EDMarketConnector/docs/Killswitches.md

Kill Switches

EDMarketConnector implements a Kill Switch system that allows us to disable features based on a version mask. Meaning that we can stop major bugs from affecting the services we support, at the expense of disabling that support.

Format

Killswitches are stored in a JSON file that is queried by EDMC on startup. The format is as follows:

Key	Type	Description
version	int	the version of the Kill Switch JSON file, always 1
last_updated	string	When last the kill switches were updated (for human use only)
kill_switches	array	The kill switches this file contains (expanded below)

The kill_switches array contains kill switch objects. Each contains the following fields:

Key	Type	Description
version	version spec	The version of EDMC these kill switches apply to (Must be valid semver spec)
kills	Dict[str, Dict[str, Any]]	The different keys to disable, and the reason for the disable

Each entry in kills contains a reason and additional_data field. reason is self explanatory, however additional_data can contain various things. They are outlaid below:

Key	Type	Description
redact_field	List[str]	A list of fields in the matching event to be redacted, if they exist.

An example follows:

{
    "version": 2,
    "last_updated": "3 July 2021",
    "kill_switches": [
        {
            "version": "1.0.0",
            "kills": {
                "plugins.eddn.send": {
                    "reason": "some reason",
                    "additional_data": {}
                }
            }
        }
    ]
}

Versions

Versions are checked using contains checks on semantic_version.SimpleSpec instances.

Plugin support

Plugins may use the killswitch system simply by hosting their own version of the killswitch file, and fetching it using killswitch.get_kill_switches(target='https://example.com/myplugin_killswitches.json'). The returned object can be used to query the kill switch set, see the docstrings for more information on specifying versions.

The version of the JSON file will be automatically upgraded if possible by the code KillSwitch code.

Currently supported killswitch strings

The current recognised (to EDMC and its internal plugins) killswitch strings are as follows:

Kill Switch	Description
plugins.eddn.send	Disables all use of the send method on EDDN (effectively disables EDDN updates)
plugins.(eddn|inara|edsm|eddb).journal	Disables all journal processing for EDDN/EDSM/INARA
plugins.(edsm|inara).worker	Disables the EDSM/INARA worker thread (effectively disables updates) (does not close thread)
plugins.(eddn|inara|edsm).journal.event.$eventname	Specific events to disable processing for

File location

The main killswitch file is kept in the releases branch on the EDMC github repo. The file should NEVER be committed to any other repos. In the case that the killswitch file is found in other repos, the one in releases should always be taken as correct regardless of others.