Merge pull request #3 from andygeorge/andygeorge/injection-go

Rewrite in Golang

.gitignore

@@ -1,2 +1,3 @@
 example_files/
 output/
+/go/build/*

README.md

@@ -21,42 +21,26 @@ Or, manually:
 
 ## Example
 
-- Create a Butane config file, `hello_world.bu`:
-
-```yaml
-variant: fcos
-version: 1.4.0
-
-storage:
-  directories:
-    - path: /tmp/example
-      mode: 0755
-
-  files:
-    - path: /tmp/example/hello_world.txt
-      mode: 0755
-      contents:
-        inline: |
-          Hello, world!
+- Use the example Butane config file:
+```shell
+cp example_butane.bu example_files/example.bu
 ```
 
+- The file `example_files/example.bu` should be populated
+
 - Create an Ignition config using Butane:
+```shell
+butane --strict example_files/example.bu > example_files/example.ign
+```
 
-```bash
-$ butane --strict hello_world.bu > hello_world.ign
-$ cat hello_world.ign
-{"ignition":{"version":"3.3.0"},"storage":{"directories":[{"path":"/tmp/example","mode":493}],"files":[{"path":"/tmp/example/hello_world.txt","contents":{"compression":"","source":"data:,Hello%2C%20world!%0A"},"mode":493}]}}
+- The file `example_files/example.ign` should be populated and look like this:
+```json
+{"ignition":{"version":"3.3.0"},"storage":{"directories":[{"path":"/tmp/example","mode":493}],"files":[{"path":"/tmp/example/hello_world.txt","contents":{"compression":"","source":"data:,Hello%2C%20world!%0A"},"mode":420},{"path":"/tmp/example/hello_world_gzip.txt","contents":{"compression":"gzip","source":"data:;base64,H4sIAAAAAAAC/zSQQc4UOwyE9+8UdYBRn+IhgcQSxNoknu6Skjjj2MOI06MwP7soicv1fd8uLnBB0LNcaOKnOj5ra4Yf5q3izqaISwK/2BpyKc7fnCjWp+tatAEOxKX4cg4GbRz4aq4dnCs7qjVzLAaka9xQbCwtoZEOqZxcLBwntDFuWFpRDcpc3SpC+zQHR2FlzRHIQJOf5gqNd7aiyzkE0vhIOfA9oIMdUtG5D08dlH7DI7kwbIVnhb7UC0N2YWRr0ou9k/cnLu5NfyM5oS+obORu1d4Ej5Q48P+OlAwFPV0/YDngOl0vHVWdsS+e1nKGhOK5SaFrKQpb+6dIoYl7npTA2IUwxSmRfuDTq+gMze1xBKwU0SKBkpNVYk/YwHRj1bEtblMcKNmmbG7Y/c5CQdWlvl+7tV1DtiBW6Prwmv34708AAAD//9sohz4WAgAA"},"mode":420}]},"systemd":{"units":[{"contents":"[Unit]\nDescription=Hello world service\n\n[Service]\nType=oneshot\nExecStart=/usr/bin/echo \"hello world\"\nStandardOutput=journal\n\n[Install]\nWantedBy=multi-user.target default.target\n","enabled":true,"name":"hello-world.service"}]}}
 ```
 
