Fixes #4

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.7 AS build
+FROM golang:1.8 AS build
 ADD . /src
 WORKDIR /src
 RUN go get -t github.com/stretchr/testify/suite
@@ -14,7 +14,8 @@ ENV GLOBAL_SCRAPE_INTERVAL=10s \
     ARG_CONFIG_FILE=/etc/prometheus/prometheus.yml \
     ARG_STORAGE_LOCAL_PATH=/prometheus \
     ARG_WEB_CONSOLE_LIBRARIES=/usr/share/prometheus/console_libraries \
-    ARG_WEB_CONSOLE_TEMPLATES=/usr/share/prometheus/consoles
+    ARG_WEB_CONSOLE_TEMPLATES=/usr/share/prometheus/consoles \
+    CONFIGS_DIR="/run/secrets"
 
 EXPOSE 8080
 

docs/config.md

@@ -71,4 +71,6 @@ Please consult [Prometheus Configuration](https://prometheus.io/docs/operating/c
 
 ## Scrapes
 
-Content of Docker secrets prefixed with the name `scrape_` is automatically added to the `scrape_configs` section of the configuration.
+Additional scrapes can be added through files prefixed with `scrape_`. By default, all such files located in `/run/secrets` are automatically added to the `scrape_configs` section of the configuration. The directory can be changed by setting a different value to the environment variable `CONFIGS_DIR`.
+
+The simplest way to add scrape configs is to use Docker [secrets](https://docs.docker.com/engine/swarm/secrets/) or [configs](https://docs.docker.com/engine/swarm/configs/).

prometheus/config.go

@@ -26,7 +26,7 @@ global:`
 }
 
 func GetScrapeConfig(scrapes map[string]Scrape) string {
-	config := getScrapeConfigFromMap(scrapes) + getScrapeConfigFromSecrets()
+	config := getScrapeConfigFromMap(scrapes) + getScrapeConfigFromDir()
 	if len(config) > 0 {
 		if !strings.HasPrefix(config, "\n") {
 			config = "\n" + config
@@ -73,14 +73,21 @@ func getGlobalConfigData() map[string]map[string]string {
 	return data
 }
 
-func getScrapeConfigFromSecrets() string {
+func getScrapeConfigFromDir() string {
 	config := ""
-	if files, err := afero.ReadDir(FS, "/run/secrets/"); err == nil {
+	dir := "/run/secrets/"
+	if len(os.Getenv("CONFIGS_DIR")) > 0 {
+		dir = os.Getenv("CONFIGS_DIR")
+	}
+	if !strings.HasSuffix(dir, "/") {
+		dir += "/"
+	}
+	if files, err := afero.ReadDir(FS, dir); err == nil {
 		for _, file := range files {
 			if !strings.HasPrefix(file.Name(), "scrape_") {
 				continue
 			}
-			if content, err := afero.ReadFile(FS, "/run/secrets/" + file.Name()); err == nil {
+			if content, err := afero.ReadFile(FS, dir + file.Name()); err == nil {
 				config += string(content)
 				if !strings.HasSuffix(config, "\n") {
 					config += "\n"

prometheus/config_test.go

@@ -157,6 +157,31 @@ scrape_configs:
 	s.Equal(expected, actual)
 }
 
+func (s *ConfigTestSuite) Test_GetScrapeConfig_ReturnsConfigsFromCustomDirectory() {
+	fsOrig := FS
+	defer func() { FS = fsOrig }()
+	FS = afero.NewMemMapFs()
+	defer func() { os.Unsetenv("CONFIGS_DIR") }()
+	os.Setenv("CONFIGS_DIR", "/tmp")
+	job := `  - job_name: "my-service"
+    dns_sd_configs:
+      - names: ["tasks.my-service"]
+        type: A
+        port: 5678`
+	expected := fmt.Sprintf(`
+scrape_configs:
+%s
+`,
+		job,
+	)
+	scrapes := map[string]Scrape {}
+	afero.WriteFile(FS, "/tmp/scrape_job", []byte(job), 0644)
+
+	actual := GetScrapeConfig(scrapes)
+
+	s.Equal(expected, actual)
+}
+
 func (s *ConfigTestSuite) Test_GetScrapeConfig_ReturnsEmptyString_WhenNoData() {
 	actual := GetScrapeConfig(map[string]Scrape{})