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DBOS Class

The DBOS class is a singleton—you must instantiate it (by calling its constructor) exactly once in a program's lifetime. Here, we document its constructor and lifecycle methods. Decorators are documented here and context methods and variables here.

class dbos.DBOS​

DBOS(
    *,
    config: Optional[DBOSConfig] = None,
)

Parameters:

launch​

DBOS.launch()

Launch DBOS, initializing database connections and starting queues and scheduled workflows. Should be called after all decorators run. You should not run a DBOS workflow until after DBOS is launched.

Example:

import os
from dbos import DBOS, DBOSConfig

# Configure and initialize DBOS
config: DBOSConfig = {
    "name": "dbos-starter",
    "system_database_url": os.environ.get("DBOS_SYSTEM_DATABASE_URL"),
}
DBOS(config=config)

@DBOS.step()
def step_one():
    print("Step one completed!")

@DBOS.step()
def step_two():
    print("Step two completed!")

@DBOS.workflow()
def dbos_workflow():
    step_one()
    step_two()

# Launch DBOS, then run a workflow.
if __name__ == "__main__":
    DBOS.launch()
    dbos_workflow()

destroy​

DBOS.destroy(
    workflow_completion_timeout_sec: int = 0,
    destroy_registry: bool = False
)

Destroy the DBOS singleton, terminating all active workflows and closing database connections. After this completes, the singleton can be re-initialized. Useful for testing.

Parameters:

  • workflow_completion_timeout_sec: Wait this many seconds for active workflows to complete before shutting down.
  • destroy_registry: Whether to destroy the global registry of decorated functions. If set to True, destroy will "un-register" all decorated functions. You probably want to leave this False.

reset_system_database​

DBOS.reset_system_database()

Destroy the DBOS system database, resetting DBOS's internal state in Postgres. Useful when testing a DBOS application to reset the internal state of DBOS between tests. For example, see its use in the testing tutorial. This is a destructive operation and should only be used in a test environment.