feat: Added GitHub app authentication

.gitignore

@@ -1,4 +1,4 @@
 .sequence
-
+*.pem
 .idea/
 .vscode/

README.md

@@ -14,6 +14,11 @@ This exporter is setup to take input from environment variables. All variables a
 the format "user1, user2".
 * `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.
+* `GITHUB_APP` If true , authenticates ass GitHub app to the API.
+* `GITHUB_APP_ID` The APP ID of the GitHub App.
+* `GITHUB_APP_INSTALLATION_ID` The INSTALLATION ID of the GitHub App.
+* `GITHUB_APP_KEY_PATH` The path to the github private key.
+* `GITHUB_RATE_LIMIT` The RATE LIMIT that suppose to be for github app (default is 15,000). If the exporter sees the value is below this variable it generating new token for the app.
 * `API_URL` Github API URL, shouldn't need to change this. Defaults to `https://api.github.com`
 * `LISTEN_PORT` The port you wish to run the container on, the Dockerfile defaults this to `9171`
 * `METRICS_PATH` the metrics URL path you wish to use, defaults to `/metrics`
@@ -27,10 +32,14 @@ Run manually from Docker Hub:
 docker run -d --restart=always -p 9171:9171 -e REPOS="infinityworks/ranch-eye, infinityworks/prom-conf" infinityworks/github-exporter
 ```
 
+Run manually from Docker Hub (With GitHub App):
+```
+docker run -d --restart=always -p 9171:9171 --read-only -v ./key.pem:/key.pem -e GITHUB_APP=true -e GITHUB_APP_ID= -e GITHUB_APP_INSTALLATION_ID= -e GITHUB_APP_KEY_PATH=/key.pem <IMAGE_NAME>
+```
+
 Build a docker image:
 ```
 docker build -t <image-name> .
-docker run -d --restart=always -p 9171:9171 -e REPOS="infinityworks/ranch-eye, infinityworks/prom-conf" <image-name>
 ```
 
 ## Docker compose
@@ -47,6 +56,29 @@ github-exporter:
     environment:
       - REPOS=<REPOS you want to monitor>
       - GITHUB_TOKEN=<your github api token>
+```
+
+## Docker compose (GitHub App)
+
+```
+github-exporter-github-app:
+  tty: true
+  stdin_open: true
+  expose:
+    - 9171
+  ports:
+    - 9171:9171
+  build: .
+  environment:
+    - LOG_LEVEL=debug
+    - LISTEN_PORT=9171
+    - GITHUB_APP=true
+    - GITHUB_APP_ID=
+    - GITHUB_APP_INSTALLATION_ID=
+    - GITHUB_APP_KEY_PATH=/key.pem
+  restart: unless-stopped
+  volumes:
+    - "./key.pem:/key.pem:ro"
 
 ```
 

config/config.go

@@ -1,11 +1,15 @@
 package config
 
 import (
+	"context"
 	"io/ioutil"
+	"net/http"
 	"net/url"
 	"path"
+	"strconv"
 	"strings"
 
+	"github.com/bradleyfalzon/ghinstallation"
 	log "github.com/sirupsen/logrus"
 
 	"os"
@@ -22,6 +26,7 @@ type Config struct {
 	users         []string
 	apiToken      string
 	targetURLs    []string
+	gitHubApp     bool
 }
 
 // Init populates the Config struct based on environmental runtime configuration
@@ -39,6 +44,7 @@ func Init() Config {
 		nil,
 		"",
 		nil,
+		false,
 	}
 
 	err := appConfig.SetAPIURL(cfg.GetEnv("API_URL", "https://api.github.com"))
@@ -57,6 +63,15 @@ func Init() Config {
 	if users != "" {
 		appConfig.SetUsers(strings.Split(users, ", "))
 	}
+
+	gitHubApp := os.Getenv("GITHUB_APP")
+	if gitHubApp == "true" {
+		gitHubAppKeyPath := os.Getenv("GITHUB_APP_KEY_PATH")
+		gitHubAppId, _ := strconv.ParseInt(os.Getenv("GITHUB_APP_ID"), 10, 64)
+		gitHubAppInstalaltionId, _ := strconv.ParseInt(os.Getenv("GITHUB_APP_INSTALLATION_ID"), 10, 64)
+		appConfig.SetAPITokenFromGitHubApp(gitHubAppId, gitHubAppInstalaltionId, gitHubAppKeyPath)
+	}
+
 	tokenEnv := os.Getenv("GITHUB_TOKEN")
 	tokenFile := os.Getenv("GITHUB_TOKEN_FILE")
 	if tokenEnv != "" {
@@ -67,7 +82,6 @@ func Init() Config {
 			log.Errorf("Error initialising Configuration, Error: %v", err)
 		}
 	}
-
 	return appConfig
 }
 
