Add TLS metrics support (#175)

README.md

@@ -375,3 +375,43 @@ Requires Go 1.13 installed.
 ```
 make
 ```
+
+## Exposing metrics through HTTPS
+
+web-config.yml
+```
+# Minimal TLS configuration example. Additionally, a certificate and a key file
+# are needed.
+tls_server_config:
+  cert_file: server.crt
+  key_file: server.key
+```
+Running
+```
+$ ./process-exporter -web.config.file web-config.yml &
+$ curl -sk https://localhost:9256/metrics | grep process
+
+# HELP namedprocess_scrape_errors general scrape errors: no proc metrics collected during a cycle
+# TYPE namedprocess_scrape_errors counter
+namedprocess_scrape_errors 0
+# HELP namedprocess_scrape_partial_errors incremented each time a tracked proc's metrics collection fails partially, e.g. unreadable I/O stats
+# TYPE namedprocess_scrape_partial_errors counter
+namedprocess_scrape_partial_errors 0
+# HELP namedprocess_scrape_procread_errors incremented each time a proc's metrics collection fails
+# TYPE namedprocess_scrape_procread_errors counter
+namedprocess_scrape_procread_errors 0
+# HELP process_cpu_seconds_total Total user and system CPU time spent in seconds.
+# TYPE process_cpu_seconds_total counter
+process_cpu_seconds_total 0.21
+# HELP process_exporter_build_info A metric with a constant '1' value labeled by version, revision, branch, and goversion from which process_exporter was built.
+# TYPE process_exporter_build_info gauge
+process_exporter_build_info{branch="",goversion="go1.17.3",revision="",version=""} 1
+# HELP process_max_fds Maximum number of open file descriptors.
+# TYPE process_max_fds gauge
+process_max_fds 1.048576e+06
+# HELP process_open_fds Number of open file descriptors.
+# TYPE process_open_fds gauge
+process_open_fds 10
+```
+
+For further information about TLS configuration, please visit: [exporter-toolkit](https://github.com/prometheus/exporter-toolkit/blob/master/docs/web-configuration.md)

cmd/process-exporter/main.go

@@ -17,7 +17,9 @@ import (
 	"github.com/ncabatoff/process-exporter/config"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/prometheus/common/promlog"
 	promVersion "github.com/prometheus/common/version"
+	"github.com/prometheus/exporter-toolkit/web"
 )
 
 // Version is set at build time use ldflags.
@@ -166,6 +168,8 @@ func main() {
 			"print manual")
 		configPath = flag.String("config.path", "",
 			"path to YAML config file")
+		tlsConfigFile = flag.String("web.config.file", "",
+			"path to YAML web config file")
 		recheck = flag.Bool("recheck", false,
 			"recheck process names on each scrape")
 		debug = flag.Bool("debug", false,
@@ -175,6 +179,9 @@ func main() {
 	)
 	flag.Parse()
 
+	promlogConfig := &promlog.Config{}
+	logger := promlog.New(promlogConfig)
+
 	if *showVersion {
 		fmt.Printf("%s\n", promVersion.Print("process-exporter"))
 		os.Exit(0)
@@ -263,7 +270,9 @@ func main() {
 			</body>
 			</html>`))
 	})
-	if err := http.ListenAndServe(*listenAddress, nil); err != nil {
-		log.Fatalf("Unable to setup HTTP server: %v", err)
+	server := &http.Server{Addr: *listenAddress}
+	if err := web.ListenAndServe(server, *tlsConfigFile, logger); err != nil {
+		log.Fatalf("Failed to start the server: %v", err)
+		os.Exit(1)
 	}
 }