dbos-python

DBOS Python Best Practices

Guide for building reliable, fault-tolerant Python applications with DBOS durable workflows.

When to Use

Reference these guidelines when:

Rule Categories by Priority

| Priority | Category | Impact | Prefix |

|----------|----------|--------|--------|

| 1 | Lifecycle | CRITICAL | lifecycle- |

| 2 | Workflow | CRITICAL | workflow- |

| 3 | Step | HIGH | step- |

| 4 | Queue | HIGH | queue- |

| 5 | Communication | MEDIUM | comm- |

| 6 | Pattern | MEDIUM | pattern- |

| 7 | Testing | LOW-MEDIUM | test- |

| 8 | Client | MEDIUM | client- |

| 9 | Advanced | LOW | advanced- |

Critical Rules

DBOS Configuration and Launch

A DBOS application MUST configure and launch DBOS inside its main function:

import os
from dbos import DBOS, DBOSConfig

@DBOS.workflow()
def my_workflow():
    pass

if __name__ == "__main__":
    config: DBOSConfig = {
        "name": "my-app",
        "system_database_url": os.environ.get("DBOS_SYSTEM_DATABASE_URL"),
    }
    DBOS(config=config)
    DBOS.launch()

Workflow and Step Structure

Workflows are comprised of steps. Any function performing complex operations or accessing external services must be a step:

@DBOS.step()
def call_external_api():
    return requests.get("https://api.example.com").json()

@DBOS.workflow()
def my_workflow():
    result = call_external_api()
    return result

Key Constraints

How to Use

Read individual rule files for detailed explanations and examples:

references/lifecycle-config.md
references/workflow-determinism.md
references/queue-concurrency.md

References