github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
-func recordMetrics() {
-	upMetric := prometheus.NewGauge(prometheus.GaugeOpts{
-			Namespace: 	"perfpod",
-			Subsystem: 	"memory_collector",
-			Name: 		"up_metric",
-			Help: 		"Test metric to confirm skeleton application functionality.",
-		})
-		prometheus.MustRegister(upMetric)
-
-		upMetric.Set(1)
-}
 
 func main() {
-	recordMetrics()
+	go recordMetrics()
 
 	http.Handle("/metrics", promhttp.Handler())
 	http.ListenAndServe(":2112", nil)

cmd/collector/record_metrics.go

@@ -0,0 +1,18 @@
+package main
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+
+func recordMetrics() {
+	upMetric := prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: 	"perfpod",
+			Subsystem: 	"memory_collector",
+			Name: 		"up_metric",
+			Help: 		"Test metric to confirm skeleton application functionality.",
+		})
+		prometheus.MustRegister(upMetric)
+
+		upMetric.Set(1)
+}

docs/devlog.md

@@ -1,8 +1,8 @@
 Documentation of development steps, environment, and dependencies  
 
-Contributors: atimeofday;
-Goals: Create skeleton collector with Prometheus endpoint;
-Issues: https://github.com/perfpod/memory-collector/issues/19
+- Contributors: atimeofday
+- Goals: Create skeleton collector with Prometheus endpoint
+- Issues: https://github.com/perfpod/memory-collector/issues/19
 
 Initial environment and tools:
 ```
@@ -48,7 +48,8 @@ curl http://localhost:2112/metrics
 
 Issue 19 objective 3: Expose the `up` metric with value 1
 ```
-# Created, registered, and set an 'up' metric in func main()
+// Created, registered, and set an 'up' metric in func main()
+
 upMetric := prometheus.NewGauge(prometheus.GaugeOpts{
 	Namespace: 	"perfpod",
 	Subsystem: 	"memory_collector",
@@ -73,7 +74,7 @@ perfpod_memory_collector_up_metric 1
 
 Issue 19 objective 5: Move the code into a function (not `main()`)
 ```
-# Moved Up metric into "func recordMetrics()" and added function call in main()
+// Moved Up metric into "func recordMetrics()" and added function call in main()
 
 func main() {
 	recordMetrics()
@@ -82,10 +83,90 @@ func main() {
 	http.ListenAndServe(":2112", nil)
 }
 
-# Repeated manual verification endpoint query
+// Repeated manual verification endpoint query
 ```
 
 Issue 19 objective 6: Add an integration test that verifies the metrics are up, using client_golang's testutil
 - TO DO
 - May require assistance
 
+---
+
+- Issue 19 split into 5/5 done and new Issue 20
+- Issue 19 5/5 PR opened and merged
+
+---
+
+- Contributors: atimeofday
+- Goals: Add integration test to Prometheus endpoint
+- Issues: https://github.com/perfpod/memory-collector/issues/20
+
+Research & references:
+```
+https://go.dev/doc/tutorial/add-a-test
+https://albertmoreno.dev/posts/testing-prometheus-metrics-in-integration-tests-in-golang/
+https://github.com/prometheus/client_golang/blob/main/prometheus/testutil/testutil.go
+https://github.com/prometheus/client_golang/blob/main/prometheus/testutil/testutil_test.go
+```
+
+```
+go get github.com/prometheus/client_golang/prometheus/testutil 
+go get github.com/stretchr/testify/require
+```
+
+Go test format:
+```
+[filename]_test.go
+
+import(
+	[...]
+)
+
+func [TestFunction](t *testing.T) {
+	// Set test values
+	// Perform test
+}
+
+// Perform more tests
+```
+
+1. Created skeleton test based on examples 
+
+```
+func TestMetricsUp(t *testing.T) {
+	require.Eventuallyf(t, func() bool {
+
+  		// Test values
+  		// ??? expected format
+
+		if err := testutil.ScrapeAndCompare(serverURL+"/metrics", strings.NewReader(expected), metricName); err == nil {
+		    return true
+		} else {
+			t.Log(err.Error())
+			return false
+		}
+	}, time.Second, 100*time.Millisecond, "Could not find metric %s with value %d", metricName, expectedMetricValue)
+}
+```
+
+2. Checked the implementation of the testutil ScrapeAndCompare function, and notably, the implementation of its own integration test.
+3. Located and implemented the exact input template required by the function, then implemented generalized code for the template.
+4. Researched goroutines to allow automatically initializing the (currently local) remote server to be tested.
+
+```
+go main()
+time.Sleep(1 * time.Second)
+```
+
+5. Refined logical flow from example code for improved readability.
+
+---
+
+- Issue 20 done
+
+---
+
+- Contributors: 
+- Goals: 
+- Issues: 
+