Svc::ActiveLogger Component
1. Introduction
The Svc::ActiveLogger component processes events from other components. The events are put in packets and sent to an
external component like the ground interface. The component provides event filtering capability such that events may
be turned off via ID or severity.
2. Requirements
The requirements for Svc::ActiveLogger are as follows:
| Requirement | Description | Verification Method |
|---|---|---|
| AL-001 | The Svc::ActiveLogger component shall receive events and compose them into downlink packets. |
Inspection; Unit Test |
| AL-002 | The Svc::ActiveLogger component shall have commands to filter events based on event severity. |
Unit Test |
| AL-003 | The Svc::ActiveLogger component shall have commands to filter events based on the event ID. |
Unit Test |
| AL-004 | The Svc::ActiveLogger component shall call fatalOut port when FATAL is received |
Inspection; Unit Test |
3. Design
3.1 Context
3.1.1 Component Diagram
The Svc::ActiveLogger component has the following component diagram:
3.1.2 Ports
The Svc::ActiveLogger component uses the following port types:
| Port Data Type | Name | Direction | Kind | Usage |
|---|---|---|---|---|
Fw::Log |
LogRecv | Input | Synchronous | Receive events from components |
Fw::Com |
PktSend | Output | n/a | Send event packets to external user |
Svc::FatalEvent |
FatalAnnounce | Output | n/a | Send FATAL event (to health) |
3.2 Functional Description
The Svc::ActiveLogger component provides an event logging function for the software. The framework autocoder allows
developers to specify a set of events in the component XML
(see Events. For these components, the
autocoder will add an Fw::Log output port to send events in serialized form. The ActiveLogger receives these port
calls and provides commands to filter these events. The filtered events are sent to other components such as the ground
interface.
Note: the Event ID value 0 is reserved for the logger.
Should a FATAL severity event arrive, it is announced using a FATAL out port allow the system to respond when a FATAL event is seen.
3.2.1 Filtering
The Svc::ActiveLogger LogRecv input port handler filters events to lessen the load on the downstream components. The
filters can be set by severity and ID. By default, the DIAGNOSTIC events are filtered out since the number of DIAGNOSTIC
events can be quite high. All defaults can be globally configured in config/ActiveLoggerImplCfg.hpp. Filters are
modified at runtime by the SET_EVENT_FILTER command.
The component also allows filtering events by event ID. There is a configuration parameter that sets the number of IDs
that can be filtered. This allows operators to mute a particular event that might be flooding the downstream components.
These filters are modified at runtime by the SET_ID_FILTER command.
FATAL events are never filtered, so they can be caught and broadcast to the system. Outgoing events are converted into
the F´ ground format and sent out using the PktSend port.
3.2.2 Fatal Announce
When the ActiveLogger component receives a FATAL event, it calls the FatalAnnounce port. Another component that
handles the system response to FATALs (such as resetting the system) can connect to this port to be informed when a
FATAL has occurred.
3.3 Scenarios
3.3.1 Receive Events
The Svc::ActiveLogger component accepts events from other components.
3.4 State
Svc::ActiveLogger has no state machines, but stores the state of the event severity and event ID filters.
3.5 Algorithms
Svc::ActiveLogger has no significant algorithms.
4. Dictionaries
TBD
5. Module Checklists
| Checklist |
|---|
| Design |
| Code |
| Unit Test |
6. Unit Testing
To see unit test coverage run fprime-util check --coverage
7. Change Log
| Date | Description |
|---|---|
| 6/25/2015 | Design review edits |
| 7/22/2015 | Design review actions |
| 9/7/2015 | Unit Test updates |
| 10/28/2015 | Added FATAL announce port |
| 12/1/2020 | Removed event buffers and post-filter |