Event Contracts Documentation¶

Version: 1.0 Date: November 8, 2025 Phase: Phase 2 - Circular Dependency Resolution

Overview¶

Printernizer uses an event-driven architecture to decouple services and prevent circular dependencies. This document provides a comprehensive reference of all events in the system, their payload schemas, emitters, and subscribers.

Event System Architecture¶

Core Components¶

EventService (src/services/event_service.py): Central event bus that manages subscriptions and event emission
Event Emitters: Services that publish events when state changes occur
Event Subscribers: Services that react to events asynchronously

Event Flow Pattern¶

[Service A] → emit_event() → [EventService] → notify subscribers → [Service B, C, D...]

Key Principles¶

Decoupling: Services communicate through events, not direct method calls
Asynchronous: Event handlers run asynchronously to avoid blocking
Error Isolation: Exceptions in handlers don't propagate to emitters
Late Binding: Services set dependencies via setters to avoid circular imports

Event Categories¶

1. Printer Connection Events¶

2. Printer Monitoring Events¶

3. Printer Control Events¶

4. File Discovery Events¶

5. File Download Events¶

6. File Processing Events¶

7. Job Lifecycle Events¶

8. Library Management Events¶

9. Material Management Events¶

11. Background Monitoring Events (EventService)¶

1. Printer Connection Events¶

`printer_connected`¶

Emitted by: PrinterConnectionService, EventService (background monitoring)

When: A printer successfully connects and becomes available

Payload Schema:

{
    "printer_id": str,        # Unique printer identifier
    "name": str,              # Printer display name
    "type": str,              # Printer type ("bambu_lab" or "prusa")
    "timestamp": str          # ISO 8601 timestamp
}

Subscribers: None (informational)

Usage Example:

await self.event_service.emit_event("printer_connected", {
    "printer_id": "bambu_001",
    "name": "Bambu Lab A1",
    "type": "bambu_lab",
    "timestamp": "2025-11-08T10:30:00Z"
})

Error Handling: Connection failures do not emit this event; see printer_connection_progress for failure status

`printer_disconnected`¶

Emitted by: PrinterConnectionService, EventService (background monitoring)

When: A printer disconnects or becomes unavailable

Payload Schema:

{
    "printer_id": str,        # Unique printer identifier
    "name": str,              # Printer display name
    "timestamp": str          # ISO 8601 timestamp
}

Subscribers: None (informational)

Usage Example:

await self.event_service.emit_event("printer_disconnected", {
    "printer_id": "bambu_001",
    "name": "Bambu Lab A1",
    "timestamp": "2025-11-08T11:45:00Z"
})

`printer_connection_progress`¶

Emitted by: PrinterConnectionService

When: Connection state changes during connection attempt

Payload Schema:

{
    "printer_id": str,        # Unique printer identifier
    "status": str,            # One of: "connecting", "connected", "failed", "monitoring", "error"
    "timestamp": str,         # ISO 8601 timestamp
    "message": str            # Optional status message (present for "failed", "error")
}

Subscribers: None (informational, used for real-time UI updates)

Usage Example:

# Connection attempt started
await self.event_service.emit_event("printer_connection_progress", {
    "printer_id": "prusa_001",
    "status": "connecting",
    "timestamp": "2025-11-08T10:30:00Z"
})

# Connection failed
await self.event_service.emit_event("printer_connection_progress", {
    "printer_id": "prusa_001",
    "status": "failed",
    "timestamp": "2025-11-08T10:30:15Z",
    "message": "Connection timeout after 30s"
})

Status Values: - connecting: Initial connection attempt - connected: Successfully connected - failed: Connection attempt failed (transient error) - monitoring: Monitoring started successfully - error: Unrecoverable error occurred

2. Printer Monitoring Events¶

`printer_status_update`¶

Emitted by: PrinterMonitoringService

When: Printer status changes (after processing status update from printer)

Payload Schema:

{
    "printer_id": str,            # Unique printer identifier
    "status": str,                # Printer status (e.g., "printing", "idle", "paused")
    "temperature": dict,          # Temperature data (nozzle, bed, chamber)
    "progress": int,              # Print progress percentage (0-100)
    "current_job": Optional[str], # Current job filename (if printing)
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational, used for real-time UI updates)

