GitHub - rodmena-limited/stabilize: Queue-Based State Machine - A lightweight workflow execution engine with DAG-based stage orchestration. Unlike simple task queues (like Celery) or advanced orchestrators (like Highway), Stabilize strikes a balance specifically optimized for high-throughput, stateful DAG execution, making it highly suitable for coordinating autonomous AI agents

pip install stabilize            # SQLite support only
pip install stabilize[postgres]  # PostgreSQL support
pip install stabilize[all]       # All features

from stabilize.models.stage import JoinType, SplitType

# OR-Split (WCP-6): Conditional multi-branch activation
StageExecution(
    ref_id="triage",
    split_type=SplitType.OR,
    split_conditions={
        "police": "emergency_type == 'crime'",
        "ambulance": "injury_severity > 0",
    },
    ...
)

# Discriminator Join (WCP-9): Fire on first upstream completion
StageExecution(
    ref_id="triage",
    join_type=JoinType.DISCRIMINATOR,
    requisite_stage_ref_ids={"check_breathing", "check_pulse"},
    ...
)

# N-of-M Join (WCP-30): Fire when 3 of 5 complete
StageExecution(
    ref_id="proceed",
    join_type=JoinType.N_OF_M,
    join_threshold=3,
    requisite_stage_ref_ids={"r1", "r2", "r3", "r4", "r5"},
    ...
)

from stabilize import Task, TaskResult

class ApprovalTask(Task):
    def execute(self, stage):
        if stage.context.get("_signal_name") == "approved":
            return TaskResult.success()
        return TaskResult.suspend()  # Wait for external signal

# Send signal to resume
from stabilize.queue.messages import SignalStage
queue.push(SignalStage(
    execution_id=workflow.id, stage_id=stage.id,
    signal_name="approved", signal_data={"user": "alice"},
    persistent=True,  # Buffered if stage not yet suspended
))

# Mutex (WCP-39): Only one stage with same key runs at a time
StageExecution(ref_id="update_db", mutex_key="shared_db", ...)

# Milestone (WCP-18): Only enabled while milestone stage is RUNNING
StageExecution(ref_id="change_route", milestone_ref_id="issue_ticket", milestone_status="RUNNING", ...)

# Deferred Choice (WCP-16): First branch to start wins
StageExecution(ref_id="agent_contact", deferred_choice_group="response", ...)
StageExecution(ref_id="escalate", deferred_choice_group="response", ...)

┌───────────────┬────────────────────┬──────────────────────┬───────────────────┐
│ Feature       │ stabilize          │ Spinnaker (Orca)     │ Airflow           │
├───────────────┼────────────────────┼──────────────────────┼───────────────────┤
│ State Storage │ Atomic (DB+Queue)  │ Atomic (Redis/SQL)   │ Atomic (SQL)      │
│ Concurrency   │ Optimistic Locking │ Distributed Lock     │ Database Row Lock │
│ Resilience    │ Queue-based (DLQ)  │ Queue-based (DLQ)    │ Scheduler Loop    │
│ Flow Control  │ 20 WCP Patterns    │ Rigid DAG            │ Rigid DAG         │
│ Complexity    │ Low (Library)      │ High (Microservices) │ High (Platform)   │
└───────────────┴────────────────────┴──────────────────────┴───────────────────┘

from stabilize import (
    Workflow, StageExecution, TaskExecution,
    SqliteWorkflowStore, SqliteQueue, QueueProcessor, Orchestrator,
    Task, TaskResult, TaskRegistry,
)

# Define a custom task
class HelloTask(Task):
    def execute(self, stage: StageExecution) -> TaskResult:
        name = stage.context.get("name", "World")
        return TaskResult.success(outputs={"greeting": f"Hello, {name}!"})

# Create a workflow
workflow = Workflow.create(
    application="my-app",
    name="Hello Workflow",
    stages=[
        StageExecution(
            ref_id="1",
            type="hello",
            name="Say Hello",
            tasks=[
                TaskExecution.create(
                    name="Hello Task",
                    implementing_class="hello",
                    stage_start=True,
                    stage_end=True,
                ),
            ],
            context={"name": "Stabilize"},
        ),
    ],
)

# Setup persistence and queue
store = SqliteWorkflowStore("sqlite:///:memory:", create_tables=True)
queue = SqliteQueue("sqlite:///:memory:")
queue._create_table()

