Module Daml.Trigger¶

Typeclasses¶

Features possible in initialize, updateState, and rule.

queryContractId

: Template a => ContractId a -> m (Optional a)

Find the contract with the given id in the ACS, if present.

instance ActionTriggerAny (TriggerA s)

instance ActionTriggerAny TriggerInitializeA

instance ActionTriggerAny (TriggerUpdateA s)

class ActionTriggerAny m => ActionTriggerUpdate m where

Features possible in updateState and rule.

getCommandsInFlight

: m (Map CommandId [Command])

Retrieve command submissions made by this trigger that have not yet completed. If the trigger has restarted, it will not contain commands from before the restart; therefore, this should be treated as an optimization rather than an absolute authority on ledger state.

instance ActionTriggerUpdate (TriggerA s)

instance ActionTriggerUpdate (TriggerUpdateA s)

Data Types¶

data Trigger s

This is the type of your trigger. s is the user-defined state type which you can often leave at ().

Trigger

Field Type Description

initialize TriggerInitializeA s Initialize the user-defined state based on the ACS.

updateState Message -> TriggerUpdateA s () Update the user-defined state based on a transaction or completion message. It can manipulate the state with get, put, and modify, or query the ACS with query.

rule Party -> TriggerA s () The rule defines the main logic of your trigger. It can send commands to the ledger using emitCommands to change the ACS. The rule depends on the following arguments: * The party your trigger is running as. * The user-defined state. and can retrieve other data with functions in TriggerA: * The current state of the ACS. * The current time (UTC in wallclock mode, Unix epoch in static mode) * The commands in flight.

registeredTemplates RegisteredTemplates The templates the trigger will receive events for.

heartbeat Optional RelTime Send a heartbeat message at the given interval.

instance HasField “heartbeat” (Trigger s) (Optional RelTime)

instance HasField “initialize” (Trigger s) (TriggerInitializeA s)

instance HasField “registeredTemplates” (Trigger s) RegisteredTemplates

instance HasField “rule” (Trigger s) (Party -> TriggerA s ())

instance HasField “updateState” (Trigger s) (Message -> TriggerUpdateA s ())

data TriggerA s a

TriggerA is the type used in the rule of a Daml trigger. Its main feature is that you can call emitCommands to send commands to the ledger.

instance ActionTriggerAny (TriggerA s)

instance ActionTriggerUpdate (TriggerA s)

instance Functor (TriggerA s)

instance ActionState s (TriggerA s)

instance HasTime (TriggerA s)

instance Action (TriggerA s)

instance Applicative (TriggerA s)

instance HasField “rule” (Trigger s) (Party -> TriggerA s ())

instance HasField “runTriggerA” (TriggerA s a) (ACS -> TriggerRule (TriggerAState s) a)

data TriggerInitializeA a

TriggerInitializeA is the type used in the initialize of a Daml trigger. It can query, but not emit commands or update the state.

instance ActionTriggerAny TriggerInitializeA

instance Functor TriggerInitializeA

instance Action TriggerInitializeA

instance Applicative TriggerInitializeA

instance HasField “initialize” (Trigger s) (TriggerInitializeA s)

instance HasField “runTriggerInitializeA” (TriggerInitializeA a) (ACS -> a)

data TriggerUpdateA s a

TriggerUpdateA is the type used in the updateState of a Daml trigger. It has similar actions in common with TriggerA, but cannot use emitCommands or getTime.

instance ActionTriggerAny (TriggerUpdateA s)

instance ActionTriggerUpdate (TriggerUpdateA s)

instance Functor (TriggerUpdateA s)

instance ActionState s (TriggerUpdateA s)

instance Action (TriggerUpdateA s)

instance Applicative (TriggerUpdateA s)

instance HasField “runTriggerUpdateA” (TriggerUpdateA s a) ((Map CommandId [Command], ACS) -> State s a)

instance HasField “updateState” (Trigger s) (Message -> TriggerUpdateA s ())

Functions¶

query

: (Template a, ActionTriggerAny m) => m [(ContractId a, a)]

Extract the contracts of a given template from the ACS.

queryContractKey

: (Template a, HasKey a k, Eq k, ActionTriggerAny m, Functor m) => k -> m (Optional (ContractId a, a))

Find the contract with the given key in the ACS, if present.

emitCommands

: [Command] -> [AnyContractId] -> TriggerA s CommandId

Send a transaction consisting of the given commands to the ledger. The second argument can be used to mark a list of contract ids as pending. These contracts will automatically be filtered from getContracts until we either get the corresponding transaction event for this command or a failing completion.

dedupCreate

: (Eq t, Template t) => t -> TriggerA s ()

Create the template if it’s not already in the list of commands in flight (it will still be created if it is in the ACS).

Note that this will send the create as a single-command transaction. If you need to send multiple commands in one transaction, use emitCommands with createCmd and handle filtering yourself.

dedupCreateAndExercise

: (Eq t, Eq c, Template t, Choice t c r) => t -> c -> TriggerA s ()

Create the template and exercise a choice on it it’s not already in the list of commands in flight (it will still be created if it is in the ACS).

Note that this will send the create and exercise as a single-command transaction. If you need to send multiple commands in one transaction, use emitCommands with createAndExerciseCmd and handle filtering yourself.

dedupExercise

: (Eq c, Choice t c r) => ContractId t -> c -> TriggerA s ()

Exercise the choice on the given contract if it is not already in flight.

Note that this will send the exercise as a single-command transaction. If you need to send multiple commands in one transaction, use emitCommands with exerciseCmd and handle filtering yourself.

If you are calling a consuming choice, you might be better off by using emitCommands and adding the contract id to the pending set.

dedupExerciseByKey

: (Eq c, Eq k, Choice t c r, TemplateKey t k) => k -> c -> TriggerA s ()

Exercise the choice on the given contract if it is not already in flight.

Note that this will send the exercise as a single-command transaction. If you need to send multiple commands in one transaction, use emitCommands with exerciseCmd and handle filtering yourself.

runTrigger

: Trigger s -> Trigger (TriggerState s)

Transform the high-level trigger type into the one from Daml.Trigger.LowLevel.