**What**
This PR introduces experimental Hot Module Replacement (HMR) for the Medusa backend, enabling developers to see code changes reflected immediately without restarting the server. This significantly improves the development experience by reducing iteration time.
### Key Features
- Hot reload support for:
- API Routes
- Workflows & Steps
- Scheduled Jobs
- Event Subscribers
- Modules
- IPC-based architecture: The dev server runs in a child process, communicating with the parent watcher via IPC. When HMR fails, the child process is killed and restarted, ensuring
clean resource cleanup.
- Recovery mechanism: Automatically recovers from broken module states without manual intervention.
- Graceful fallback: When HMR cannot handle a change (e.g., medusa-config.ts, .env), the server restarts completely.
### Architecture
```mermaid
flowchart TB
subgraph Parent["develop.ts (File Watcher)"]
W[Watch Files]
end
subgraph Child["start.ts (HTTP Server)"]
R[reloadResources]
R --> MR[ModuleReloader]
R --> WR[WorkflowReloader]
R --> RR[RouteReloader]
R --> SR[SubscriberReloader]
R --> JR[JobReloader]
end
W -->|"hmr-reload"| R
R -->|"hmr-result"| W
```
### How to enable it
Backend HMR is behind a feature flag. Enable it by setting:
```ts
// medusa-config.ts
module.exports = defineConfig({
featureFlags: {
backend_hmr: true
}
})
```
or
```bash
export MEDUSA_FF_BACKEND_HMR=true
```
or
```
// .env
MEDUSA_FF_BACKEND_HMR=true
```
Co-authored-by: Oli Juhl <59018053+olivermrbl@users.noreply.github.com>
Co-authored-by: Carlos R. L. Rodrigues <37986729+carlos-r-l-rodrigues@users.noreply.github.com>
* chore(): Cleanup and organize deps
* chore(): Cleanup and organize deps
* chore(): Cleanup and organize deps
* chore(): Cleanup and organize deps
* chore(): Cleanup and organize deps
* chore(): Cleanup and organize deps
* Create lucky-poets-scream.md
* chore(): Cleanup and organize deps
* chore(): Cleanup and organize deps
* chore(): Cleanup and organize deps
* chore(): Cleanup and organize deps
* dedupe snapshot this build
* split into 4 shard
* re configure packages integration tests
* re configure packages integration tests
* re configure packages integration tests
* re configure packages integration tests
* update scripts
* update scripts
* update scripts
* update scripts
* update scripts
* update scripts
* update scripts
* update scripts
* reduce shard for packages
RESOLVES CORE-1153
**What**
- This pr mainly lay the foundation the caching layer. It comes with a modules (built in memory cache) and a redis provider.
- Apply caching to few touch point to test
Co-authored-by: Carlos R. L. Rodrigues <37986729+carlos-r-l-rodrigues@users.noreply.github.com>
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* test(): test dynamic max workers
* Clarify test description and improve CI
PARTIALLY RESOLVES FRMW-2876
**What**
Fix wrong usage of the `subscriberId` in the event bus. It happens that the subscriber id coming from the context was not used at all. This issue lead to duplicated event subscriber with the same subscriber id, it also prevent unsubscribing from event since rand id will be assigned.
**NOTE**
This PR does not handle overide strategy for subscribers with the same id. this still needs to be discussed
