add config for snap (#191)

* add config for snap

* place holder

* fix build

* fit 7.2

* fix lint

* no empty

cmd/sshpiperd/snap/configgen/main.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"log"
+	"os"
+	"strings"
+)
+
+func main() {
+
+	configs := map[string]string{
+		"sshpiperd":  "../../main.go",
+		"workingdir": "../../../../plugin/workingdir/main.go",
+		"yaml":       "../../../../plugin/yaml/main.go",
+		"fixed":      "../../../../plugin/fixed/main.go",
+		"failtoban":  "../../../../plugin/failtoban/main.go",
+	}
+
+	for k, v := range configs {
+		extractFlags(k, v)
+	}
+}
+
+func extractFlags(namespace, filePath string) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+
+	fset := token.NewFileSet()
+
+	node, err := parser.ParseFile(fset, filePath, file, parser.AllErrors)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	ast.Inspect(node, func(n ast.Node) bool {
+
+		if cl, ok := n.(*ast.CompositeLit); ok {
+
+			if t, ok := cl.Type.(*ast.SelectorExpr); ok {
+
+				o, ok := t.X.(*ast.Ident)
+				if !ok {
+					return true
+				}
+
+				if o.Name != "cli" {
+					return true
+				}
+
+				if !strings.HasSuffix(t.Sel.Name, "Flag") {
+					return true
+				}
+
+				for _, v := range cl.Elts {
+					if kv, ok := v.(*ast.KeyValueExpr); ok {
+						if kv.Key.(*ast.Ident).Name == "Name" {
+							fmt.Println(namespace + "." + strings.Trim(kv.Value.(*ast.BasicLit).Value, " \""))
+						}
+					}
+				}
+			}
+		}
+		return true
+	})
+}

cmd/sshpiperd/snap/hooks/configure

@@ -0,0 +1,4 @@
+#!/bin/sh
+set -e
+
+$SNAP/launcher generate

cmd/sshpiperd/snap/launcher/doc.go

@@ -0,0 +1,2 @@
+//go:generate sh -c "go run ../configgen/main.go > configentry.txt"
+package main

cmd/sshpiperd/snap/launcher/main.go

@@ -0,0 +1,158 @@
+package main
+
+import (
+	"embed"
+	"encoding/json"
+	"log"
+	"os"
+	"os/exec"
+	"path"
+	"strings"
+)
+
+//go:embed all:*.txt
+var configentry embed.FS
+
+func main() {
+	bindir := os.Getenv("SNAP")
+	datadir := os.Getenv("SNAP_DATA")
+
+	flags := map[string][][]string{}
+	configfile := path.Join(datadir, "flags.json")
+
+	if len(os.Args) > 1 && os.Args[1] == "generate" {
+		flags = loadFromSnapctl()
+		cache, _ := json.Marshal(flags)
+		if err := os.WriteFile(configfile, cache, 0600); err != nil {
+			log.Fatal(err)
+		}
+
+		return
+	}
+
+	cache, _ := os.ReadFile(configfile)
+	_ = json.Unmarshal(cache, &flags)
+
+	cmd := exec.Command(path.Join(bindir, "sshpiperd"))
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	for _, flag := range flags["sshpiperd"] {
+		cmd.Args = append(cmd.Args, "--"+flag[0], flag[1])
+	}
+
+	for _, plugin := range flags["sshpiperd.plugins"][0] {
+		cmd.Args = append(cmd.Args, path.Join(bindir, plugin))
+		for _, flag := range flags[plugin] {
+			cmd.Args = append(cmd.Args, "--"+flag[0], flag[1])
+		}
+		cmd.Args = append(cmd.Args, "--")
+	}
+
+	log.Println("starting sshpiperd with args:", cmd)
+	_ = cmd.Run()
+}
+
+func loadFromSnapctl() map[string][][]string {
+	commondir := os.Getenv("SNAP_COMMON")
+
+	flags := map[string][][]string{}
+
+	data, err := configentry.ReadFile("configentry.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for _, line := range strings.Split(string(data), "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+
+		v, err := get(line)
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		if v == "" {
+			continue
+		}
+
+		parts := strings.Split(line, ".")
+		ns := parts[0]
+		flag := parts[1]
+
+		flags[ns] = append(flags[ns], []string{flag, v})
+	}
+
+	// known defaults
+	{
+		v, _ := get("sshpiperd.plugins")
+		if v == "" {
+			v = "workingdir"
+		}
+
+		var plugins []string
+		for _, str := range strings.Split(v, " ") {
+			str = strings.TrimSpace(str)
+			if str != "" {
+				plugins = append(plugins, str)
+			}
+		}
+
+		flags["sshpiperd.plugins"] = [][]string{plugins}
+	}
+
+	// {
+	// 	v, _ := get("sshpiperd.typescript-log-dir")
+	// 	if v == "" {
+	// 		v = "screenrecord"
+	// 		dir := path.Join(commondir, v)
+	// 		_ = os.MkdirAll(dir, 0700)
+	// 		flags["sshpiperd"] = append(flags["sshpiperd"], []string{"typescript-log-dir", dir})
+	// 	}
+	// }
+
+	{
+		v, _ := get("sshpiperd.server-key-generate-mode")
+		if v == "" {
+			v = "notexist"
+			flags["sshpiperd"] = append(flags["sshpiperd"], []string{"server-key-generate-mode", v})
+		}
+	}
+
+	{
+		v, _ := get("sshpiperd.server-key")
+		if v == "" {
+			v = "ssh_host_ed25519_key"
+			file := path.Join(commondir, v)
+			flags["sshpiperd"] = append(flags["sshpiperd"], []string{"server-key", file})
+		}
+	}
+
+	{
+		v, _ := get("workingdir.root")
+		if v == "" {
+			v = "workingdir"
+
+			dir := path.Join(commondir, v)
+			_ = os.MkdirAll(dir, 0700)
+			flags["workingdir"] = append(flags["workingdir"], []string{"root", dir})
+		}
+	}
+
+	return flags
+}
+
+func get(key string) (string, error) {
+	cmd := exec.Command("snapctl", "get", key)
+	output, err := cmd.Output()
+	if err != nil {
+		return "", err
+	}
+
+	value := string(output)
+	return strings.TrimSpace(value), nil
+}