Hello,
I am currently looking at:
MYNEWT-262 <https://issues.apache.org/jira/browse/MYNEWT-262> Log module needs
split in logging and reporting
My understanding of the problem is as follows:
- We do not have a way to re-register a log(Change handlers of modules)
currently. The application should be able to override handlers for different
logs.
Solution is to do the following:
- Make changes to the log_register() function to take LOG_MODULE_X as an
argument. This module ID is present as a field in the log structure and can be
used anytime an entry is logged in the specific log. There was a disconnect
earlier as the log itself did not quite have a module ID of it’s own. If we
want to be able to filter logs the module ID needs to be used as a filtering
criteria to pick the right log node from the queue.
- Also, various MACROs such as LOG_INFO, LOG_DEBUG, LOG_WARN, etc require the
module ID to be passed as an argument which is not necessary as the log
structure itself contains the module ID.
- The log_append() function would not need the module ID to be passed as an
argument to it.
- Add a function log_set_handler(handler) to set handlers for all the modules
to the same one.
- When newtmgr requests to read all the logs using “logs show” command, the
response would contain a module ID as well. If the response does not contain
any entries, no response would be sent for that log. Module ID also helps in
filtering the log entries while sending the response.
JSON Response:
{
"rc": 0,
"logs": [{
"name": "log",
"module": 0,
"type": 1,
"entries": [{
"msg": "GPIO toggle from 1 to 0",
"ts": 1007000,
"level": 2,
"index": 1
}, {
"msg": "GPIO toggle from 0 to 1",
"ts": 2015000,
"level": 2,
"index": 2
}, {
"msg": "GPIO toggle from 1 to 0",
"ts": 3019000,
"level": 2,
"index": 3
}, {
"msg": "GPIO toggle from 0 to 1",
"ts": 4024000,
"level": 2,
"index": 4
}]
}]
}
When the log_set_handler() function is called in the app, it makes all the
function pointers if any nodes exist in the TAILQ to point to the same log
handlers. One problem with this approach is that since the log_set_handler()
function needs to be called after all the modules are initialized, logging to
the same log during initialization is not possible as the logs are not created
at that point.
Ways to solve this:
1. Passing the log handler as an argument to all the init functions which I
don’t like personally as it is not too clean.
2. Having a global default log handler which gets set by calling
log_set_handler() which would take precedence over other logs as log_register()
would also look at this default handler and if the default handler is present,
the log infrastructure decides to use that instead of whats specified in the
modules. As a result everything that gets logged would go to the log defined by
the app including initialization logs.
Thoughts ?
Regards,
Vipul Rahane
