This reverts commit 8daa593b07.
There are two undesirable aspects to the impl
- Only a bare wildcard is permitted
- The wildcard match is not performed in the order listed
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Since the introduction of log tuning capabilities to virt-admin by
@06b91785, this has been a much needed missing improvement on the way to
deprecate the global 'log_level'.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Right-aligning backslashes when defining macros or using complex
commands in Makefiles looks cute, but as soon as any changes is
required to the code you end up with either distractingly broken
alignment or unnecessarily big diffs where most of the changes
are just pushing all backslashes a few characters to one side.
Generated using
$ git grep -El '[[:blank:]][[:blank:]]\\$' | \
grep -E '*\.([chx]|am|mk)$$' | \
while read f; do \
sed -Ei 's/[[:blank:]]*[[:blank:]]\\$/ \\/g' "$f"; \
done
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Along with an empty string, it should also be possible for users to pass
NULL to the public APIs which in turn would trigger a routine(future
work) responsible for defining an appropriate default logging output
given the current circumstances.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
These helpers will manage the log destination defaults (fetch/set). The reason
for this is to stay consistent with the current daemon's behaviour with respect
to /etc/libvirt/<daemon>.conf file, since both assignment of an empty string
or not setting the log output variable at all trigger the daemon's decision on
the default log destination which depends on whether the daemon runs daemonized
or not.
This patch also changes the logic of the selection of the default
logging output compared to how it is done now. The main difference though is
that we should only really care if we're running daemonized or not, disregarding
the fact of (not) having a TTY completely (introduced by commit eba36a3878) as
that should be of the libvirtd's parent concern (what FD it will pass to it).
Before:
if (godaemon || !hasTTY):
if (journald):
use journald
if (godaemon):
if (privileged):
use SYSCONFIG/libvirtd.log
else:
use XDG_CONFIG_HOME/libvirtd.log
else:
use stderr
After:
if (godaemon):
if (journald):
use journald
else:
if (privileged):
use SYSCONFIG/libvirtd.log
else:
use XDG_CONFIG_HOME/libvirtd.log
else:
use stderr
Signed-off-by: Erik Skultety <eskultet@redhat.com>
This is mainly virLogAddOutputTo* which were replaced by virLogNewOutputTo* and
the previously poorly named ones virLogParseAndDefine* functions. All of these
are unnecessary now, since all the original callers were transparently switched
to the new model of separate parsing and defining logic.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
This method will eventually replace virLogParseAndDefineFilters which
currently does both parsing and defining.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
This API is the entry point to output modification of the logger. Currently,
everything is done by virLogParseAndDefineOutputs. Parsing and defining will be
split into two operations both handled by this method transparently.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Abstraction added over parsing a single filter. The method parses potentially a
set of logging filters, while adding each filter logging object to a
caller-provided array.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Another abstraction added on the top of parsing a single logging output. This
method takes and parses the whole set of outputs, adding each single output
that has already been parsed into a caller-provided array. If the user-supplied
string contained duplicate outputs, only the last occurrence is taken into
account (all the others are removed from the list), so we silently avoid
duplicate logs.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Same as for outputs, introduce a new method, that is basically the same as
virLogParseAndDefineFilter with the difference that it does not define the
filter. It rather returns a newly created object that needs to be inserted into
a list and then defined separately.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Introduce a method to parse an individual logging output. The difference
compared to the virLogParseAndDefineOutput is that this method does not define
the output, instead it makes use of the virLogNewOutputTo* methods introduced
in the previous patch and just returns the virLogOutput object that has to be
added to a list of object which then can be defined as a whole via
virLogDefineOutputs. The idea remains still the same - split parsing and
defining of the logging primitives (outputs, filters).
