[plugins] Allow local non-compiled plugins (#1224)

## Summary

This change allows users to add their own plugins using `devbox.json`
`include` field (see example). It now supports all plugin fields
(including services).

Fixed: Issue where editing plugin would not be reflected.

## How was it tested?

```bash
devbox run run_test -c examples/plugins/local
MY_FOO_VAR is set to 'BAR'
devbox services up
```

Author: mikeland73

devbox.lock

@@ -17,4 +17,4 @@
       "version": "1.52.2"
     }
   }
-}
+}

examples/plugins/local/README.md

@@ -0,0 +1,7 @@
+# Custom plugin example
+
+Shows how to write custom local plugin. Plugins can:
+
+* Install packages
+* Create templatized files (including flakes)
+* Declare services (using process-compose)

examples/plugins/local/devbox.json

@@ -0,0 +1,16 @@
+{
+  "packages": [],
+  "shell": {
+    "init_hook": [
+      "echo 'Welcome to devbox!' > /dev/null"
+    ],
+    "scripts": {
+      "run_test": [
+        "./test.sh"
+      ]
+    }
+  },
+  "include": [
+    "path:my-plugin/my-plugin.json"
+  ]
+}

examples/plugins/local/devbox.lock

@@ -0,0 +1,6 @@
+{
+  "lockfile_version": "1",
+  "packages": {
+    "path:my-plugin/my-plugin.json": {}
+  }
+}

examples/plugins/local/my-plugin/my-plugin.json

@@ -0,0 +1,13 @@
+{
+  "name": "my-plugin",
+  "version": "0.0.1",
+  "readme": "Example custom plugin",
+  "env": {
+    "MY_FOO_VAR": "BAR"
+  },
+  "create_files": {
+    "{{ .Virtenv }}/empty-dir": "",
+    "{{ .Virtenv }}/some-file": "some-file.txt",
+    "{{ .Virtenv }}/process-compose.yaml": "process-compose.yaml"
+  }
+}

examples/plugins/local/my-plugin/process-compose.yaml

@@ -0,0 +1,7 @@
+version: "0.5"
+
+processes:
+  my-plugin-service:
+    command: echo "success" && tail -f /dev/null
+    availability:
+      restart: "always"

examples/plugins/local/my-plugin/some-file.txt

@@ -0,0 +1 @@
+some data

examples/plugins/local/test.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+if [ -z "$MY_FOO_VAR" ]; then
+  echo "MY_FOO_VAR environment variable is not set."
+  exit 1
+else
+ echo "MY_FOO_VAR is set to '$MY_FOO_VAR'"
+fi

internal/impl/devbox.go

@@ -127,12 +127,15 @@ func (d *Devbox) Config() *devconfig.Config {
 }
 
 func (d *Devbox) ConfigHash() (string, error) {
-	hashes := lo.Map(d.PackagesAsInputs(), func(i *devpkg.Package, _ int) string { return i.Hash() })
+	pkgHashes := lo.Map(d.PackagesAsInputs(), func(i *devpkg.Package, _ int) string { return i.Hash() })
+	includeHashes := lo.Map(d.Includes(), func(i plugin.Includable, _ int) string { return i.Hash() })
 	h, err := d.cfg.Hash()
 	if err != nil {
 		return "", err
 	}
-	return cuecfg.Hash(h + strings.Join(hashes, ""))
+	return cuecfg.Hash(
+		h + strings.Join(pkgHashes, "") + strings.Join(includeHashes, ""),
+	)
 }
 
 func (d *Devbox) NixPkgsCommitHash() string {
@@ -919,6 +922,16 @@ func (d *Devbox) PackagesAsInputs() []*devpkg.Package {
 	return devpkg.PackageFromStrings(d.Packages(), d.lockfile)
 }
 
+func (d *Devbox) Includes() []plugin.Includable {
+	includes := []plugin.Includable{}
+	for _, includePath := range d.cfg.Include {
+		if include, err := d.pluginManager.ParseInclude(includePath); err == nil {
+			includes = append(includes, include)
+		}
+	}
+	return includes
+}
+
 func (d *Devbox) HasDeprecatedPackages() bool {
 	for _, pkg := range d.PackagesAsInputs() {
 		if pkg.IsLegacy() {

internal/plugin/files.go

@@ -4,20 +4,28 @@
 package plugin
 
 import (
+	"os"
 	"regexp"
 	"strings"
 
 	"github.com/pkg/errors"
-	"go.jetpack.io/devbox/internal/devpkg"
 	"go.jetpack.io/devbox/plugins"
 )
 
-func getConfigIfAny(pkg *devpkg.Package, projectDir string) (*config, error) {
+func getConfigIfAny(pkg Includable, projectDir string) (*config, error) {
 	configFiles, err := plugins.BuiltIn.ReadDir(".")
 	if err != nil {
 		return nil, errors.WithStack(err)
 	}
 
+	if local, ok := pkg.(*localPlugin); ok {
+		content, err := os.ReadFile(local.path)
+		if err != nil && !os.IsNotExist(err) {
+			return nil, errors.WithStack(err)
+		}
+		return buildConfig(pkg, projectDir, string(content))
+	}
+
 	for _, file := range configFiles {
 		if file.IsDir() || strings.HasSuffix(file.Name(), ".go") {
 			continue
@@ -44,6 +52,9 @@ func getConfigIfAny(pkg *devpkg.Package, projectDir string) (*config, error) {
 	return nil, nil
 }
 
-func getFileContent(contentPath string) ([]byte, error) {
+func getFileContent(pkg Includable, contentPath string) ([]byte, error) {
+	if local, ok := pkg.(*localPlugin); ok {
+		return os.ReadFile(local.contentPath(contentPath))
+	}
 	return plugins.BuiltIn.ReadFile(contentPath)
 }