81 lines
3.3 KiB
Markdown
81 lines
3.3 KiB
Markdown
# Hot-Reload Dev Script Design (dev.sh)
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## 1. Overview
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`dev.sh` is a development script that starts all backend microservices with file-watching hot-reload. When any `.go` file changes in a service's directory, only that specific service is recompiled and restarted.
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## 2. Architecture
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```
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dev.sh
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├── Load .env (same as start.sh)
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├── Start all services in dependency order (background)
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└── Run multiple concurrent file watchers (background)
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├── watcher(gateway) → monitors gateway/ → restart gateway
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├── watcher(userService) → monitors services/userService/ → restart userService
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├── watcher(assetService) → monitors services/assetService/ → restart assetService
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├── watcher(socialService) → monitors services/socialService/ → restart socialService
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├── watcher(galleryService) → monitors services/galleryService/ → restart galleryService
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└── watcher(activityService) → monitors services/activityService/ → restart activityService
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```
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## 3. Service Startup Order
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Same as `start.sh`:
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1. userService (port 20000)
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2. assetService (port 20003)
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3. socialService (port 20002)
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4. galleryService (port 20004)
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5. activityService (port 20005)
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6. gateway (port 8080)
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## 4. Watcher Behavior
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For each service:
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- **Monitor**: `<service_dir>/**/*.go`
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- **Trigger**: Any `.go` file create/modify/write event
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- **Debounce**: 300ms cooldown — after a restart is triggered, ignore further events for 300ms to avoid rapid successive rebuilds.
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- **Action** (executed inside service's own module directory, matching `start.sh`):
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1. Recompile: `cd <service_dir> && go build -o <binary> .`
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2. **Build-failure safety**: If build fails, log the error and keep the old process running
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3. Only after successful build: kill the running service process
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4. Restart with same arguments as `start.sh`
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5. Log the event to console (cyan color)
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## 5. Dependencies
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- **Mac**: `fswatch` (install via `brew install fswatch`)
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- **Linux**: `inotifywait` (install via package manager)
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If the required tool is not installed, the script prints a clear installation instruction and exits.
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## 6. Signal Handling
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- `Ctrl+C` / SIGINT / SIGTERM: Use a `trap` to catch signals — stop all services and watchers, then exit
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- On exit: Kill all service processes and watcher processes in reverse startup order (gateway first, then services)
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## 7. Logging
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- Each service logs to `/tmp/<service_name>.log` (same as start.sh)
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- Console output shows which file changed and which service was restarted
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- Hot-reload events are printed in distinct color (cyan)
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## 8. File Structure
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```
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backend/
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├── dev.sh # Main dev script (new)
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└── start.sh # Production start script (existing)
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```
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## 9. Edge Cases
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- **Build failure**: Old process keeps running; error is logged to console and `/tmp/<service>.log`
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- **Watched directory missing**: Script exits with error if monitored directory does not exist
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- **Tool not found**: Script prints installation instructions and exits
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- **Rapid file changes**: 300ms debounce prevents immediate successive rebuilds; each batch of changes triggers at most one restart
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## 10. No Changes to Existing Files
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`dev.sh` does not modify any existing files. It only reads `start.sh` for reference and adds a new file.
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