Usage Example:

await self.event_service.emit_event("printer_status_update", {
    "printer_id": "bambu_001",
    "status": "printing",
    "temperature": {
        "nozzle": 220.0,
        "bed": 60.0,
        "chamber": 35.0
    },
    "progress": 45,
    "current_job": "model.3mf",
    "timestamp": "2025-11-08T10:35:00Z"
})

Frequency: Emitted after every status update processed (typically every few seconds during printing)

`printer_monitoring_started`¶

Emitted by: PrinterMonitoringService

When: Monitoring begins for a specific printer

Payload Schema:

{
    "printer_id": str,        # Unique printer identifier
    "timestamp": str          # ISO 8601 timestamp
}

Subscribers: None (informational)

`printer_monitoring_stopped`¶

Emitted by: PrinterMonitoringService

When: Monitoring stops for a specific printer

Payload Schema:

{
    "printer_id": str,        # Unique printer identifier
    "timestamp": str          # ISO 8601 timestamp
}

Subscribers: None (informational)

3. Printer Control Events¶

`print_paused`¶

Emitted by: PrinterControlService

When: Print job successfully paused

Payload Schema:

{
    "printer_id": str,        # Unique printer identifier
    "timestamp": str          # ISO 8601 timestamp
}

Subscribers: None (informational)

`print_resumed`¶

Emitted by: PrinterControlService

When: Print job successfully resumed

Payload Schema:

{
    "printer_id": str,        # Unique printer identifier
    "timestamp": str          # ISO 8601 timestamp
}

Subscribers: None (informational)

`print_stopped`¶

Emitted by: PrinterControlService

When: Print job successfully stopped/cancelled

Payload Schema:

{
    "printer_id": str,        # Unique printer identifier
    "timestamp": str          # ISO 8601 timestamp
}

Subscribers: None (informational)

4. File Discovery Events¶

`files_discovered`¶

Emitted by: FileDiscoveryService, EventService (background monitoring)

When: File discovery completes on printer(s) or local folders

Payload Schema:

{
    "printer_id": str,            # Printer identifier (or "all" for multi-printer scans)
    "files": List[dict],          # List of discovered/stored files
    "total_found": int,           # Total files found
    "new_files": int,             # Number of new files added to database
    "existing_files": int,        # Number of files already tracked
    "timestamp": str,             # ISO 8601 timestamp

    # Optional fields (EventService background discovery)
    "discovery_results": dict,    # Per-printer discovery results
    "new_files": List[dict]       # Detailed new file information
}

Subscribers: None (informational)

Usage Example:

name="__codelineno-15-1" href="#__codelineno-15-1"># From FileDiscoveryService class="k">await self.event_service.emit_event("files_discovered", { "printer_id": "bambu_001", "files": [ {"filename": "model1.3mf", "file_size": 1024000}, {"filename": "model2.gcode", "file_size": 2048000} ], "total_found": 2, "new_files": 1, "existing_files": 1, "timestamp": "2025-11-08T10:40:00Z" class="p">}) class="c1"># From EventService background task class="k">await self.event_service.emit_event("files_discovered", { "timestamp": "2025-11-08T10:40:00Z", "new_files": [ { "printer_id": "bambu_001", "printer_name": "Bambu Lab A1", "filename": "model.3mf", "file_size": 1024000, "file_type": "3mf", "discovered_at": "2025-11-08T10:40:00Z" } ], "discovery_results": { "bambu_001": { "printer_name": "Bambu Lab A1", "files_found": 5, "success": True } }, "total_new_files": 1 class="p">})

`file_sync_complete`¶

Emitted by: FileDiscoveryService

When: File synchronization completes for a printer (including cleanup of removed files)

Payload Schema:

{
    "printer_id": str,            # Unique printer identifier
    "files_added": int,           # Number of files added
    "files_removed": int,         # Number of files marked as removed
    "total_files": int,           # Total files currently tracked
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`new_files_found`¶

Emitted by: EventService (background monitoring)

When: New files are discovered during background scan (subset of files_discovered)

Payload Schema:

{
    "timestamp": str,             # ISO 8601 timestamp
    "files": List[dict],          # List of new files with details
    "count": int                  # Number of new files
}

