Used in conjuction with "on".
An external (or internal) agent may send a signal to an execution and the execution may have a "on" handler for it.
For example, imagine an execution with a sub part that checks every day at noon and closes cases that are over a certain date:
on 'close'
# close the case and then cancel main part...
cancel ref: 'main'
every 'day at noon'
signal 'close' if f.date_to < today
sequence tag: 'main'
# main part ...
The "every day at noon" sub part could be replaced by a signal emitted by a Ruby script triggered by a cron daemon, thus going from internal agent to external agent.
The Flor::Unit class has a #signal method handy for that:
flor_unit.signal('close', exid: execution_id)It accepts exid: and payload: messages.
The payload at the point of signalling is transmitted over to the receiving "on" or "trap".
set f.a 'A'
signal 'close'
set f.b 'B'
[ 0 1 2 ]
set f.c 'C'
passes { 'ret' => [ 0, 1, 2 ], 'a' => 'A', 'b' => 'B' } as payload
to any intercepting "on" or "trap" (c is not passed).
Externally, you can signal with a specific payload thanks to:
flor_unit.signal('close', exid: execution_id, payload: { 'f0' => 'zero' })If the exid of execution A is known in execution B, execution B can send a signal to A.
exid0 = @unit.launch(
%q{
trap signal: 'green' # block until receiving the 'green' signal
set f.done true
})
@unit.launch(
%q{
set f.a 'a'
signal exid: f.exid0 'green' # send 'green' signal to exid0
set f.b 'b'
},
payload: { 'exid0' => exid0 })