# Context

This module implements the Prefect context that is available when tasks run.

Tasks can import prefect and access prefect.context values that will be set when the task is run.

Context values can be accessed as attributes or as dictionary items.

Mutating the context from within a task is not recommended as it will not behave consistently across execution environments. Example:

import prefect

with prefect.context(dict(a=1, b=2)):
    print(prefect.context.a) # 1

print(prefect.context.get("a")) # undefined

Prefect provides various key / value pairs in context that are always available during task runs:

Variable	Description
`date`	an actual datetime object representing the current time
`today`	the current date formatted as `YYYY-MM-DD`
`today_nodash`	the current date formatted as `YYYYMMDD`
`yesterday`	yesterday's date formatted as `YYYY-MM-DD`
`yesterday_nodash`	yesterday's date formatted as `YYYYMMDD`
`tomorrow`	tomorrow's date formatted as `YYYY-MM-DD`
`tomorrow_nodash`	tomorrow's date formatted as `YYYYMMDD`
`logger`	the logger for the current task
`config`	the complete Prefect configuration object that is being used during this run
`flow_name`	the name of the current flow
`scheduled_start_time`	a datetime object representing the scheduled start time for the flow run; falls back to `now` for unscheduled runs
`parameters`	a dictionary of parameter values for the current flow run
`map_index`	the map index of the current task (if mapped, otherwise `None`)
`task_name`	the name of the current task
`task_full_name`	the name of the current task, including map index
`task_slug`	the slug of the current task
`task_tags`	the tags on the current task
`task_run_count`	the run count of the task run - typically only interesting for retrying tasks
`task_loop_count`	if the Task utilizes looping, the loop count of the task run
`task_run_name`	the run name of the current task (if provided, otherwise `None`)
`task_loop_result`	if the Task is looping, the current loop result

Prefect Cloud and Server supply some additional context variables:

Variable	Description
`flow_id`	the id of the current flow
`flow_run_id`	the id of the current flow run
`flow_run_version`	the state version of the current flow run
`flow_run_name`	the name of the current flow run
`task_id`	the id of the current task
`task_run_id`	the id of the current task run
`task_run_version`	the state version of the current task run
`resume`	boolean showing if the current task run was manually restarted

Users can also provide values to context at runtime. For more information, see the Context concept doc.

class

prefect.utilities.context.Context

(*args, **kwargs)[source]

A thread safe context store for Prefect data.

The Context is a DotDict subclass, and can be instantiated the same way.

Args:

*args (Any): arguments to provide to the DotDict constructor (e.g., an initial dictionary)
**kwargs (Any): any key / value pairs to initialize this context with

This documentation was auto-generated from commit bd9182e
on July 31, 2024 at 18:02 UTC