Merge pull request #25 from abegaj/feat/otpauth-docker-file

Docker support

Dockerfile

@@ -0,0 +1,14 @@
+# Build
+FROM golang:1.18 AS builder
+
+COPY . /otpauth
+WORKDIR /otpauth
+
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o build/otpauth
+
+# Run
+FROM scratch
+
+COPY --from=builder /otpauth/build/otpauth /app/otpauth
+
+ENTRYPOINT ["/app/otpauth"]

README.md

@@ -15,12 +15,12 @@ to plain [otpauth links](https://github.com/google/google-authenticator/wiki/Key
 ### Flags
 
 ```
-  -cache string
-    	cache file (default "migration.bin")
+  -workdir string
+    	working directory to store eventual files (defaults to current one)
   -eval
     	evaluate otps
   -http string
-    	serve http (e.g. localhost:6060)
+    	serve http (e.g. :6060)
   -info
     	display batch info
   -link string
@@ -63,3 +63,26 @@ Will generate:
 ```
 
 Navigate to http://localhost:6060/
+
+## Docker
+A Docker container can also be used to run the application by building and running the image as following
+
+#### Build image
+From the current directory run
+```
+docker build . -t otpauth:latest
+```
+
+#### Run container
+To start a container from the previously created image run
+```
+docker run --name otpauth -p 6060:6060 -v $(pwd)/workdir:/app/workdir --rm otpauth:latest -workdir /app/workdir -http :6060 -link "otpauth-migration://offline?data=CjEKCkhlbGxvId6tvu8SGEV4YW1wbGU6YWxpY2VAZ29vZ2xlLmNvbRoHRXhhbXBsZTAC"
+```
+```
+-p 6060:6060
+Map the host 6060 to the containr 6060
+
+-v $(pwd)/workdir:/app/workdir
+Map the host dir to the containr dir
+```
+Navigate to http://localhost:6060/

main.go

@@ -8,10 +8,16 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"path/filepath"
 
 	"github.com/dim13/otpauth/migration"
 )
 
+const (
+	cacheFilename = "migration.bin"
+	revFile       = "otpauth-migration.png"
+)
+
 func migrationData(fname, link string) ([]byte, error) {
 	if link == "" {
 		// read from cache
@@ -27,17 +33,24 @@ func migrationData(fname, link string) ([]byte, error) {
 
 func main() {
 	var (
-		link  = flag.String("link", "", "migration link (required)")
-		cache = flag.String("cache", "migration.bin", "cache file")
-		http  = flag.String("http", "", "serve http (e.g. localhost:6060)")
-		eval  = flag.Bool("eval", false, "evaluate otps")
-		qr    = flag.Bool("qr", false, "generate QR-codes (optauth://)")
-		rev   = flag.Bool("rev", false, "reverse QR-code (otpauth-migration://)")
-		info  = flag.Bool("info", false, "display batch info")
+		link    = flag.String("link", "", "migration link (required)")
+		workdir = flag.String("workdir", "", "working directory")
+		http    = flag.String("http", "", "serve http (e.g. localhost:6060)")
+		eval    = flag.Bool("eval", false, "evaluate otps")
+		qr      = flag.Bool("qr", false, "generate QR-codes (optauth://)")
+		rev     = flag.Bool("rev", false, "reverse QR-code (otpauth-migration://)")
+		info    = flag.Bool("info", false, "display batch info")
 	)
 	flag.Parse()
 
-	data, err := migrationData(*cache, *link)
+	if *workdir != "" {
+		if err := os.MkdirAll(*workdir, 0700); err != nil {
+			log.Fatal("error creating working directory: ", err)
+		}
+	}
+
+	cacheFile := filepath.Join(*workdir, cacheFilename)
+	data, err := migrationData(cacheFile, *link)
 	if err != nil {
 		log.Fatal("-link parameter or cache file missing: ", err)
 	}
@@ -54,12 +67,15 @@ func main() {
 		}
 	case *qr:
 		for _, op := range p.OtpParameters {
-			if err := migration.PNG(op.FileName()+".png", op.URL()); err != nil {
+			fileName := op.FileName() + ".png"
+			qrFile := filepath.Join(*workdir, fileName)
+			if err := migration.PNG(qrFile, op.URL()); err != nil {
 				log.Fatal("write file: ", err)
 			}
 		}
 	case *rev:
-		if err := migration.PNG("otpauth-migration.png", migration.URL(data)); err != nil {
+		revFile := filepath.Join(*workdir, revFile)
+		if err := migration.PNG(revFile, migration.URL(data)); err != nil {
 			log.Fatal(err)
 		}
 	case *eval: