Implement autonomous tasks

[pashagolub]

https://twitter.com/dsl4life/status/1250382007298899969

The idea is to mark some tasks as autonomous and execute them outside of the chain transaction scope.

Thanks @a-mckinley.

[a-mckinley]

Thanks for looking at this @pashagolub!

In the interim I went with a psql shell task to call the stored proc launched from by a 'SHELL::task_type which is working well, but it would be very useful to enable the SQL equivalent.

[pashagolub]

Please, try 118_context_support branch

$> pg_timetable -c worker01 -d timetable --upgrade
[2020-04-16 18:55:50.472 | worker01 | LOG   ]: Connection established...
[2020-04-16 18:55:50.516 | worker01 | LOG   ]: Proceeding as 'worker01' with client PID 6636
[2020-04-16 18:55:50.519 | worker01 | LOG   ]: Executing script: DDL
[2020-04-16 18:55:50.630 | worker01 | LOG   ]: Schema file executed: DDL
[2020-04-16 18:55:50.635 | worker01 | LOG   ]: Executing script: JSON Schema
[2020-04-16 18:55:50.638 | worker01 | LOG   ]: Schema file executed: JSON Schema
[2020-04-16 18:55:50.639 | worker01 | LOG   ]: Executing script: Built-in Tasks
[2020-04-16 18:55:50.651 | worker01 | LOG   ]: Schema file executed: Built-in Tasks
[2020-04-16 18:55:50.654 | worker01 | LOG   ]: Executing script: Job Functions
[2020-04-16 18:55:50.657 | worker01 | LOG   ]: Schema file executed: Job Functions
[2020-04-16 18:55:50.658 | worker01 | LOG   ]: Configuration schema created...
[2020-04-16 18:55:50.660 | worker01 | LOG   ]: Upgrading database...
[2020-04-16 18:55:50.667 | worker01 | USER  ]: Severity: NOTICE; Message: relation "migrations" already exists, skipping
[2020-04-16 18:55:50.705 | worker01 | LOG   ]: Checking for @reboot task chains...
[2020-04-16 18:55:50.717 | worker01 | LOG   ]: Number of chains to be executed: 0
[2020-04-16 18:55:50.719 | worker01 | LOG   ]: Checking for task chains...
[2020-04-16 18:55:50.721 | worker01 | LOG   ]: Number of chains to be executed: 0
[2020-04-16 18:55:50.722 | worker01 | LOG   ]: Checking for interval task chains...
[2020-04-16 18:55:50.724 | worker01 | LOG   ]: Number of active interval chains: 0
[2020-04-16 18:55:51.912 | worker01 | LOG   ]: Closing session

$> psql -U scheduler -d timetable -c "\i samples/autonomous.sql"
CREATE FUNCTION
CREATE FUNCTION
CREATE PROCEDURE
 chain_execution_config |      run_at
------------------------+-------------------
                      1 | @every 10 seconds
(1 row)


INSERT 0 1
$> pg_timetable -c worker01 -d timetable
[2020-04-16 18:55:55.849 | worker01 | LOG   ]: Connection established...
[2020-04-16 18:55:55.894 | worker01 | LOG   ]: Proceeding as 'worker01' with client PID 2892
[2020-04-16 18:55:56.065 | worker01 | LOG   ]: Checking for @reboot task chains...
[2020-04-16 18:55:56.067 | worker01 | LOG   ]: Number of chains to be executed: 0
[2020-04-16 18:55:56.076 | worker01 | LOG   ]: Checking for task chains...
[2020-04-16 18:55:56.083 | worker01 | LOG   ]: Number of chains to be executed: 0
[2020-04-16 18:55:56.084 | worker01 | LOG   ]: Checking for interval task chains...
[2020-04-16 18:55:56.086 | worker01 | LOG   ]: Number of active interval chains: 1
[2020-04-16 18:55:56.089 | worker01 | LOG   ]: Starting chain ID: 1; configuration ID: 1
[2020-04-16 18:55:56.103 | worker01 | USER  ]: Severity: NOTICE; Message: hi
[2020-04-16 18:55:56.248 | worker01 | USER  ]: Severity: NOTICE; Message: hi2
[2020-04-16 18:55:56.252 | worker01 | LOG   ]: Executed successfully chain ID: 1; configuration ID: 1
[2020-04-16 18:55:59.267 | worker01 | LOG   ]: Closing session