Use a more standardized project layout

In #2, mrngm made the point that we should move to a more
standardized project structure. This commit does exactly that.
The new project structure is based on the repository listed at
<https://github.com/golang-standards/project-layout>.

Fixes #2.

cmd/rushlink/main.go

@@ -8,7 +8,10 @@ import (
 
 	"github.com/gorilla/mux"
 	"github.com/pkg/errors"
-	bolt "go.etcd.io/bbolt"
+
+	"gitea.hashru.nl/dsprenkels/rushlink/internal/db"
+	"gitea.hashru.nl/dsprenkels/rushlink/internal/handlers"
+	"gitea.hashru.nl/dsprenkels/rushlink/internal/metrics"
 )
 
 type ParsedArguments struct {
@@ -16,7 +19,6 @@ type ParsedArguments struct {
 }
 
 var appConfig ParsedArguments
-var db *bolt.DB
 
 func main() {
 	// Parse the arguments and construct the ParsedArguments
@@ -26,29 +28,18 @@ func main() {
 	}
 	appConfig = *appConfigRef
 
-	// Open the bolt database
+	db.Init(appConfig.databaseName)
-	db, err = bolt.Open(appConfig.databaseName, 0666, &bolt.Options{Timeout: 1 * time.Second})
-	if err != nil {
-		decoratedErr := errors.Wrapf(err, "failed to open database at '%v'", appConfig.databaseName)
-		log.Fatal(decoratedErr)
-	}
-	defer db.Close()
-	err = db.Update(migrateDatabase)
-	if err != nil {
-		decoratedErr := errors.Wrapf(err, "failed to migrate database")
-		log.Fatal(decoratedErr)
-	}
 
 	// Export prometheus metrics
-	go startMetricsServer()
+	go metrics.StartMetricsServer()
 
 	// Initialize Gorilla router
 	router := mux.NewRouter()
-	router.HandleFunc("/", indexGetHandler).Methods("GET")
+	router.HandleFunc("/", handlers.IndexGetHandler).Methods("GET")
-	router.HandleFunc("/", indexPostHandler).Methods("POST")
+	router.HandleFunc("/", handlers.IndexPostHandler).Methods("POST")
-	router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}", pasteGetHandler).Methods("GET")
+	router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}", handlers.PasteGetHandler).Methods("GET")
-	router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}/nr", pasteGetHandlerNoRedirect).Methods("GET")
+	router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}/nr", handlers.PasteGetHandlerNoRedirect).Methods("GET")
-	router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}/meta", pasteGetHandlerMeta).Methods("GET")
+	router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}/meta", handlers.PasteGetHandlerMeta).Methods("GET")
 
 	// Start the server
 	srv := &http.Server{

cmd/rushlink/metrics.go

@@ -1,54 +0,0 @@
-package main
-
-import (
-	"log"
-	"net/http"
-	"time"
-
-	bolt "go.etcd.io/bbolt"
-
-	"github.com/gorilla/mux"
-	"github.com/pkg/errors"
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/promauto"
-	"github.com/prometheus/client_golang/prometheus/promhttp"
-)
-
-const (
-	METRICS_ADDR = "127.0.0.1:58614"
-)
-
-var (
-	shortenUrlsTotal = promauto.NewGaugeFunc(prometheus.GaugeOpts{
-		Namespace: "rushlink",
-		Subsystem: "shorten",
-		Name:      "urls_total",
-		Help:      "The current amount of shortened urls in the database.",
-	}, func() float64 {
-		var metric float64
-		if err := db.View(func(tx *bolt.Tx) error {
-			bucket := tx.Bucket([]byte("shorten"))
-			if bucket == nil {
-				return errors.New("bucket 'shorten' could not be found")
-			}
-			metric = float64(bucket.Stats().KeyN)
-			return nil
-		}); err != nil {
-			log.Printf("error: %v", errors.Wrap(err, "fetching shorten_urls_total metric"))
-			return 0
-		}
-		return metric
-	})
-)
-
-func startMetricsServer() {
-	router := mux.NewRouter()
-	router.Handle("/metrics", promhttp.Handler()).Methods("GET")
-	srv := &http.Server{
-		Handler:      router,
-		Addr:         METRICS_ADDR,
-		WriteTimeout: 15 * time.Second,
-		ReadTimeout:  15 * time.Second,
-	}
-	log.Fatal(srv.ListenAndServe())
-}