Subscribers: None (informational, triggers UI notifications)

5. File Download Events¶

`file_download_started`¶

Emitted by: FileDownloadService

When: File download from printer begins

Payload Schema:

{
    "printer_id": str,            # Unique printer identifier
    "filename": str,              # Name of file being downloaded
    "file_size": Optional[int],   # File size in bytes (if known)
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational, used for download progress UI)

`file_download_complete`¶

Emitted by: FileDownloadService

When: File download successfully completes

Payload Schema:

{
    "printer_id": str,            # Unique printer identifier
    "filename": str,              # Name of downloaded file
    "file_id": str,               # Database file ID
    "file_path": str,             # Local path to downloaded file
    "file_size": int,             # File size in bytes
    "download_time": float,       # Download duration in seconds
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`file_download_failed`¶

Emitted by: FileDownloadService

When: File download fails

Payload Schema:

{
    "printer_id": str,            # Unique printer identifier
    "filename": str,              # Name of file that failed to download
    "error": str,                 # Error message
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational, triggers UI error notifications)

6. File Processing Events¶

`file_needs_thumbnail_processing`¶

Emitted by: FileDownloadService

When: File download completes and file needs thumbnail extraction

Payload Schema:

{
    "file_id": str,               # Database file ID
    "file_path": str              # Local path to downloaded file
}

Subscribers: FileThumbnailService (listens and processes thumbnails)

Usage: This is a command event that triggers thumbnail processing

`file_thumbnails_processed`¶

Emitted by: FileThumbnailService

When: Thumbnail extraction completes successfully

Payload Schema:

{
    "file_id": str,               # Database file ID
    "file_path": str,             # Local path to file
    "thumbnails": dict,           # Thumbnail paths by size
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

Thumbnail Structure:

{
    "thumbnails": {
        "small": "/path/to/small.jpg",
        "medium": "/path/to/medium.jpg",
        "large": "/path/to/large.jpg"
    }
}

Note: Event thumbnail_processing_failed is mentioned in docstrings but not currently implemented.

`file_metadata_extracted`¶

Emitted by: FileMetadataService

When: Metadata extraction completes successfully

Payload Schema:

{
    "file_id": str,               # Database file ID
    "file_path": str,             # Local path to file
    "metadata": dict,             # Extracted metadata
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

Metadata Structure:

{
    "metadata": {
        "print_time": 7200,       # Estimated print time in seconds
        "filament_used": 125.5,   # Filament used in grams
        "layer_height": 0.2,      # Layer height in mm
        "infill": 20,             # Infill percentage
        # ... additional metadata fields
    }
}

Note: Event metadata_extraction_failed is mentioned in docstrings but not currently implemented.

`file_deleted`¶

Emitted by: FileService

When: File is successfully deleted from system

Payload Schema:

{
    "file_id": str,               # Database file ID
    "filename": str,              # Name of deleted file
    "printer_id": Optional[str],  # Printer ID (if applicable)
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`thumbnail_cached`¶

Emitted by: ThumbnailService

When: External thumbnail is downloaded and cached

Payload Schema:

{
    "url": str,                   # Original thumbnail URL
    "cache_path": str,            # Local cache path
    "source_type": str            # Source type (e.g., "makerworld", "printables")
}

Subscribers: None (informational)

`file_watcher`¶

Emitted by: FileWatcherService

When: File system changes detected in watched folders

Payload Schema:

{
    "event_type": str,            # "created", "modified", "deleted", "moved"
    "path": str,                  # File path
    "is_directory": bool,         # Whether path is directory
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational, triggers re-scan)

7. Job Lifecycle Events¶

`job_created`¶

Emitted by: JobService, EventService (background monitoring as job_started)

When: New print job is created in database

Payload Schema:

{
    "job_id": str,                # Unique job identifier
    "printer_id": str,            # Printer identifier
    "job_name": str,              # Job/file name
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`job_started`¶

Emitted by: EventService (background monitoring)

When: Job transitions to "running" status

Payload Schema:

{
    "job_id": str,                # Unique job identifier
    "printer_id": str,            # Printer identifier
    "job_name": str,              # Job/file name
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`job_status_changed`¶

Emitted by: JobService

When: Job status is explicitly updated via API

Payload Schema:

