Skeleton collector with Prometheus endpoint 5/6

cmd/collector/collector_test.go

@@ -0,0 +1,21 @@
+package collector
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"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
+}
+

cmd/collector/go.mod

@@ -0,0 +1,16 @@
+module memory-collector
+
+go 1.22.9
+
+require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/klauspost/compress v1.17.9 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // 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
+	golang.org/x/sys v0.22.0 // indirect
+	google.golang.org/protobuf v1.34.2 // indirect
+)

cmd/collector/go.sum

@@ -0,0 +1,20 @@
+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/klauspost/compress v1.17.9 h1:6KIumPrER1LHsvBVuDa0r5xaG0Es51mhhB9BQB2qeMA=
+github.com/klauspost/compress v1.17.9/go.mod h1:Di0epgTjJY877eYKx5yC51cX2A2Vl2ibi7bDH9ttBbw=
+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/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=
+github.com/prometheus/client_model v0.6.1/go.mod h1:OrxVMOVHjw3lKMa8+x6HeMGkHMQyHDk9E3jmP2AmGiY=
+github.com/prometheus/common v0.55.0 h1:KEi6DK7lXW/m7Ig5i47x0vRzuBsHuvJdi5ee6Y3G1dc=
+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=
+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=

cmd/collector/main.go

@@ -0,0 +1,29 @@
+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()
+
+	http.Handle("/metrics", promhttp.Handler())
+	http.ListenAndServe(":2112", nil)
+}
+

docs/devlog.md

@@ -0,0 +1,91 @@
+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
+
+Initial environment and tools:
+```
+# Shell: Bash
+distrobox create --image fedora:40 --name memory-collector 
+distrobox enter memory-collector
+sudo dnf install git go
+
+# cd to preferred project directory
+# Clone (fork of) project
+git clone https://github.com/perfpod/memory-collector
+cd memory-collector
+```
+
+Issue 19 objective 1: Create a `main.go` file in `cmd/collector`
+```
+mkdir -p cmd/collector
+cd cmd/collector
+touch main.go
+```
+
+- Prometheus client_golang reference guide: https://prometheus.io/docs/guides/go-application/
+- Go package installation reference: https://go.dev/doc/go-get-install-deprecation
+- Go Module reference: https://go.dev/ref/mod#go-mod-init
+- `go get` and `go install` require a Go Module and/or @version tag as of Go 1.17 in August 2021
+- Prometheus go_client installation instructions appear to be outdated and missing a piece
+- Submitted issue to Prometheus documentation repository: https://github.com/prometheus/docs/issues/2556#issue-2736636166
+- Proceeded with Prometheus client_golang guide 
+```
+cd cmd/collector
+go mod init memory-collector
+go get github.com/prometheus/client_golang/prometheus
+go get github.com/prometheus/client_golang/prometheus/promauto
+go get github.com/prometheus/client_golang/prometheus/promhttp
+```
+
+Issue 19 objective 2: Expose an endpoint on a known fixed port 
+```
+# Wrote and tested example Go exposition application from Prometheus guide
+go run main.go &
+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()
+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)
+```
+
+Issue 19 objective 4: Manually verify: query the endpoint using `curl` or `wget`
+```
+curl -s http://localhost:2112/metrics | grep up_metric
+```
+Output:
+```
+# 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
+```
+
+Issue 19 objective 5: Move the code into a function (not `main()`)
+```
+# Moved Up metric into "func recordMetrics()" and added function call in main()
+
+func main() {
+	recordMetrics()
+	
+	http.Handle("/metrics", promhttp.Handler())
+	http.ListenAndServe(":2112", nil)
+}
+
+# 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
+