Messages¶
These messages are dispatched by the core. We will also add the message handlers that are going to be used to process these messages.
| Message | Message Handler |
|---|---|
| NotifyInputJobDispatcherMessage | JobDispatcherMessageHandler::handleInputJobDispatcherMessage |
| ReDispatchMessage | JobDispatcherMessageHandler::handleReDispatchMessage |
| JobDispatcherMessage | JobDispatcherMessageHandler::handleNormalJobDispatcherMessage |
| ProgressFinishMessage | ProgressFinishMessageHandler |
| ProgressUpdateMessage | ProgressUpdateMessageHandler |
| AdvanceProcessStepMessage | AdvanceProcessStepMessageHandler |
| EmptyMessage | EmptyMessageHandler |
| HeartbeatMessage | HeartbeatMessageHandler |
| TimeSeriesCollectionMessage | TimeSeriesCollectionMessageHandler |
| NewUserMessage | NewUserMessageHandler |
| SendMail | SendMailHandler |
Overview¶
Job Dispatcher Messages¶
These messages belong to the job dispatcher and are responsible for managing and coordinating flow execution related messages.
The class JobDispatcherMessage a base class for NotifyInputJobDispatcherMessage, NotifyTransformationJobDispatcherMessage and
NotifyOutputJobDispatcherMessage. The corresponding handler (JobDispatcherMessageHandler::handleNormalJobDispatcherMessage)
will take care of all JobDispatcherMessage messages except for the NotifyInputJobDispatcherMessage.
NotifyInputJobDispatcherMessage¶
This message is used for dispatching start messages (of a standard process definition). Theoretically, we also
have NotifyTransformationJobDispatcherMessage and NotifyOutputJobDispatcherMessage, but they are not used.
The handler will create a process definition (consisting of a JobProgressDefinition and some SubsectionProgressDefinition
objects as children). Afterwards, the process definition will be initialized:
An instance of ModuleJobDispatchContext with a JDM ID, a flow execution ID and an environment ID is going to be
created.
Other Base Control Messages¶
The class BaseControlMessage has no inner meaning. It is meant to distinguish between Core Messages and
messages that extend ModuleJobDispatchContextAwareMessage which are the messages of the modules.
ReDispatchMessage¶
This message is used to re-dispatch a subsection. This happens if a subsection is split to different batches.
When the progress of a subsection is updated, it will be checked if there is a significant change in the percentage of
processed items. By default, based on the environment variable PROGRESS_DISPATCH_CONDITION_GRANULARITY (default: 10),
the percentage of processed items will be checked. If the difference is greater than the granularity, the subsection will
be re-dispatched. If so, a RedispatchMessage will be dispatched to trigger the redispatch logic in
JobDispatcherMappingHandler.
There is a rarely called second occurrence of the RedispatchMessage: If a parent subsection cannot be marked as done,
it will also be dispatched.
The handler will set a lock on the process step (i.e. the flow execution) to avoid duplicate processing. It will load a JDMs and already dispatched JDMs. It will also include the environments to distinguish between JDMs in different environments. Based on these 2 information, it will dispatch all messages that need to be re-dispatched.
AdvanceProcessStepMessage¶
This message is part of the (synchonous) Progress Update handling. This message will be triggered on a ProgressUpdatedEvent.
It will update the process step of the flow execution and call onLeave() of the current process step and onEnter()
of the next process step.
EmptyMessage¶
This message is used when no specific action is required. It is used in the Standard process definition.
Progress messages (deprecated)¶
Besides the job dispatcher messages, we have messages that are responsible for handling progress updates.
ProgressUpdateMessage, ProgressUpdatePreviewMessage and ProgressFinishMessage¶
These messages belong to the deprecated UpdatesProgress trait. They will be dispatched in the methods
updatesProgress and finishSubsection. They work asynchronously.
Other messages¶
HeartbeatMessage¶
This message is used by the heartbeat feature. See Heartbeat Command & Time series Command for more information.
TimeSeriesCollectionMessage¶
This message is used to handle time series data collection. See Heartbeat Command & Time series Command for more information.
NewUserMessage¶
This message is used to handle new user events.
SendMail¶
This message is used to handle sending emails.