@@ -126,6 +140,20 @@ func (c *Config) SetAPITokenFromFile(tokenFile string) error {
 	return nil
 }
 
+// SetAPITokenFromGitHubApp generating api token from github app configuration.
+func (c *Config) SetAPITokenFromGitHubApp(gitHubAppId int64, gitHubAppInstalaltionId int64, gitHubAppKeyPath string) error {
+	itr, err := ghinstallation.NewKeyFromFile(http.DefaultTransport, gitHubAppId, gitHubAppInstalaltionId, gitHubAppKeyPath)
+	if err != nil {
+		return err
+	}
+	strToken, err := itr.Token(context.Background())
+	if err != nil {
+		return err
+	}
+	c.SetAPIToken(strToken)
+	return nil
+}
+
 // Init populates the Config struct based on environmental runtime configuration
 // All URL's are added to the TargetURL's string array
 func (c *Config) setScrapeURLs() error {

exporter/prometheus.go

@@ -1,6 +1,15 @@
 package exporter
 
 import (
+	"context"
+	"errors"
+	"net/http"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+
+	"github.com/bradleyfalzon/ghinstallation"
 	"github.com/prometheus/client_golang/prometheus"
 	log "github.com/sirupsen/logrus"
 )
@@ -17,9 +26,20 @@ func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
 // Collect function, called on by Prometheus Client library
 // 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
+
+	gitHubApp := os.Getenv("GITHUB_APP")
+	if strings.ToLower(gitHubApp) == "true" {
+		needReAuth, err := e.isTokenExpired()
+		if err != nil {
+			log.Errorf("Error checking token expiration status: %v", err)
+			return
+		}
+		if needReAuth {
+			e.reAuth()
+		}
+	}
 	// Scrape the Data from Github
 	if len(e.TargetURLs()) > 0 {
 		data, err = e.gatherData()
@@ -46,3 +66,55 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 	log.Info("All Metrics successfully collected")
 
 }
+
+func (e *Exporter) isTokenExpired() (bool, error) {
+	u := *e.APIURL()
+	u.Path = path.Join(u.Path, "rate_limit")
+
+	resp, err := getHTTPResponse(u.String(), e.APIToken())
+
+	if err != nil {
+		return false, err
+	}
+	defer resp.Body.Close()
+	// Triggers if rate-limiting isn't enabled on private Github Enterprise installations
+	if resp.StatusCode == 404 {
+		return false, errors.New("404 Error")
+	}
+
+	limit, err := strconv.ParseFloat(resp.Header.Get("X-RateLimit-Limit"), 64)
+
+	if err != nil {
+		return false, err
+	}
+
+	defaultLimit := os.Getenv("GITHUB_RATE_LIMIT")
+	if len(defaultLimit) == 0 {
+		defaultLimit = "15000"
+	}
+	defaultLimitInt, err := strconv.ParseInt(defaultLimit, 10, 64)
+	if err != nil {
+		return false, err
+	}
+	if limit < float64(defaultLimitInt) {
+		return true, nil
+	}
+	return false, nil
+
+}
+
+func (e *Exporter) reAuth() error {
+	gitHubAppKeyPath := os.Getenv("GITHUB_APP_KEY_PATH")
+	gitHubAppId, _ := strconv.ParseInt(os.Getenv("GITHUB_APP_ID"), 10, 64)
+	gitHubAppInstalaltionId, _ := strconv.ParseInt(os.Getenv("GITHUB_APP_INSTALLATION_ID"), 10, 64)
+	itr, err := ghinstallation.NewKeyFromFile(http.DefaultTransport, gitHubAppId, gitHubAppInstalaltionId, gitHubAppKeyPath)
+	if err != nil {
+		return err
+	}
+	strToken, err := itr.Token(context.Background())
+	if err != nil {
+		return err
+	}
+	e.Config.SetAPIToken(strToken)
+	return nil
+}