# Register tasks
registry = TaskRegistry()
registry.register("hello", HelloTask)

# Create processor (auto-registers all default handlers)
processor = QueueProcessor(queue, store=store, task_registry=registry)

orchestrator = Orchestrator(queue)

# Run workflow
store.store(workflow)
orchestrator.start(workflow)
processor.process_all(timeout=10.0)

# Check result
result = store.retrieve(workflow.id)
print(f"Status: {result.status}")  # WorkflowStatus.SUCCEEDED
print(f"Output: {result.stages[0].outputs}")  # {'greeting': 'Hello, Stabilize!'}

from stabilize import ShellTask

registry.register("shell", ShellTask)

# Use in stage context
context = {
    "command": "npm install && npm test",
    "cwd": "/app",
    "timeout": 300,
    "env": {"NODE_ENV": "test"},
}

from stabilize import HTTPTask

registry.register("http", HTTPTask)

# GET with JSON parsing
context = {"url": "https://api.example.com/data", "parse_json": True}

# POST with JSON body
context = {"url": "https://api.example.com/users", "method": "POST", "json": {"name": "John"}}

# With authentication
context = {"url": "https://api.example.com/private", "bearer_token": "token"}

# File upload
context = {"url": "https://api.example.com/upload", "method": "POST", "upload_file": "/path/to/file.pdf"}

#     Setup
#    /     \
#  Test   Lint
#    \     /
#    Deploy

workflow = Workflow.create(
    application="my-app",
    name="CI/CD Pipeline",
    stages=[
        StageExecution(ref_id="setup", type="setup", name="Setup", ...),
        StageExecution(ref_id="test", type="test", name="Test",
                      requisite_stage_ref_ids={"setup"}, ...),
        StageExecution(ref_id="lint", type="lint", name="Lint",
                      requisite_stage_ref_ids={"setup"}, ...),
        StageExecution(ref_id="deploy", type="deploy", name="Deploy",
                      requisite_stage_ref_ids={"test", "lint"}, ...),
    ],
)

from stabilize import Task, TaskResult, TransientError

class RouterTask(Task):
    """Route to different stages based on conditions."""
    def execute(self, stage: StageExecution) -> TaskResult:
        if stage.context.get("tests_passed"):
            return TaskResult.success()
        else:
            # Jump to another stage with context
            return TaskResult.jump_to(
                "retry_stage",
                context={"retry_reason": "tests failed"}
            )

class ProgressTask(Task):
    def execute(self, stage: StageExecution) -> TaskResult:
        processed = stage.context.get("processed_items", 0)
        try:
            # Process next batch
            new_processed = process_batch(processed)
            return TaskResult.success(outputs={"total": new_processed})
        except RateLimitError:
            # Preserve progress for next retry
            raise TransientError(
                "Rate limited",
                retry_after=30,
                context_update={"processed_items": processed + 10}
            )

from stabilize.events import configure_event_sourcing, SqliteEventStore

# Enable event sourcing — handlers automatically record all state transitions
event_store = SqliteEventStore("sqlite:///events.db", create_tables=True)
configure_event_sourcing(event_store)

# Run workflows as usual — events are recorded automatically

# Subscribe to events for monitoring
from stabilize.events import get_event_bus, EventType
bus = get_event_bus()
bus.subscribe("monitor", lambda e: print(e.event_type.value))

# Replay events to reconstruct state at any point
from stabilize.events import EventReplayer
replayer = EventReplayer(event_store)
state = replayer.rebuild_workflow_state(workflow.id)

# Build analytics with projections
from stabilize.events import StageMetricsProjection
metrics = StageMetricsProjection()
bus.subscribe("metrics", metrics.apply)

# Using mg.yaml in current directory
stabilize mg-up

# Using database URL
stabilize mg-up --db-url postgres://user:pass@host:5432/dbname

# Using environment variable
MG_DATABASE_URL=postgres://user:pass@host:5432/dbname stabilize mg-up

# Check migration status
stabilize mg-status

database:
  host: localhost
  port: 5432
  user: postgres
  password: postgres
  dbname: stabilize

stabilize mg-up [--db-url URL]      Apply pending PostgreSQL migrations
stabilize mg-status [--db-url URL]  Show migration status
stabilize monitor [--db-url URL]    Real-time workflow monitoring dashboard
stabilize prompt                    Output documentation for pipeline code generation

# All tests (requires Docker for PostgreSQL)
pytest tests/ -v

# SQLite tests only (no Docker)
pytest tests/ -v -k sqlite