Allow to specify no targets

In order to query only rate limits. Querying targets reduces
the remaining rate limits. This should be avoided if the rate limit
is the only information of interest.

Author: adebasi

README.md

@@ -6,17 +6,12 @@ Exposes basic metrics for your repositories from the GitHub API, to a Prometheus
 
 ## Configuration
 
-This exporter is setup to take input from environment variables:
+This exporter is setup to take input from environment variables. All variables are optional:
 
-### Required
 * `ORGS` If supplied, the exporter will enumerate all repositories for that organization. Expected in the format "org1, org2".
 * `REPOS` If supplied, The repos you wish to monitor, expected in the format "user/repo1, user/repo2". Can be across different Github users/orgs.
 * `USERS` If supplied, the exporter will enumerate all repositories for that users. Expected in
 the format "user1, user2".
-
-At least one of those 3 options should be provided.
-
-### Optional
 * `GITHUB_TOKEN` If supplied, enables the user to supply a github authentication token that allows the API to be queried more often. Optional, but recommended.
 * `GITHUB_TOKEN_FILE` If supplied _instead of_ `GITHUB_TOKEN`, enables the user to supply a path to a file containing a github authentication token that allows the API to be queried more often. Optional, but recommended.
 * `API_URL` Github API URL, shouldn't need to change this. Defaults to `https://api.github.com`

config/config.go

@@ -65,9 +65,8 @@ func getScrapeURLs(apiURL, repos, orgs, users string) ([]string, error) {
 
 	opts := "?&per_page=100" // Used to set the Github API to return 100 results per page (max)
 
-	// User input validation, check that either repositories or organisations have been passed in
 	if len(repos) == 0 && len(orgs) == 0 && len(users) == 0 {
-		return urls, fmt.Errorf("No targets specified")
+		log.Info("No targets specified. Only rate limit endpoint will be scraped")
 	}
 
 	// Append repositories to the array

exporter/gather.go

@@ -10,14 +10,14 @@ import (
 )
 
 // gatherData - Collects the data from the API and stores into struct
-func (e *Exporter) gatherData() ([]*Datum, *RateLimits, error) {
+func (e *Exporter) gatherData() ([]*Datum, error) {
 
 	data := []*Datum{}
 
 	responses, err := asyncHTTPGets(e.TargetURLs, e.APIToken)
 
 	if err != nil {
-		return data, nil, err
+		return data, err
 	}
 
 	for _, response := range responses {
@@ -46,26 +46,19 @@ func (e *Exporter) gatherData() ([]*Datum, *RateLimits, error) {
 		log.Infof("API data fetched for repository: %s", response.url)
 	}
 
-	// Check the API rate data and store as a metric
-	rates, err := getRates(e.APIURL, e.APIToken)
-
-	if err != nil {
-		log.Errorf("Unable to obtain rate limit data from API, Error: %s", err)
-	}
-
 	//return data, rates, err
-	return data, rates, nil
+	return data, nil
 
 }
 
 // getRates obtains the rate limit data for requests against the github API.
 // Especially useful when operating without oauth and the subsequent lower cap.
-func getRates(baseURL string, token string) (*RateLimits, error) {
+func (e *Exporter) getRates() (*RateLimits, error) {
 
 	rateEndPoint := ("/rate_limit")
-	url := fmt.Sprintf("%s%s", baseURL, rateEndPoint)
+	url := fmt.Sprintf("%s%s", e.APIURL, rateEndPoint)
 
-	resp, err := getHTTPResponse(url, token)
+	resp, err := getHTTPResponse(url, e.APIToken)
 	if err != nil {
 		return &RateLimits{}, err
 	}

exporter/prometheus.go

@@ -18,11 +18,20 @@ func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
 // This function is called when a scrape is peformed on the /metrics page
 func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 
+	data := []*Datum{}
+	var err error
 	// Scrape the Data from Github
-	var data, rates, err = e.gatherData()
+	if len(e.TargetURLs) > 0 {
+		data, err = e.gatherData()
+		if err != nil {
+			log.Errorf("Error gathering Data from remote API: %v", err)
+			return
+		}
+	}
 
+	rates, err := e.getRates()
 	if err != nil {
-		log.Errorf("Error gathering Data from remote API: %v", err)
+		log.Errorf("Error gathering Rates from remote API: %v", err)
 		return
 	}