Merge branch 'fix/1-initial-release' into 'master'

Initial release

Closes #1

See merge request !1

README.md

 # GitLab Runner Droplet Monitor [![pipeline status](https://git.ethitter.com/debian/gitlab-runner-do-monitor/badges/master/pipeline.svg)](https://git.ethitter.com/debian/gitlab-runner-do-monitor/commits/master)
 
-Monitor Digital Ocean for stale droplets created by GitLab Runner
\ No newline at end of file
+Monitor Digital Ocean for stale droplets created by GitLab Runner
+
+## Configuration
+
+```json
+{
+  "log-dest": "os.Stdout",
+  "api-key": "",
+  "threshold": 5400,
+  "delete-stale": true
+}
+
+```
+
+* `log-dest`: set to a path to write to a log file, otherwise `os.Stdout`
+* `api-key`: Digital Ocean Personal Access Token
+* `threshold`: time, in seconds, after which to consider a runner stale
+* `delete-stale`: whether to delete stale runners, in addition to reporting them
+
+##### A note about `threshold`
+
+This value needs to be greater than the job timeout specified in your GitLab Runner configuration, otherwise a runner may erroneously be considered stale.
+
+## Installation
+
+1. Download the appropriate binary from [tagged releases](https://git.ethitter.com/debian/gitlab-runner-do-monitor/tags), or build the binary yourself.
+1. Copy `config-sample.json` to an appropriate location and update the default values as needed.
+1. Create a cron task to periodically run the monitor.
+
+## Usage
+
+```bash
+./glrdomon -config config.json
+```
+
+* `-config`: specify path to config file, otherwise assumes `./config.json` relative to the binary

config-sample.json

+{
+  "log-dest": "os.Stdout",
+  "api-key": "",
+  "threshold": 3600,
+  "delete-stale": true
+}

