Synapse RuntimeContext API

RuntimeContext provides logging, progress tracking, and client access for plugin actions.

Quick Reference

from synapse_sdk.plugins.context import RuntimeContext

def train(params: TrainParams, ctx: RuntimeContext) -> dict:
    # Progress tracking
    ctx.set_progress(0, 100)

    # Metrics recording
    ctx.set_metrics({'loss': 0.05}, 'training')

    # User-facing message
    ctx.log_message('Training started', 'info')

    # Event logging
    ctx.log('checkpoint', {'epoch': 5}, '/path/to/file')

    # Debug logging
    ctx.log_dev_event('Debug info', {'data': 'value'})

    # Signal completion
    ctx.end_log()

    return {'status': 'completed'}

Context Attributes

Attribute	Type	Description
ctx.logger	BaseLogger	Logger instance
ctx.env	PluginEnvironment	Environment variables
ctx.job_id	str | None	Job tracking ID
ctx.client	BackendClient | None	API client
ctx.agent_client	AgentClient | None	Ray operations client
ctx.checkpoint	dict | None	Pretrained model info

Progress Tracking

# Basic progress
ctx.set_progress(current=50, total=100)

# Progress with category (multi-phase)
ctx.set_progress(5, 10, category='download')
ctx.set_progress(3, 100, category='training')

Metrics Recording

ctx.set_metrics(
    value={'loss': 0.05, 'accuracy': 0.95},
    category='training'
)

Logging Methods

Method	Description
log(event, data, file)	Log event with data
log_message(message, context)	User-facing message
log_dev_event(message, data)	Debug/dev event
end_log()	Signal completion

Message Contexts

ctx.log_message('Success!', 'success')   # Green
ctx.log_message('Warning', 'warning')    # Yellow
ctx.log_message('Error', 'danger')       # Red
ctx.log_message('Info', 'info')          # Blue (default)

Environment Access

# Get environment variable
api_key = ctx.env.get('API_KEY', '')
debug_mode = ctx.env.get('DEBUG', 'false') == 'true'

Checkpoint Info

if ctx.checkpoint:
    model_path = ctx.checkpoint.get('path')
    category = ctx.checkpoint.get('category')  # 'base' or fine-tuned

Specialized Step Contexts

For step-based workflows, specialized contexts extend BaseStepContext:

from synapse_sdk.plugins.actions.train import TrainContext
from synapse_sdk.plugins.actions.export import ExportContext
from synapse_sdk.plugins.actions.upload import UploadContext
from synapse_sdk.plugins.actions.inference import InferenceContext, DeploymentContext
from synapse_sdk.plugins.actions.add_task_data import AddTaskDataContext

Context	Purpose	Key Attributes
TrainContext	Training workflows	dataset, model_path, model
ExportContext	Export workflows	results, exported_count, output_path
UploadContext	Upload workflows	uploaded_files, data_units
InferenceContext	Inference workflows	model, results, processed_count
DeploymentContext	Deployment workflows	serve_app_id, deployed
AddTaskDataContext	Pre-annotation workflows	task_ids, success_count, failures

All step contexts include:

• runtime_ctx - Reference to RuntimeContext
• set_progress() / set_metrics() - Auto-uses step name as category
• log() - Event logging

See step-workflow skill for details.

Additional Resources

For advanced patterns:

• references/logging-patterns.md - Advanced logging
• references/specialized-contexts.md - Step context details