Cleanup of auth command

main.go

@@ -1,48 +1,102 @@
 package main
 
 import (
+	"bufio"
+	"bytes"
 	"flag"
 	"fmt"
+	"io"
+	"log"
+	"os"
+	"strings"
 
 	"github.com/awslabs/aws-sdk-go/aws"
-	"github.com/awslabs/aws-sdk-go/aws/awsutil"
 	"github.com/awslabs/aws-sdk-go/service/s3"
 )
 
 const (
+	// flagFileName is the configuration file used for sshauth
 	flagFileName = "/etc/sshauth/sshauth.conf"
-	debug        = "false"
+
+	// debug ("true"/"false") controls debug output
+	debug = "false"
+)
+
+var (
+	// name of s3 bucket
+	bucket = flag.String("bucket", "", "S3 Bucket name")
+
+	// name of s3 key prefix
+	key = flag.String("key", "", "S3 bucket key")
+
+	// username to authenticate
+	user = ""
+
+	svc = s3.New(nil)
+
+	usage = `Usage: sshauth [options] username
+
+Options:
+ -bucket             S3 bucket name
+ -key                S3 key prefix in bucket
+
+The final S3 url will be: bucket/prefix/username
+`
 )
 
+func init() {
+	flag.Usage = func() {
+		fmt.Fprint(os.Stderr, usage)
+	}
+}
+
 func main() {
+	readDefaultFlagFile()
 	flag.Parse()
 
-	listObjects(*bucket, *key)
-}
+	if *bucket == "" {
+		fmt.Println("S3 bucket is required.")
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	if flag.NArg() != 1 {
+		fmt.Println("Username is required")
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	user = flag.Arg(0)
 
-func getObject(bucket, key string) {
-	svc := s3.New(nil)
+	printAuthorizedKeys(*bucket, *key, user)
+}
 
+// readAuthorizedKey reads the authorized keys from S3
+func readAuthorizedKey(bucket, key string, r chan io.Reader) {
 	params := &s3.GetObjectInput{
 		Bucket: aws.String(bucket),
 		Key:    aws.String(key),
 	}
 	resp, err := svc.GetObject(params)
 
 	if awserr := aws.Error(err); awserr != nil {
-		// A service error occurred.
-		fmt.Println("Error:", awserr.Code, awserr.Message)
+		r <- bytes.NewReader([]byte(""))
+		printDbg("AWS Error(1):", awserr.Code, awserr.Message)
+		return
 	} else if err != nil {
-		// A non-service error occurred.
-		panic(err)
+		r <- bytes.NewReader([]byte(""))
+		printDbg("Error:", err)
 	}
 
-	// Pretty-print the response data.
-	fmt.Println(awsutil.StringValue(resp))
+	r <- resp.Body
 }
 
-func listObjects(bucket, key string) {
-	svc := s3.New(nil)
+// printAuthorizedKeys for specified bucket, prefix (key) and user
+// the used path will be bucket/prefix/user/*
+func printAuthorizedKeys(bucket, key, user string) {
+	keys := make(chan io.Reader, 5)
+
+	key = strings.TrimSuffix(key, "/") + "/" + user
 
 	params := &s3.ListObjectsInput{
 		Bucket: aws.String(bucket), // Required
@@ -51,17 +105,62 @@ func listObjects(bucket, key string) {
 	resp, err := svc.ListObjects(params)
 
 	if awserr := aws.Error(err); awserr != nil {
-		// A service error occurred.
-		fmt.Println("Error:", awserr.Code, awserr.Message)
+		log.Fatal("AWS Error(2):", awserr.Code, awserr.Message)
 	} else if err != nil {
-		// A non-service error occurred.
-		panic(err)
+		log.Fatal("Error:", err)
+	}
+
+	for _, content := range resp.Contents {
+		go readAuthorizedKey(bucket, *content.Key, keys)
+	}
+
+	for range resp.Contents {
+		_, err = io.Copy(os.Stdout, <-keys)
+		if err != nil {
+			log.Println("Unable to copy to stdout:", err)
+		}
+	}
+}
+
+// readDefaultFlagFile reads the default flag file, see readFlagFile
+func readDefaultFlagFile() {
+	readFlagFile(flagFileName)
+}
+
+// readFlagFile will read a file containing command line flags.
+// These flags will be added before flags on the command line, therfore
+// those flags will override. Note, if flags are read into an array they
+// will not be overridden, but appended.
+func readFlagFile(flagFileName string) {
+	flagFile, err := os.Open(flagFileName)
+	if err != nil {
+		dir, _ := os.Getwd()
+		printDbg("Unable to open file: ", flagFileName, ", In folder:", dir)
+		return
+	}
+	defer flagFile.Close()
+
+	printDbg("Reading flag file:", flagFileName)
+
+	var newArgs []string
+	newArgs = append(newArgs, os.Args[0])
+
+	// Read arguments from file
+	scanner := bufio.NewScanner(flagFile)
+	scanner.Split(bufio.ScanWords)
+	for scanner.Scan() {
+		newArgs = append(newArgs, scanner.Text())
+	}
+
+	// Add arguments from command line after
+	for i := 1; i < len(os.Args); i++ {
+		newArgs = append(newArgs, os.Args[i])
 	}
 
-	// Pretty-print the response data.
-	fmt.Println(awsutil.StringValue(resp))
+	os.Args = newArgs
 }
 
+// printDbg prints debug messages
 func printDbg(s ...interface{}) {
 	if debug == "true" {
 		fmt.Print(" * ")