go.mod

@@ -3,6 +3,7 @@ module gitea.hashru.nl/dsprenkels/rushlink
 go 1.12
 
 require (
+	github.com/go-bindata/go-bindata v3.1.2+incompatible // indirect
 	github.com/gorilla/mux v1.7.3
 	github.com/pkg/errors v0.8.1
 	github.com/prometheus/client_golang v1.1.0

go.sum

@@ -6,6 +6,7 @@ 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/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-bindata/go-bindata v3.1.2+incompatible/go.mod h1:xK8Dsgwmeed+BBsSy2XTopBn/8uK2HWuGSnA11C3Joo=
 github.com/go-kit/kit v0.8.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
 github.com/go-logfmt/logfmt v0.3.0/go.mod h1:Qt1PoO58o5twSAckw1HlFXLmHsOX5/0LbT9GBnD5lWE=
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=

internal/db/db.go

@@ -1,13 +1,18 @@
-package main
+package db
 
 import (
 	"fmt"
 	"log"
+	"time"
 
-	"gitea.hashru.nl/dsprenkels/rushlink/gobmarsh"
+	"github.com/pkg/errors"
 	bolt "go.etcd.io/bbolt"
+
+	"gitea.hashru.nl/dsprenkels/rushlink/pkg/gobmarsh"
 )
 
+var DB *bolt.DB
+
 // The current database version
 //
 // If we alter the database format, we bump this number and write a new
@@ -25,6 +30,16 @@ const BUCKET_PASTES = "pastes"
 // CURRENT_MIGRATE_VERSION, the database has to be migrated.
 const KEY_MIGRATE_VERSION = "migrate_version"
 
+// Open the bolt database
+func Init(name string) error {
+	var err error
+	DB, err = bolt.Open(name, 0666, &bolt.Options{Timeout: 1 * time.Second})
+	if err != nil {
+		return errors.Wrapf(err, "failed to open database at '%v'", name)
+	}
+	return DB.Update(migrateDatabase)
+}
+
 // Initialize and migrate the database to the current version
 func migrateDatabase(tx *bolt.Tx) error {
 	dbVersion, err := dbVersion(tx)

internal/handlers/handlers.go

@@ -1,8 +1,8 @@
-package main
+package handlers
 
 //go:generate go get github.com/go-bindata/go-bindata
 //go:generate go get -u github.com/go-bindata/go-bindata/...
-//go:generate go-bindata -pkg $GOPACKAGE text/
+//go:generate go-bindata -pkg $GOPACKAGE -prefix ../../assets ../../assets/...
 
 import (
 	"bytes"
@@ -19,10 +19,12 @@ import (
 	"time"
 	"unicode"
 
-	"gitea.hashru.nl/dsprenkels/rushlink/gobmarsh"
 	"github.com/gorilla/mux"
 	"github.com/pkg/errors"
 	bolt "go.etcd.io/bbolt"
+
+	"gitea.hashru.nl/dsprenkels/rushlink/internal/db"
+	"gitea.hashru.nl/dsprenkels/rushlink/pkg/gobmarsh"
 )
 
 type PasteType int
@@ -82,13 +84,13 @@ func (t PasteState) String() (string, error) {
 	}
 }
 
-func indexGetHandler(w http.ResponseWriter, r *http.Request) {
+func IndexGetHandler(w http.ResponseWriter, r *http.Request) {
 	if err := indexTemplate.Execute(w, nil); err != nil {
 		panic(err)
 	}
 }
 
-func indexPostHandler(w http.ResponseWriter, r *http.Request) {
+func IndexPostHandler(w http.ResponseWriter, r *http.Request) {
 	if err := r.ParseMultipartForm(50 * 1000 * 1000); err != nil {
 		w.WriteHeader(http.StatusInternalServerError)
 		fmt.Fprintf(w, "Internal server error: %v\n", err)
@@ -115,18 +117,18 @@ func indexPostHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	shortenPostHandler(w, r)
+	ShortenPostHandler(w, r)
 }
 
-func pasteGetHandler(w http.ResponseWriter, r *http.Request) {
+func PasteGetHandler(w http.ResponseWriter, r *http.Request) {
 	pasteGetHandlerInner(w, r, false, false)
 }
 
-func pasteGetHandlerNoRedirect(w http.ResponseWriter, r *http.Request) {
+func PasteGetHandlerNoRedirect(w http.ResponseWriter, r *http.Request) {
 	pasteGetHandlerInner(w, r, true, false)
 }
 
-func pasteGetHandlerMeta(w http.ResponseWriter, r *http.Request) {
+func PasteGetHandlerMeta(w http.ResponseWriter, r *http.Request) {
 	pasteGetHandlerInner(w, r, false, true)
 }
 
@@ -134,7 +136,7 @@ func pasteGetHandlerInner(w http.ResponseWriter, r *http.Request, noRedirect, sh
 	vars := mux.Vars(r)
 	key := vars["key"]
 	var storedPaste *StoredPaste
-	if err := db.View(func(tx *bolt.Tx) error {
+	if err := db.DB.View(func(tx *bolt.Tx) error {
 		var err error
 		storedPaste, err = getURL(tx, []byte(key))
 		return err
@@ -204,7 +206,7 @@ func pasteGetHandlerInner(w http.ResponseWriter, r *http.Request, noRedirect, sh
 	}
 }
 
-func shortenPostHandler(w http.ResponseWriter, r *http.Request) {
+func ShortenPostHandler(w http.ResponseWriter, r *http.Request) {
 	rawurl := r.PostForm.Get("shorten")
 	userURL, err := url.ParseRequestURI(rawurl)
 	if err != nil {
@@ -224,7 +226,7 @@ func shortenPostHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	var storedPaste *StoredPaste
-	if err := db.Update(func(tx *bolt.Tx) error {
+	if err := db.DB.Update(func(tx *bolt.Tx) error {
 		ownerKey, ok := getOwnerTokenFromRequest(r)
 		if ok == false {
 			// Owner key not supplied or invalid, generate a new one
@@ -262,9 +264,9 @@ func shortenPostHandler(w http.ResponseWriter, r *http.Request) {
 
 // Retrieve a URL from the database
 func getURL(tx *bolt.Tx, key []byte) (*StoredPaste, error) {
-	shortenBucket := tx.Bucket([]byte(BUCKET_PASTES))
+	shortenBucket := tx.Bucket([]byte(db.BUCKET_PASTES))
 	if shortenBucket == nil {
-		return nil, fmt.Errorf("bucket %v does not exist", BUCKET_PASTES)
+		return nil, fmt.Errorf("bucket %v does not exist", db.BUCKET_PASTES)
 	}
 	storedBytes := shortenBucket.Get(key)
 	if storedBytes == nil {
@@ -279,9 +281,9 @@ func getURL(tx *bolt.Tx, key []byte) (*StoredPaste, error) {
 //
 // Returns the new ID if the url was successfully shortened
 func shortenURL(tx *bolt.Tx, userURL *url.URL, ownerKey [16]byte) (*StoredPaste, error) {
-	shortenBucket := tx.Bucket([]byte(BUCKET_PASTES))
+	shortenBucket := tx.Bucket([]byte(db.BUCKET_PASTES))
 	if shortenBucket == nil {
-		return nil, fmt.Errorf("bucket %v does not exist", BUCKET_PASTES)
+		return nil, fmt.Errorf("bucket %v does not exist", db.BUCKET_PASTES)
 	}
 
 	// Generate a key until it is not in the database, this occurs in O(log N),

internal/metrics/metrics.go

@@ -0,0 +1,55 @@
+package metrics
+
+import (
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/gorilla/mux"
+	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	bolt "go.etcd.io/bbolt"
+
+	"gitea.hashru.nl/dsprenkels/rushlink/internal/db"
+)
+
+const (
+	METRICS_ADDR = "127.0.0.1:58614"
+)
+
+func StartMetricsServer() {
+	var (
+		_ = promauto.NewGaugeFunc(prometheus.GaugeOpts{
+			Namespace: "rushlink",
+			Subsystem: "shorten",
+			Name:      "urls_total",
+			Help:      "The current amount of shortened urls in the database.",
+		}, func() float64 {
+			var metric float64
+			if err := db.DB.View(func(tx *bolt.Tx) error {
+				bucket := tx.Bucket([]byte("shorten"))
+				if bucket == nil {
+					return errors.New("bucket 'shorten' could not be found")
+				}
+				metric = float64(bucket.Stats().KeyN)
+				return nil
+			}); err != nil {
+				log.Printf("error: %v", errors.Wrap(err, "fetching shorten_urls_total metric"))
+				return 0
+			}
+			return metric
+		})
+	)
+
+	router := mux.NewRouter()
+	router.Handle("/metrics", promhttp.Handler()).Methods("GET")
+	srv := &http.Server{
+		Handler:      router,
+		Addr:         METRICS_ADDR,
+		WriteTimeout: 15 * time.Second,
+		ReadTimeout:  15 * time.Second,
+	}
+	log.Fatal(srv.ListenAndServe())
+}