Initial commit of datagraph_launcher

launcher/go.mod

@@ -0,0 +1,5 @@
+module datagraph_launcher
+
+go 1.24.2
+
+require github.com/goccy/go-yaml v1.18.0

launcher/go.sum

@@ -0,0 +1,2 @@
+github.com/goccy/go-yaml v1.18.0 h1:8W7wMFS12Pcas7KU+VVkaiCng+kG8QiFeFwzFb+rwuw=
+github.com/goccy/go-yaml v1.18.0/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=

launcher/main.go

@@ -0,0 +1,113 @@
+package main
+
+import (
+	// External
+	"github.com/goccy/go-yaml"
+
+	// Standard
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path"
+)
+
+const VERSION = "v1"
+
+type DatagraphNode struct {
+	ID       int
+	Name     string
+	Children []*DatagraphNode
+	TypeName string
+	Data     struct {
+		Exec    string
+		Dynamic string
+		Inplace bool
+	}
+}
+
+type Entry struct {
+	Name     string
+	Exec     string   `yaml:",omitempty"`
+	Inplace  bool     `yaml:",omitempty"`
+	Dynamic  string   `yaml:",omitempty"`
+	Commands []*Entry `yaml:",omitempty"`
+}
+
+func (node DatagraphNode) toEntry() (e Entry) {
+	e.Name = node.Name
+	e.Exec = node.Data.Exec
+	e.Dynamic = node.Data.Dynamic
+	e.Inplace = node.Data.Inplace
+
+	for _, childNode := range node.Children {
+		childEntry := childNode.toEntry()
+		e.Commands = append(e.Commands, &childEntry)
+	}
+	return
+}
+
+func init() {
+	var flagVersion bool
+
+	flag.BoolVar(&flagVersion, "version", false, "Print version and exit")
+	flag.Parse()
+
+	if flagVersion {
+		fmt.Println(VERSION)
+		os.Exit(0)
+	}
+}
+
+func main() {
+	// Script could be run for different users and have different places where config is supposed to go.
+	dir := os.Getenv("DATAGRAPH_DIR")
+	if dir == "" {
+		fmt.Fprintf(os.Stderr, "Set env variable DATAGRAPH_DIR\n")
+		os.Exit(1)
+	}
+
+	// Make it easier for admins by creating directories automatically.
+	err := os.MkdirAll(dir, 0700)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n", err)
+		os.Exit(1)
+	}
+
+	// JSON data from datagraph is read into a data structure
+	// for further processing into the launcher
+	datagraphData, _ := io.ReadAll(os.Stdin)
+	var node DatagraphNode
+	err = json.Unmarshal(datagraphData, &node)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n", err)
+		os.Exit(1)
+	}
+
+	// Each top node is a separate file.
+	for _, topNode := range node.Children {
+		y, err := yaml.Marshal(topNode.toEntry())
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s\n", err)
+			os.Exit(1)
+		}
+
+		f, err := os.OpenFile(
+			path.Join(dir, topNode.Name+".yaml"),
+			os.O_CREATE|os.O_WRONLY|os.O_TRUNC,
+			0600,
+		)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s\n", err)
+			os.Exit(1)
+		}
+		defer f.Close()
+
+		_, err = f.Write(y)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s\n", err)
+			os.Exit(1)
+		}
+	}
+}