{
    "job_id": str,                # Unique job identifier
    "status": str,                # New status value
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`job_progress_updated`¶

Emitted by: JobService

When: Job progress is updated

Payload Schema:

{
    "job_id": str,                # Unique job identifier
    "progress": int,              # Progress percentage (0-100)
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`job_completed`¶

Emitted by: EventService (background monitoring)

When: Job transitions to terminal status ("completed", "failed", "cancelled")

Payload Schema:

{
    "job_id": str,                # Unique job identifier
    "printer_id": str,            # Printer identifier
    "job_name": str,              # Job/file name
    "status": str,                # Final status ("completed", "failed", "cancelled")
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`job_deleted`¶

Emitted by: JobService

When: Job is deleted from database

Payload Schema:

{
    "job_id": str,                # Unique job identifier
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

8. Library Management Events¶

`library_file_added`¶

Emitted by: LibraryService

When: File is added to user's library

Payload Schema:

{
    "checksum": str,              # File checksum (unique identifier)
    "filename": str,              # Original filename
    "file_size": int,             # File size in bytes
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`library_file_deleted`¶

Emitted by: LibraryService

When: File is removed from user's library

Payload Schema:

{
    "checksum": str,              # File checksum
    "filename": str,              # Original filename
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

9. Material Management Events¶

`material_created`¶

Emitted by: MaterialService

When: New material/filament spool is added

Payload Schema:

{
    "material": dict              # Complete material object (Material.__dict__)
}

Subscribers: None (informational)

`material_updated`¶

Emitted by: MaterialService

When: Material/spool information is updated

Payload Schema:

{
    "material": dict              # Updated material object (Material.__dict__)
}

Subscribers: None (informational)

`material_deleted`¶

Emitted by: MaterialService

When: Material/spool is deleted

Payload Schema:

{
    "material_id": str            # Unique material identifier
}

Subscribers: None (informational)

`material_low_stock`¶

Emitted by: MaterialService

When: Material remaining drops below 20%

Payload Schema:

{
    "material_id": str,           # Unique material identifier
    "remaining_percentage": float, # Remaining material percentage
    "material_name": str,         # Material display name
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational, triggers notifications)

`trending_updated`¶

Emitted by: TrendingService

When: Trending models are refreshed from external platforms

Payload Schema:

{
    "platforms": List[str],       # Platforms updated (e.g., ["makerworld", "printables"])
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

`idea_created_from_trending`¶

Emitted by: TrendingService

When: User creates an idea from a trending model

Payload Schema:

{
    "idea_id": str,               # Created idea ID
    "trending_id": str,           # Source trending model ID
    "platform": str,              # Source platform
    "timestamp": str              # ISO 8601 timestamp
}

Subscribers: None (informational)

11. Background Monitoring Events (EventService)¶

These events are emitted by EventService's internal background monitoring tasks.

`printer_status`¶

Emitted by: EventService (background monitoring task)

When: Background printer status check completes (every 30 seconds)

Payload Schema:

{
    "timestamp": str,             # ISO 8601 timestamp
    "printers": List[dict],       # Status of all printers
    "status_changes": List[dict]  # Printers with status changes
}

Printers Array Structure:

{
    "printer_id": str,
    "name": str,
    "type": str,
    "status": str,                # "online", "offline", "unknown"
    "temperature": dict,
    "progress": int,
    "current_job": Optional[str],
    "last_seen": str
}

Status Changes Array Structure:

{
    "printer_id": str,
    "old_status": str,
    "new_status": str,
    "timestamp": str
}

Subscribers: None (informational)

`job_update`¶

Emitted by: EventService (background monitoring task)

When: Background job status check completes (every 10 seconds)

Payload Schema:

{
    "timestamp": str,             # ISO 8601 timestamp
    "active_jobs": int,           # Number of active jobs
    "job_updates": List[dict]     # Jobs with status/progress changes
}

Job Updates Array Structure:

{
    "job_id": str,
    "printer_id": str,
    "job_name": str,
    "old_status": Optional[str],  # Present if status changed
    "new_status": Optional[str],  # Present if status changed
    "status": str,                # Current status
    "old_progress": Optional[int],# Present if progress changed significantly
    "new_progress": Optional[int],# Present if progress changed significantly
    "progress": int,              # Current progress
    "timestamp": str
}

