.. _acrnprobe_doc:
acrnprobe
#########
Description
***********
The ``acrnprobe`` is a tool to detect all critical events on the platform and
collect specific information for them. The collected information would be saved
as logs. The log path would be delivered to `telemetrics-client`_ as a record if
telemetrics-client exists on the system. In this case ``acrnprobe`` works as a
*probe* of telemetrics-client. If telemetrics-client doesn't exist on the
system, ``acrnprobe`` provides ``history_event`` (under ``/var/log/crashlog/``
by default) to manage the crash and events records on the platform instead of
``telem_journal``. But in this case, the records can't be delivered to the
backend.
Usage
*****
The ``acrnprobe`` is launched as a service at boot. Also, it provides some basic
options:
Specify a configuration file for ``acrnprobe``. If this option is unused,
``acrnprobe`` will use the configuration file located in CUSTOM CONFIGURATION
PATH or INSTALLATION PATH (see `CONFIGURATION FILES`_).
.. code-block:: none
$ acrnprobe -c [configuration_path]
To see the version of ``acrnprobe``.
.. code-block:: none
$ acrnprobe -V
Architecture
************
Terms
=====
- channel :
Channel represents a way of detecting the system's events. There are 3
channels:
+ oneshot: detect once while ``acrnprobe`` startup.
+ polling: run a detecting job with fixed time interval.
+ inotify: monitor the change of file or dir.
- trigger :
Essentially, trigger represents one section of content. It could be
a file's content, a directory's content, or a memory's content which can be
obtained. By monitoring it ``acrnprobe`` could detect certain events which
happened in the system.
- crash :
A subtype of event. It often corresponds to a crash of programs, system, or
hypervisor. ``acrnprobe`` detects it and reports it as ``CRASH``.
- info :
A subtype of event. ``acrnprobe`` detects it and reports it as ``INFO``.
- event queue :
There is a global queue to receive all events detected.
Generally, events are enqueued in channel, and dequeued in event handler.
- event handler :
Event handler is a thread to handle events detected by channel.
It's awakened by an enqueued event.
- sender :
The sender corresponds to an exit of event.
There are two senders:
+ Crashlog is responsible for collecting logs and saving it locally.
+ Telemd is responsible for sending log records to telemetrics client.
Description
===========
As a log collection mechanism to record critical events on the platform,
``acrnprobe`` provides these functions:
1. detect event
From experience, the occurrence of an system event is usually accompanied
by some effects. The effects could be a generated file, an error message in
kernel's log, or a system reboot. To get these effects, for some of them we
can monitor a directory, for other of them we might need to do a detection
in a time loop.
*So we implement the channel, which represents a common method of detection.*
2. analyze event and determine the event type
Generally, a specific effect correspond to a particular type of events.
However, it is the icing on the cake for analyzing the detailed event types
according to some phenomena. *Crash reclassify is implemented for this
purpose.*
3. collect information for detected events
This is for debug purpose. Events without information are meaningless,
and developers need to use this information to improve their system. *Sender
crashlog is implemented for this purpose.*
4. archive these information as logs, and generate records
There must be a central place to tell user what happened in system.
*Sender telemd is implemented for this purpose.*
Diagram
=======
::
+---------------------------------------------+
| channel: |oneshot| |polling| |inotify| |
+--------------------------------------+------+
|
+---------------------+ +-----+ |
| event queue +<---+event+<----+
+-+-------------------+ +-----+
|
v
+-+---------------------------------------------------------------------------+
| event handler: |
| |
| event handler will handle internal event |
| +----------+ +------------+ |
| |heart beat+--->+fed watchdog| |
| +----------+ +------------+ |
| |
| call sender for other types |
| +--------+ +----------------+ +------------+ +------------------+ |
| |crashlog+-->+crash reclassify+-->+collect logs+-->+generate crashfile| |
| +--------+ +----------------+ +------------+ +------------------+ |
| |
| +------+ +------------------+ |
| |telemd+--->+telemetrics client| |
| +------+ +------------------+ |
+-----------------------------------------------------------------------------+
Source files
************
- main.c
Entry of ``acrnprobe``.
- channel.c
The implementation of *channel* (see `Terms`_).
- crash_reclassify.c
Analyzing the detailed types for crash event.
- probeutils.c
Provide some utils ``acrnprobe`` needs.
- event_queue.c
The implementation of *event queue* (see `Terms`_).
- event_handler.c
The implementation of *event handler* (see `Terms`_).
- history.c
There is a history_event file to manage all logs that ``acrnprobe`` archived.
"history.c" provides the interfaces to modify the file in fixed format.
- load_conf.c
Parse and load the configuration file.
- property.c
The ``acrnprobe`` needs to know some HW/SW properties, such as board version,
build version. These properties are managed centrally in this file.
- sender.c
The implementation of *sender* (see `Terms`_).
- startupreason.c
This file provides the function to get system reboot reason from kernel
command line.
- android_events.c
Sync events detected by android crashlog.
- loop.c
This file provides interfaces to read from image.
Configuration files
*******************
* ``/usr/share/defaults/telemetrics/acrnprobe.xml``
If no custom configuration file is found, ``acrnprobe`` uses the settings in
this file.
* ``/etc/acrnprobe.xml``
Custom configuration file that ``acrnprobe`` reads.
For details about configuration file, please refer to :ref:`acrnprobe-conf`.
.. _`telemetrics-client`: https://github.com/clearlinux/telemetrics-client
9368373fd9