Merge pull request percona#34 from roman-vynar/http-auth

Added support for MONGODB_URI and HTTP_AUTH env vars.

README.md

@@ -25,12 +25,15 @@ The exporter can be started by running the '*mongodb_exporter*' binary that is c
 
 It is recommended to define the following options:
 
-- **-mongodb.uri** - The URI of the MongoDB port (*default: mongodb://localhost:27017*)
-- **-auth.user** - The optional exporter HTTP auth username (*default: none*)
-- **-auth.pass** - The optional exporter HTTP auth password (*default: none*)
 - **-web.listen-address** - The listen address of the exporter (*default: ":9104"*)
 - **-log_dir** - The directory to write the log file (*default: /tmp*)
 
+To define your own MongoDB URI, use environment variable `MONGODB_URI`. If set this variable takes precedence over **-mongodb.uri** flag.
+For example: `export MONGODB_URI=mongodb://localhost:27017`
+
+To enable HTTP basic authentication, set environment variable `HTTP_AUTH` to user:password pair.
+For example: `export HTTP_AUTH="user:password"`
+
 *For more options see the help page with '-h' or '--help'*
 
 If you use [MongoDB Authorization](https://docs.mongodb.org/manual/core/authorization/), you must:
@@ -48,10 +51,10 @@ db.getSiblingDB("admin").createUser({
 })
 ```
 
-2. Add the username/password to the '*-mongodb.uri*' command-line option for mongodb_exporter, example:
+2. Set environment variable `MONGODB_URI` before starting the exporter:
 
 ```
-mongodb_exporter -mongodb.uri mongodb://mongodb_exporter:s3cr3tpassw0rd@localhost:27017
+export MONGODB_URI=mongodb://mongodb_exporter:s3cr3tpassw0rd@localhost:27017
 ```
 
 ### Note about how this works

mongodb_exporter.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net/http"
 	"os"
+	"strings"
 
 	"github.com/Percona-Lab/prometheus_mongodb_exporter/collector"
 	"github.com/Percona-Lab/prometheus_mongodb_exporter/shared"
@@ -29,8 +30,6 @@ var (
 
 	mongodbURIFlag    = flag.String("mongodb.uri", mongodbDefaultUri(), "Mongodb URI, format: [mongodb://][user:pass@]host1[:port1][,host2[:port2],...][/database][?options]")
 	enabledGroupsFlag = flag.String("groups.enabled", "asserts,durability,background_flushing,connections,extra_info,global_lock,index_counters,network,op_counters,op_counters_repl,memory,locks,metrics", "Comma-separated list of groups to use, for more info see: docs.mongodb.org/manual/reference/command/serverStatus/")
-	authUserFlag      = flag.String("auth.user", "", "Username for basic auth.")
-	authPassFlag      = flag.String("auth.pass", "", "Password for basic auth.")
 )
 
 func printVersion() {
@@ -54,17 +53,25 @@ func (h *basicAuthHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	return
 }
 
-func hasUserAndPassword() bool {
-	return *authUserFlag != "" && *authPassFlag != ""
-}
-
 func prometheusHandler() http.Handler {
+	var authUser, authPass string
+	httpAuth := os.Getenv("HTTP_AUTH")
+	if httpAuth != "" {
+		data := strings.SplitN(httpAuth, ":", 2)
+		if len(data) != 2 || data[0] == "" || data[1] == "" {
+			panic("HTTP_AUTH should be formatted as user:password")
+		}
+		authUser = data[0]
+		authPass = data[1]
+		fmt.Println("HTTP basic authentication is enabled")
+	}
+
 	handler := prometheus.Handler()
-	if hasUserAndPassword() {
+	if authUser != "" &&  authPass != "" {
 		handler = &basicAuthHandler{
-			handler:  prometheus.Handler().ServeHTTP,
-			user:     *authUserFlag,
-			password: *authPassFlag,
+			handler:  handler.ServeHTTP,
+			user:     authUser,
+			password: authPass,
 		}
 	}
 
@@ -73,12 +80,18 @@ func prometheusHandler() http.Handler {
 
 func startWebServer() {
 	printVersion()
-	fmt.Printf("Listening on %s\n", *listenAddressFlag)
+
+	uri := os.Getenv("MONGODB_URI")
+	if uri != "" {
+		mongodbURIFlag = &uri
+	}
+
 	handler := prometheusHandler()
 
 	registerCollector()
 
 	http.Handle(*metricsPathFlag, handler)
+	fmt.Printf("Listening on %s\n", *listenAddressFlag)
 	err := http.ListenAndServe(*listenAddressFlag, nil)
 
 	if err != nil {