Subscribers: None (informational)

Error Handling in Event System¶

Event Handler Exceptions¶

Exceptions in event handlers are caught and logged by EventService but do not propagate to the emitter:

# In EventService.emit_event()
for handler in handlers:
    try:
        if asyncio.iscoroutinefunction(handler):
            await handler(data)
        else:
            handler(data)
    except Exception as e:
        logger.error("Error in event handler",
                   event_type=event_type, error=str(e))

Best Practices: - Handlers should implement their own error handling - Log errors with context for debugging - Don't let exceptions propagate to event system

Missing Events (Not Currently Implemented)¶

The following events are mentioned in service docstrings but not currently emitted:

thumbnail_processing_failed (FileThumbnailService)
Should be emitted when thumbnail extraction fails
Recommended payload: {"file_id": str, "error": str, "timestamp": str}
metadata_extraction_failed (FileMetadataService)
Should be emitted when metadata extraction fails
Recommended payload: {"file_id": str, "error": str, "timestamp": str}
auto_download_triggered (PrinterMonitoringService)
Mentioned in prompt but not implemented
Could be emitted when auto-download starts for current job
auto_download_failed (PrinterMonitoringService)
Mentioned in prompt but not implemented
Currently only logs warnings, could emit event for UI notification

Recommendation: Implement these events for consistency and better error visibility.

Event Timing and Ordering¶

Guarantees¶

Order Preservation: Events emitted by same service are processed in order
Async Execution: Handlers run concurrently, no guaranteed inter-handler ordering
Fire-and-Forget: Emitters don't wait for handler completion

No Guarantees¶

Cross-Service Ordering: Events from different services may arrive in any order
Handler Completion: Emitter doesn't wait for handlers to finish
Delivery: If no subscribers, event is silently discarded

Timing Examples¶

File Download Workflow:

t=0s:   file_download_started
t=5s:   file_download_complete
t=5.1s: file_needs_thumbnail_processing  # Triggered by download complete
t=7s:   file_thumbnails_processed        # Async processing completes

Job Monitoring Workflow:

t=0s:   job_status_changed → "running"
t=1s:   job_started                      # Background monitoring detects
t=10s:  job_progress_updated → 10%
t=20s:  job_progress_updated → 20%
...
t=100s: job_status_changed → "completed"
t=101s: job_completed                    # Background monitoring detects

Subscription Patterns¶

def __init__(self, event_service: EventService):
    self.event_service = event_service

    # Subscribe to events
    self.event_service.subscribe("file_needs_thumbnail_processing",
                                 self._handle_thumbnail_request)

async def _handle_thumbnail_request(self, data: Dict[str, Any]):
    """Handle thumbnail processing request."""
    file_id = data["file_id"]
    file_path = data["file_path"]
    await self._process_thumbnails(file_id, file_path)

Emit Events¶

async def download_file(self, printer_id: str, filename: str):
    # Emit start event
    await self.event_service.emit_event("file_download_started", {
        "printer_id": printer_id,
        "filename": filename,
        "timestamp": datetime.now().isoformat()
    })

    try:
        # ... perform download ...

        # Emit success event
        await self.event_service.emit_event("file_download_complete", {
            "printer_id": printer_id,
            "filename": filename,
            "file_id": file_id,
            "timestamp": datetime.now().isoformat()
        })
    except Exception as e:
        # Emit failure event
        await self.event_service.emit_event("file_download_failed", {
            "printer_id": printer_id,
            "filename": filename,
            "error": str(e),
            "timestamp": datetime.now().isoformat()
        })

Best Practices¶

For Event Emitters¶

Use structured payloads with consistent field names
Include timestamps for all events
Add context (IDs, names) for debugging
Emit events after state changes complete
Don't rely on subscribers - events are fire-and-forget

For Event Subscribers¶

Handle errors internally - don't let exceptions propagate
Log with context for debugging
Keep handlers fast - offload heavy work to background tasks
Check payload schema - validate required fields exist
Be idempotent - handlers may be called multiple times

For Event Naming¶

Use past tense for completed actions (file_downloaded, not download_file)
Use present tense for state updates (printer_status_update)
Be specific (file_download_complete vs file_complete)
Group related events with prefixes (job_created, job_deleted, job_updated)