 - Run Injection:
-
-```bash
-$ sudo injection hello_world.ign
-Creating directory: /tmp/example
-Creating file: /tmp/example/hello_world.txt
-
-$ cat /tmp/example/hello_world.txt
-Hello, world!
+```shell
+# TODO: injection example
 ```
 
 ## Ignition support

example_butane.bu

@@ -0,0 +1,47 @@
+variant: fcos
+version: 1.4.0
+
+storage:
+  directories:
+    - path: /tmp/example
+      mode: 0755
+
+    - path: /tmp/example2
+
+    - path: /tmp/example3/example4
+      mode: 0744
+
+  files:
+    - path: /tmp/example/hello_world.txt
+      contents:
+        inline: |
+          Hello, world!
+
+    - path: /tmp/example/hello_world_gzip.txt
+      mode: 0644
+      contents:
+        inline: |
+          This is a much larger Hello World file that will use gzip compression
+          in the Ignition. Lorem ipsum dolor sit amet, consectetur adipisicing
+          elit, sed do eiusmod tempor incididunt ut labore et dolore magna
+          aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco
+          laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor
+          in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla
+          pariatur. Excepteur sint occaecat cupidatat non proident, sunt in
+          culpa qui officia deserunt mollit anim id est laborum.
+
+systemd:
+  units:
+    - name: hello-world.service
+      enabled: true
+      contents: |
+        [Unit]
+        Description=Hello world service
+
+        [Service]
+        Type=oneshot
+        ExecStart=/usr/bin/echo "hello world"
+        StandardOutput=journal
+
+        [Install]
+        WantedBy=multi-user.target default.target

go/README.md

@@ -0,0 +1,13 @@
+# injection-go
+`injection` built in Go.
+
+```shell
+# generate ignition
+butane --strict ../example_files/example.bu > ../example_files/example.ign
+
+# build injection
+go mod tidy && go fmt *.go && go build -o build/
+
+# run injection
+./build/injection ../example_files/example.ign
+```

go/go.mod

@@ -0,0 +1,3 @@
+module injection
+
+go 1.19

go/injection.go

@@ -0,0 +1,200 @@
+package main
+
+import (
+	"compress/gzip"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/url"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+const (
+	DefaultDirectoryMode       os.FileMode = 0755
+	DefaultFileMode            os.FileMode = 0644
+	DefaultSystemdUnitFileMode os.FileMode = 0644
+	DefaultSystemdUnitPath     string      = "/etc/systemd/system"
+)
+
+type IgnitionConfig struct {
+	Storage struct {
+		Directories []struct {
+			Path string `json:"path"`
+			Mode int    `json:"mode"`
+		} `json:"directories"`
+		Files []struct {
+			Path     string `json:"path"`
+			Mode     int    `json:"mode"`
+			Contents struct {
+				Compression string `json:"compression"`
+				Source      string `json:"source"`
+			} `json:"contents"`
+		} `json:"files"`
+	} `json:"storage"`
+	Systemd struct {
+		Units []struct {
+			Name     string `json:"name"`
+			Enabled  bool   `json:"enabled"`
+			Contents string `json:"contents"`
+		} `json:"units"`
+	} `json:"systemd"`
+}
+
+func main() {
+	var filename string
+	var ignitionConfig IgnitionConfig
+	var err error
+
+	args := os.Args[1:]
+
+	if len(args) < 1 {
+		fmt.Println("Specify a filename!")
+		os.Exit(1)
+	} else {
+		filename = args[0]
+	}
+
+	readFile, err := os.ReadFile(filename)
+	check(err)
+
+	err = json.Unmarshal([]byte(string(readFile)), &ignitionConfig)
+	check(err)
+
+	err = WriteDirectories(ignitionConfig)
+	check(err)
+
+	err = WriteFiles(ignitionConfig)
+	check(err)
+
+	err = WriteUnits(ignitionConfig)
+	check(err)
+}
+
+func OpenFile(path string, mode os.FileMode) (*os.File, error) {
+	options := os.O_WRONLY | os.O_TRUNC | os.O_CREATE
+
+	return os.OpenFile(path, options, mode)
+}
+
+func WriteDirectories(ignitionConfig IgnitionConfig) error {
+	var err error
+
+	for _, directoryConfig := range ignitionConfig.Storage.Directories {
+		path := directoryConfig.Path
+		mode := DefaultDirectoryMode
+		fmt.Println(path)
+
+		if directoryConfig.Mode != 0 {
+			mode = os.FileMode(directoryConfig.Mode)
+		}
+
+		if _, err = os.Stat(path); os.IsNotExist(err) {
+			err = os.MkdirAll(path, mode)
+		} else {
+			err = os.Chmod(path, mode)
+		}
+	}
+
+	return err
+}
+
+func WriteFiles(ignitionConfig IgnitionConfig) error {
+	var err error
+	var targetFile *os.File
+
+	for _, fileConfig := range ignitionConfig.Storage.Files {
+		path := fileConfig.Path
+		mode := DefaultFileMode
+		compression := fileConfig.Contents.Compression
+		source := fileConfig.Contents.Source
+		var rawData, unescapedData string
+		var decodedGzipData []byte
+		fmt.Println(path)
+
+		if fileConfig.Mode != 0 {
+			mode = os.FileMode(fileConfig.Mode)
+		}
+
+		if compression == "gzip" {
+			idx := strings.Index(source, ";base64,")
+			rawData = source[idx+8:]
+
+			gz, err := decodeBase64Data(rawData)
+			decodedGzipData, err = decodeGzipData(string(gz))
+			targetFile, err = OpenFile(path, mode)
+			if err != nil {
+				return err
+			}
+			defer targetFile.Close()
+			fmt.Fprintf(targetFile, "%s", string(decodedGzipData))
+		} else {
+			idx := strings.Index(source, ",")
+			rawData = source[idx+1:]
+
+			targetFile, err = OpenFile(path, mode)
+			if err != nil {
+				return err
+			}
+			defer targetFile.Close()
+			unescapedData, err = url.QueryUnescape(rawData)
+			fmt.Fprintf(targetFile, "%s", unescapedData)
+		}
+	}
+
+	return err
+}
+
+func WriteUnits(ignitionConfig IgnitionConfig) error {
+	var err error
+	var targetFile *os.File
+
+	for _, unitConfig := range ignitionConfig.Systemd.Units {
+		path := DefaultSystemdUnitPath + "/" + unitConfig.Name
+		mode := DefaultSystemdUnitFileMode
+		fmt.Println(path)
+
+		unitEnabledString := "disable"
+		if unitConfig.Enabled {
+			unitEnabledString = "enable"
+		}
+
+		targetFile, err = OpenFile(path, mode)
+		fmt.Fprintf(targetFile, "%s", unitConfig.Contents)
+		defer targetFile.Close()
+		check(err)
+
+		cmd := exec.Command("systemctl", unitEnabledString, unitConfig.Name)
+		err = cmd.Run()
+		check(err)
+	}
+
+	return err
+}
+
+func decodeBase64Data(data string) ([]byte, error) {
+	decodedData, err := base64.StdEncoding.DecodeString(data)
+	if err != nil {
+		return nil, fmt.Errorf("unable to decode base64: %q", err)
+	}
+
+	return decodedData, nil
+}
+
+func decodeGzipData(data string) ([]byte, error) {
+	reader, err := gzip.NewReader(strings.NewReader(data))
+	if err != nil {
+		return nil, err
+	}
+	defer reader.Close()
+
+	return io.ReadAll(reader)
+}
+
+func check(err error) {
+	if err != nil {
+		panic(err)
+	}
+}

go/test.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+/usr/bin/butane --strict ../example_files/example.bu > ../example_files/example.ign
+rm -rf /tmp/example/
+/usr/local/go/bin/go mod tidy && /usr/local/go/bin/go fmt *.go && /usr/local/go/bin/go build -o build/
+./build/injection ../example_files/example.ign