go.mod

@@ -3,6 +3,7 @@ module github.com/infinityworks/github-exporter
 go 1.19
 
 require (
+	github.com/bradleyfalzon/ghinstallation v1.1.1
 	github.com/infinityworks/go-common v0.0.0-20170820165359-7f20a140fd37
 	github.com/prometheus/client_golang v1.14.0
 	github.com/sirupsen/logrus v1.9.0
@@ -14,14 +15,18 @@ require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/dgrijalva/jwt-go v3.2.0+incompatible // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/go-github/v29 v29.0.2 // indirect
+	github.com/google/go-querystring v1.0.0 // indirect
 	github.com/kr/pretty v0.3.1 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_model v0.3.0 // indirect
 	github.com/prometheus/common v0.39.0 // indirect
 	github.com/prometheus/procfs v0.9.0 // indirect
 	github.com/stretchr/testify v1.8.0 // indirect
+	golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2 // indirect
 	golang.org/x/sys v0.4.0 // indirect
 	google.golang.org/protobuf v1.28.1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -1,18 +1,28 @@
 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/bradleyfalzon/ghinstallation v1.1.1 h1:pmBXkxgM1WeF8QYvDLT5kuQiHMcmf+X015GI0KM/E3I=
+github.com/bradleyfalzon/ghinstallation v1.1.1/go.mod h1:vyCmHTciHx/uuyN82Zc3rXN3X2KTK8nUTCrTMwAhcug=
 github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
 github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumCAMpl/TFQ4/5kLM=
+github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.5/go.mod h1:6O5/vntMXwX2lRkT1hjjk0nAC1IDOTvTlVgjlRvqsdk=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/golang/protobuf v1.5.2 h1:ROPKBNFfQgOUMifHyP+KYbvpjbdoFNs+aK7DXlji0Tw=
 github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
+github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-github/v29 v29.0.2 h1:opYN6Wc7DOz7Ku3Oh4l7prmkOMwEcQxpFtxdU8N8Pts=
+github.com/google/go-github/v29 v29.0.2/go.mod h1:CHKiKKPHJ0REzfwc14QMklvtHwCveD0PxlMjLlzAM5E=
+github.com/google/go-querystring v1.0.0 h1:Xkwi/a1rcvNg1PPYe5vI8GbeBY/jrVuDX5ASuANWTrk=
+github.com/google/go-querystring v1.0.0/go.mod h1:odCYkC5MyYFN7vkCjXpyrEuKhc/BUO6wN/zVPAxq5ck=
 github.com/infinityworks/go-common v0.0.0-20170820165359-7f20a140fd37 h1:Lm6kyC3JBiJQvJrus66He0E4viqDc/m5BdiFNSkIFfU=
 github.com/infinityworks/go-common v0.0.0-20170820165359-7f20a140fd37/go.mod h1:+OaHNKQvQ9oOCr+DgkF95PkiDx20fLHpzMp8SmRPQTg=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
@@ -47,11 +57,18 @@ github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PK
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/tomnomnom/linkheader v0.0.0-20180905144013-02ca5825eb80 h1:nrZ3ySNYwJbSpD6ce9duiP+QkD3JuLCcWkdaehUS/3Y=
 github.com/tomnomnom/linkheader v0.0.0-20180905144013-02ca5825eb80/go.mod h1:iFyPdL66DjUD96XmzVL3ZntbzcflLnznH0fr99w5VqE=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2 h1:VklqNMn3ovrHsnt90PveolxSbWFaJdECFbxSq0Mqo2M=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.4.0 h1:Zr2JFtRQNX3BCZ8YtxRE9hNJYC8J6I1MVbMg6owUp18=
 golang.org/x/sys v0.4.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
 google.golang.org/protobuf v1.28.1 h1:d0NfwRgPtno5B1Wa6L2DAG+KivqkdutMf1UhdNx175w=