Debugging Events¶

View Event Counts¶

# Get event service status
status = event_service.get_status()
print(status["event_counts"])

# Output:
# {
#     'printer_status': 120,
#     'job_update': 240,
#     'files_discovered': 8,
#     'printer_connected': 2,
#     'printer_disconnected': 1,
#     'job_started': 5,
#     'job_completed': 4,
#     'new_files_found': 3
# }

Enable Event Logging¶

Set log level to DEBUG to see all event emissions:

import structlog
logger = structlog.get_logger()
logger.setLevel("DEBUG")

# Will log:
# event="emit_event" event_type="file_download_started" printer_id="bambu_001"

Migration Guide¶

Adding New Events¶

Define event contract in this document
Add event emission in service code
Add subscribers (if needed)
Update tests to verify event emission
Update EVENT_FLOWS.md with event flow

Deprecating Events¶

Mark as deprecated in this document
Add deprecation warning in emitter code
Wait 2+ versions before removing
Remove event and update documentation

Event Contracts Documentation¶

Overview¶

Event System Architecture¶

Core Components¶

Event Flow Pattern¶

Key Principles¶

Event Categories¶

1. Printer Connection Events¶

2. Printer Monitoring Events¶

3. Printer Control Events¶

4. File Discovery Events¶

5. File Download Events¶

6. File Processing Events¶

7. Job Lifecycle Events¶

8. Library Management Events¶

9. Material Management Events¶

10. Trending & External Content Events¶

11. Background Monitoring Events (EventService)¶

1. Printer Connection Events¶

printer_connected¶

printer_disconnected¶

printer_connection_progress¶

2. Printer Monitoring Events¶

printer_status_update¶

printer_monitoring_started¶

printer_monitoring_stopped¶

3. Printer Control Events¶

print_paused¶

print_resumed¶

print_stopped¶

4. File Discovery Events¶

files_discovered¶

file_sync_complete¶

new_files_found¶

5. File Download Events¶

file_download_started¶

file_download_complete¶

file_download_failed¶

6. File Processing Events¶

file_needs_thumbnail_processing¶

file_thumbnails_processed¶

file_metadata_extracted¶

file_deleted¶

thumbnail_cached¶

file_watcher¶

7. Job Lifecycle Events¶

job_created¶

job_started¶

job_status_changed¶

job_progress_updated¶

job_completed¶

job_deleted¶

8. Library Management Events¶

library_file_added¶

library_file_deleted¶

9. Material Management Events¶

material_created¶

material_updated¶

material_deleted¶

material_low_stock¶

10. Trending & External Content Events¶

trending_updated¶

idea_created_from_trending¶

11. Background Monitoring Events (EventService)¶

printer_status¶

job_update¶

Error Handling in Event System¶

Event Handler Exceptions¶

Missing Events (Not Currently Implemented)¶

Event Timing and Ordering¶

Guarantees¶

No Guarantees¶

Timing Examples¶

Subscription Patterns¶

Subscribe to Events¶

Emit Events¶

Best Practices¶

For Event Emitters¶

For Event Subscribers¶

For Event Naming¶

`printer_connected`¶

`printer_disconnected`¶

`printer_connection_progress`¶

`printer_status_update`¶

`printer_monitoring_started`¶

`printer_monitoring_stopped`¶

`print_paused`¶

`print_resumed`¶

`print_stopped`¶

`files_discovered`¶

`file_sync_complete`¶

`new_files_found`¶

`file_download_started`¶

`file_download_complete`¶

`file_download_failed`¶

`file_needs_thumbnail_processing`¶

`file_thumbnails_processed`¶

`file_metadata_extracted`¶

`file_deleted`¶

`thumbnail_cached`¶

`file_watcher`¶

`job_created`¶

`job_started`¶

`job_status_changed`¶

`job_progress_updated`¶

`job_completed`¶

`job_deleted`¶

`library_file_added`¶

`library_file_deleted`¶

`material_created`¶

`material_updated`¶

`material_deleted`¶

`material_low_stock`¶

`trending_updated`¶

`idea_created_from_trending`¶

`printer_status`¶

`job_update`¶