Server extension callbacks

This section compares the function syntax of a server extension to the equivalent logic in a trigger.

Example usage of a server extension compared to a trigger

Triggers:
name form-in change script.pl

function InstanceConfigEvents()
    return { ["form-in"] = "change" }
end
function FormIn()
    ...
end

Triggers:
... change-submit //a/b/c/... script.sh
... change-submit //a/c/d/... script.sh
... change-submit -//a/d/e/... script.sh

function InstanceConfigEvents()
    return { ["change-submit"] = { "//a/b/c/...", "//a/c/d/...", "-//a/d/e/..." } }
end
function ChangeSubmit()
    ...
end

Event Callbacks

The following table lists the Helix Core events that can cause a server extension to run. Instead of managing a trigger table, the server extensions use InstanceConfigFields() function to bind themselves to events.

In the following table,

• a form type can be: "branch", "change", "client", "depot", "group", "job", "label", "protect", "server", "spec", "stream", "triggers", "typemap", "user"

• server IDs might be similar to “build-123”, "commit1"

• a “pre-user-” and “post-user-” example might be similar to {“pre-user-obliterate”, “post-user-add”}

PressurePause callback

To prioritize certain commands, consider using the PressurePause Extension hook callback. PressurePause can call the SetPauseState() function to tell the server to keep pausing the command, unpause the command, or let the server determine whether to pause or unpause the command. Only one PressurePause Extension is allowed.

See also these Trigger script variables in Helix Core Server Administrator Guide:

%sessionsPaused% -- Number of paused client commands.

%pauseRateCPU% -- Percentage of commands blocked for CPU.

%pauseRateMem% -- Percentage of commands blocked for memory.

%pressureMem% -- low/medium/high memory pressure.

%pressureCPU% -- high CPU pressure.