Implemented better output management

Previously we were piping the output to `~/.ssh/authorized_keys`
but that's not good because if there happen an error, we mess up
our authorized_keys file.
Now we update target file only if we manage to fetch the keys.

README.md

@@ -5,24 +5,24 @@
 
 ## Usage
 ```shell
-fetch-ssh-keys <source name> <parameters>
+fetch-ssh-keys <source name> <parameters> <output file>
 ```
 
 For example fetch users public SSH keys from GitHub `my-lovely-team` team in `my-awesome-company` organization and output in SSH authorized_keys format
 ```shell
-fetch-ssh-keys github --organization my-awesome-company --team my-lovely-team --token YOUR-TOKEN-HERE
+fetch-ssh-keys github --organization my-awesome-company --team my-lovely-team --token YOUR-TOKEN-HERE ./the-keys
 ```
 
-Tool can be used for example to automatically update `.ssh/authorized_keys` file by adding the script to cron job.
+Tool can be used for example to automatically update `.ssh/authorized_keys` file by giving path to `.ssh/authorized_keys` as last argument and adding the script to cron job.
 
 ## Installation
 - Download binary from [releases](https://github.com/ernoaapa/fetch-ssh-keys/releases)
 - Give execution rights (`chmod +x fetch-ssh-keys`) and add it into your $PATH
 
 ### Configuration
-| Parameter      | Required | Description                                                                                               |
-|----------------|----------|-----------------------------------------------------------------------------------------------------------|
-| --output       | Yes      | Output format. Only ssh authorized_keys format supported for now                                          |
+| Parameter      | Required          | Description                                                                                               |
+|----------------|-------------------|-----------------------------------------------------------------------------------------------------------|
+| --format       | No (default ssh)  | Output format. Only ssh authorized_keys format supported for now                                          |
 
 #### GitHub
 | Parameter      | Required | Description                                                                                               |
@@ -38,7 +38,7 @@ Tool can be used for example to automatically update `.ssh/authorized_keys` file
 go get ./...
 ```
 
-### Run stastd-exec
+### Run
 ```shell
 go run main.go github --output ssh
 ```

format/builder.go

@@ -0,0 +1,13 @@
+package format
+
+import log "github.com/Sirupsen/logrus"
+
+// Build builds output in given formatName format
+func Build(formatName string, keysByUsername map[string][]string) string {
+	switch formatName {
+	case "ssh":
+		return ssh(keysByUsername)
+	}
+	log.Fatalf("Invalid output format name: %s", formatName)
+	return ""
+}

output/ssh.go → format/ssh.go

@@ -1,4 +1,4 @@
-package output
+package format
 
 import (
 	"bytes"

output/ssh_test.go → format/ssh_test.go

@@ -1,4 +1,4 @@
-package output
+package format
 
 import (
 	"testing"

main.go

@@ -24,7 +24,7 @@ func main() {
 	app.Usage = "Fetch user public SSH keys"
 	app.Flags = []cli.Flag{
 		cli.StringFlag{
-			Name:  "output, o",
+			Name:  "format, f",
 			Usage: "Output format. One of: ssh",
 			Value: "ssh",
 		},
@@ -67,8 +67,7 @@ func main() {
 					log.Fatalln("Failed to fetch keys", err)
 				}
 
-				println(output.Build(c.GlobalString("output"), keys))
-				return nil
+				return output.Write(c.GlobalString("format"), c.Args().Get(0), keys)
 			},
 		},
 	}

output/file.go

@@ -0,0 +1,24 @@
+package output
+
+import (
+	"io/ioutil"
+	"os"
+)
+
+// FileWriter writes the output to file
+type FileWriter struct {
+	targetFile string
+	fileMode   os.FileMode
+}
+
+// NewFileWriter creates new FileWriter what writes to targetFile
+func NewFileWriter(targetFile string) *FileWriter {
+	return &FileWriter{
+		targetFile: targetFile,
+		fileMode:   0600,
+	}
+}
+
+func (w *FileWriter) write(output string) error {
+	return ioutil.WriteFile(w.targetFile, []byte(output), w.fileMode)
+}

output/file_test.go

@@ -0,0 +1,27 @@
+package output
+
+import (
+	"io/ioutil"
+	"testing"
+
+	log "github.com/Sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFile(t *testing.T) {
+	log.SetLevel(log.DebugLevel)
+	log.Println("hwllllwe")
+
+	file, createErr := ioutil.TempFile("", "example")
+	assert.NoError(t, createErr, "Unable to create temp file")
+
+	writer := NewFileWriter(file.Name())
+
+	writer.write("foobar")
+	writer.write("foobar-second-time")
+
+	fileBytes, readErr := ioutil.ReadFile(file.Name())
+	assert.NoError(t, readErr, "Unable to read temp file")
+
+	assert.Equal(t, "foobar-second-time", string(fileBytes), "FileWriter didnt wrote expected output to file")
+}

output/stdout.go

@@ -0,0 +1,11 @@
+package output
+
+import "fmt"
+
+// StdoutWriter just writes the output to stdout
+type StdoutWriter struct{}
+
+func (w *StdoutWriter) write(output string) error {
+	fmt.Println(output)
+	return nil
+}

output/stdout_test.go

@@ -0,0 +1,14 @@
+package output
+
+import (
+	"testing"
+
+	log "github.com/Sirupsen/logrus"
+)
+
+func TestStdout(t *testing.T) {
+	log.SetLevel(log.DebugLevel)
+
+	writer := &StdoutWriter{}
+	writer.write("whoop")
+}

output/writer.go

@@ -0,0 +1,23 @@
+package output
+
+import "github.com/ernoaapa/fetch-ssh-keys/format"
+
+// Writer is interface for all output writers
+type Writer interface {
+	write(output string) error
+}
+
+// Write writes keys to given outputName in given formatName
+func Write(formatName, target string, keysByUsername map[string][]string) error {
+	writer := getWriter(target)
+	return writer.write(format.Build(formatName, keysByUsername))
+}
+
+func getWriter(target string) Writer {
+	switch target {
+	case "":
+		return &StdoutWriter{}
+	default:
+		return NewFileWriter(target)
+	}
+}