glrdomon.go

 package main
 
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/digitalocean/godo"
+	"github.com/dustin/go-humanize"
+	"golang.org/x/oauth2"
+)
+
+type config struct {
+	LogDest     string `json:"log-dest"`
+	APIKey      string `json:"api-key"`
+	Threshold   int    `json:"threshold"`
+	DeleteStale bool   `json:"delete-stale"`
+}
+
+type tokenSource struct {
+	AccessToken string
+}
+
+var (
+	configPath string
+
+	logger  *log.Logger
+	logDest string
+
+	apiKey      string
+	threshold   int
+	deleteStale bool
+
+	wg sync.WaitGroup
+
+	client *godo.Client
+)
+
+func init() {
+	flag.StringVar(&configPath, "config", "./config.json", "Path to configuration file")
+	flag.Parse()
+
+	if !validatePath(&configPath) {
+		usage()
+	}
+
+	configFile, err := ioutil.ReadFile(configPath)
+	if err != nil {
+		usage()
+	}
+
+	cfg := config{}
+	if err = json.Unmarshal(configFile, &cfg); err != nil {
+		usage()
+	}
+
+	apiKey = cfg.APIKey
+	threshold = cfg.Threshold
+	deleteStale = cfg.DeleteStale
+
+	logDest = cfg.LogDest
+	setUpLogger()
+
+	logger.Printf("Starting GitLab Runner monitoring with config %s", configPath)
+
+	if deleteStale {
+		logger.Println("Stale droplets WILL BE DELETED automatically")
+	} else {
+		logger.Println("Stale droplets will be logged, but not deleted")
+	}
+}
+
 func main() {
+	authenticate()
+	checkAPI()
+
+	wg.Wait()
+	logger.Println("Execution complete!")
+}
+
+func authenticate() {
+	tokenSource := &tokenSource{
+		AccessToken: apiKey,
+	}
+
+	oauthClient := oauth2.NewClient(context.Background(), tokenSource)
+	client = godo.NewClient(oauthClient)
+}
+
+// oAuth token
+func (t *tokenSource) Token() (*oauth2.Token, error) {
+	token := &oauth2.Token{
+		AccessToken: t.AccessToken,
+	}
+
+	return token, nil
+}
+
+func checkAPI() {
+	ctx := context.TODO()
+	droplets, err := listDroplets(ctx, client)
+	if err != nil {
+		logger.Println("Warning! Failed to retrieve droplet list.")
+		logger.Print(err)
+		return
+	}
+
+	for _, droplet := range droplets {
+		wg.Add(1)
+		go checkDroplet(droplet)
+	}
+}
+
+func listDroplets(ctx context.Context, client *godo.Client) ([]godo.Droplet, error) {
+	list := []godo.Droplet{}
+
+	opt := &godo.ListOptions{}
+	for {
+		droplets, resp, err := client.Droplets.List(ctx, opt)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, d := range droplets {
+			list = append(list, d)
+		}
+
+		if resp.Links == nil || resp.Links.IsLastPage() {
+			break
+		}
+
+		page, err := resp.Links.CurrentPage()
+		if err != nil {
+			return nil, err
+		}
+
+		opt.Page = page + 1
+	}
+
+	return list, nil
+}
+
+func checkDroplet(droplet godo.Droplet) {
+	defer wg.Done()
+
+	if !checkDropletAge(droplet) {
+		return
+	}
+
+	deleted := deleteDroplet(droplet)
+	if deleteStale {
+		if deleted {
+			logger.Printf("Removed droplet %s (%d)", droplet.Name, droplet.ID)
+		} else {
+			logger.Printf("Failed to delete droplet %s (%d)", droplet.Name, droplet.ID)
+		}
+	}
+}
+
+func checkDropletAge(droplet godo.Droplet) bool {
+	thr := time.Now().Add(time.Duration(-threshold) * time.Second)
+	created, err := time.Parse(time.RFC3339, droplet.Created)
+	if err != nil {
+		logger.Printf("Could not parse created-timestamp for droplet ID %d", droplet.ID)
+		return false
+	}
+
+	stale := thr.After(created)
+
+	if stale {
+		logger.Printf("Stale droplet => ID: %d; name: \"%s\"; created: %s, %s (%d)", droplet.ID, droplet.Name, humanize.Time(created), droplet.Created, created.Unix())
+	}
+
+	return stale
+}
+
+func deleteDroplet(droplet godo.Droplet) bool {
+	if !deleteStale {
+		return false
+	}
+
+	logger.Printf("Deleting droplet %s (%d)", droplet.Name, droplet.ID)
+
+	ctx := context.TODO()
+	_, err := client.Droplets.Delete(ctx, droplet.ID)
+
+	return err == nil
+}
+
+func setUpLogger() {
+	logOpts := log.Ldate | log.Ltime | log.LUTC | log.Lshortfile
+
+	if logDest == "os.Stdout" {
+		logger = log.New(os.Stdout, "DEBUG: ", logOpts)
+	} else {
+		path, err := filepath.Abs(logDest)
+		if err != nil {
+			logger.Fatal(err)
+		}
+
+		logFile, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		logger = log.New(logFile, "", logOpts)
+	}
+}
+
+func validatePath(path *string) bool {
+	if len(*path) <= 1 {
+		return false
+	}
+
+	var err error
+	*path, err = filepath.Abs(*path)
+
+	if err != nil {
+		logger.Printf("Error: %s", err.Error())
+		return false
+	}
+
+	if _, err = os.Stat(*path); os.IsNotExist(err) {
+		return false
+	}
+
+	return true
+}
 
+func usage() {
+	flag.Usage()
+	os.Exit(3)
 }

glrdomon_test.go

 package main
 
-import "testing"
+import (
+	"testing"
+	"time"
+
+	"github.com/digitalocean/godo"
+)
+
+func TestCheckDropletAge(t *testing.T) {
+	staleDroplet := godo.Droplet{
+		ID:      1234,
+		Name:    "very-old",
+		Created: "2000-08-19T19:07:04Z",
+	}
+
+	if !checkDropletAge(staleDroplet) {
+		t.Error("Failed to assert that very old droplet is stale")
+	}
+
+	now := time.Now()
+	newDroplet := godo.Droplet{
+		ID:      5678,
+		Name:    "new",
+		Created: now.Format(time.RFC3339),
+	}
+
+	if checkDropletAge(newDroplet) {
+		t.Error("Asserted that brand-new droplet is stale")
+	}
+}
+
+func TestValidatePath(t *testing.T) {
+	emptyString := ""
+	notValid := validatePath(&emptyString)
+
+	if notValid == true {
+		t.Error("Empty path shouldn't validate")
+	}
+
+	sampleConfig := "./config-sample.json"
+	valid := validatePath(&sampleConfig)
+
+	if valid != true {
+		t.Error("Couldn't validate path to sample config")
+	}
+}