From 4aced0920284c30fce4400a0e7d4812dce4ea03f Mon Sep 17 00:00:00 2001
From: Matt Johnson-Pint <mjp@hypermode.com>
Date: Fri, 24 Jan 2025 17:21:10 -0800
Subject: [PATCH] fix: separate modusdb instance by app (#729)

---
 .gitignore                 |  5 +--
 .trunk/configs/cspell.json |  1 +
 CHANGELOG.md               |  4 +++
 runtime/db/modusdb.go      | 69 ++++++++++++++++++++++++++++++++++----
 4 files changed, 70 insertions(+), 9 deletions(-)

diff --git a/.gitignore b/.gitignore
index 6faf0c95..52030c1c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,13 +12,14 @@
 *.gz
 *.zip
 
-# Ignore Go debuger and generated files
+# Ignore Go debugger and generated files
 __debug_bin*
 *_generated.go
 *.generated.go
 
-# Ignore build output directories
+# Ignore build output directories and modus databases
 build/
+.modusdb/
 
 # Ignore node_modules folders
 node_modules/
diff --git a/.trunk/configs/cspell.json b/.trunk/configs/cspell.json
index f3e77e02..3d95a8ae 100644
--- a/.trunk/configs/cspell.json
+++ b/.trunk/configs/cspell.json
@@ -117,6 +117,7 @@
     "millis",
     "minilm",
     "modfile",
+    "modusdb",
     "Msgf",
     "mydb",
     "mydgraph",
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c3095539..ff22b3aa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Change Log
 
+## 2025-01-24 - Runtime 0.17.1
+
+- fix: separate modusdb instance by app [#729](https://github.com/hypermodeinc/modus/pull/729)
+
 ## 2025-01-24 - Runtime 0.17.0
 
 - feat: add modusdb model tracing for local dev
diff --git a/runtime/db/modusdb.go b/runtime/db/modusdb.go
index eb12ccb8..3ab384c1 100644
--- a/runtime/db/modusdb.go
+++ b/runtime/db/modusdb.go
@@ -10,7 +10,10 @@
 package db
 
 import (
+	"bufio"
 	"context"
+	"errors"
+	"os"
 	"path/filepath"
 	"runtime"
 
@@ -22,13 +25,26 @@ import (
 var GlobalModusDbEngine *modusdb.Engine
 
 func InitModusDb(ctx context.Context) {
-	if app.IsDevEnvironment() && runtime.GOOS != "windows" {
-		dataDir := filepath.Join(app.ModusHomeDir(), "data")
-		if eng, err := modusdb.NewEngine(modusdb.NewDefaultConfig(dataDir)); err != nil {
-			logger.Fatal(ctx).Err(err).Msg("Failed to initialize modusdb.")
-		} else {
-			GlobalModusDbEngine = eng
-		}
+	if !app.IsDevEnvironment() || runtime.GOOS == "windows" {
+		// ModusDB should only be initialized in dev environment,
+		// and currently does not work on Windows.
+		return
+	}
+
+	var dataDir string
+	appPath := app.Config().AppPath()
+	if filepath.Base(appPath) == "build" {
+		// this keeps the data directory outside of the build directory
+		dataDir = filepath.Join(appPath, "..", ".modusdb")
+		addToGitIgnore(ctx, filepath.Dir(appPath))
+	} else {
+		dataDir = filepath.Join(appPath, ".modusdb")
+	}
+
+	if eng, err := modusdb.NewEngine(modusdb.NewDefaultConfig(dataDir)); err != nil {
+		logger.Fatal(ctx).Err(err).Msg("Failed to initialize modusdb.")
+	} else {
+		GlobalModusDbEngine = eng
 	}
 }
 
@@ -37,3 +53,42 @@ func CloseModusDb(ctx context.Context) {
 		GlobalModusDbEngine.Close()
 	}
 }
+
+func addToGitIgnore(ctx context.Context, rootPath string) {
+	gitIgnorePath := filepath.Join(rootPath, ".gitignore")
+	gitIgnoreContents := ".modusdb/"
+
+	// if .gitignore file does not exist, create it and add .modusdb/ to it
+	if _, err := os.Stat(gitIgnorePath); errors.Is(err, os.ErrNotExist) {
+		if err := os.WriteFile(gitIgnorePath, []byte(gitIgnoreContents+"\n"), 0644); err != nil {
+			logger.Err(ctx, err).Msg("Failed to create .gitignore file.")
+		}
+		return
+	}
+
+	// check if .modusdb/ is already in the .gitignore file
+	file, err := os.Open(gitIgnorePath)
+	if err != nil {
+		logger.Err(ctx, err).Msg("Failed to open .gitignore file.")
+		return
+	}
+	defer file.Close()
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		if scanner.Text() == gitIgnoreContents {
+			// found .modusdb/ in the file
+			return
+		}
+	}
+
+	// .modusdb/ is not in the file, so append it
+	file, err = os.OpenFile(gitIgnorePath, os.O_APPEND|os.O_WRONLY, 0644)
+	if err != nil {
+		logger.Err(ctx, err).Msg("Failed to open .gitignore file.")
+		return
+	}
+	defer file.Close()
+	if _, err := file.WriteString("\n" + gitIgnoreContents + "\n"); err != nil {
+		logger.Err(ctx, err).Msg("Failed to append .modusdb/ to .gitignore file.")
+	}
+}