Additionally, since virLogNewOutputTo* methods are now finally used,
ATTRIBUTE_UNUSED can be successfully removed from the methods' definitions,
since that was just to avoid compiler complaints about unused static functions.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Prepare a method that only defines a set of filters. It takes a list of
filters, preferably created by virLogParseFilters. The original set of filters
is reset and replaced by the new user-provided set of filters.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Prepare a method that only defines a set of outputs. It takes a list of
outputs, preferably created by virLogParseOutputs. The original set of outputs
is reset and replaced by the new user-provided set of outputs.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Outputs are a bit trickier than filters, since the user(config)-specified
set of outputs can contain duplicates. That would lead to logging the same
message twice. For compatibility reasons, we cannot just error out and forbid
the daemon to start if we find duplicate outputs which do not make sense.
Instead, we could silently take into account only the last occurrence of the
duplicate output and remove all the previous ones, so that the logger will not
try to use them when it is looping over all of its registered outputs.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
In order to later split output parsing and output defining, introduce a new
function which will create a new virLogOutput object which the parser will
insert into a list with the list being eventually defined.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Right now virLogParse* functions are doing both parsing and defining of filters
and outputs which should be two separate operations. Since the naming is
apparently a bit poor this patch renames these functions to
virLogParseAndDefine* which eventually will be replaced by virLogSet*.
Additionally, virLogParse{Filter,Output} will be later (after the split) reused,
so that these functions do exactly what the their name suggests.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
This is just a convenience method for discarding a list of filters instead of
using a 'for' loop everywhere. It is safe to pass -1 as the number of elements
in the list as well as passing NULL as list reference.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Provide a separate method to free a logging filter object. This will come handy
once a method to create an individual logging filter object is introduced.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
This is just a convenience method for discarding a list of outputs instead of
using a 'for' loop everywhere. It is safe to pass -1 as the number of elements
in the list as well as passing NULL as list reference.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Provide a separate method to free a logging output object. This will come handy
once a method to create an individual logging output object is introduced.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Usage of this keyword in front of function declaration that is exported via a
header file is unnecessary, since internally, this has been the default for most
compilers for quite some time.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
In order to refactor the ugly virLogParseOutputs method, this is a neat way of
finding out whether the destination type (in the form of a string) user
provided is a valid one. As a bonus, if it turns out it is valid, we get the
actual enum which will later be passed to any of virLogAddOutput methods right
away.
It is often helpful to know which version of libvirt and QEMU
was present when a guest was first launched. Ensure this info
is written into the QEMU log file for each guest.
A earlier commit changed the global log buffer so that it only
records messages that are explicitly requested via the log
filters setting. This removes the performance burden, and
improves the signal/noise ratio for messages in the global
buffer. At the same time though, it is somewhat pointless, since
all the recorded log messages are already going to be sent to an
explicit log output like syslog, stderr or the journal. The
global log buffer is thus just duplicating this data on stderr
upon crash.
The log_buffer_size config parameter is left in the augeas
lens to prevent breakage for users on upgrade. It is however
completely ignored hereafter.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently the log filter strings are used in a string comparison
against the source filename each time log message is emitted.
If no log filters at all are set, there's obviously no string
comparison to be done. If any single log filter is set though,
this imposes a compute burden on every logging call even if logs
from the file in question are disabled. This string comparison
must also be done while the logging mutex is held, which has
implications for concurrency when multiple threads are emitting
log messages.
This changes the log filtering to be done based on the virLogSource
object name. The virLogSource struct is extended to contain
'serial' and 'priority' fields. Any time the global log filter
rules are changed a global serial number is incremented. When a
log message is emitted, the serial in the virLogSource instance
is compared with the global serial number. If out of date, then
the 'priority' field in the virLogSource instance is updated based
on the new filter rules. The 'priority' field is checked to see
whether the log message should be sent to the log outputs.
The comparisons of the 'serial' and 'priority' fields are done
with no locks held. So in the common case each logging call has
an overhead of 2 integer comparisons, with no locks held. Only
if the decision is made to forward the message to the log output,
or if the 'serial' value is out of date do locks need to be
acquired.
Technically the comparisons of the 'serial' and 'priority' fields
should be done with locks held, or using atomic operations. Both
of these options have a notable performance impact, however, and
since all writes a protected by a global mutex, it is believed
that worst case behaviour where the fields are read concurrently
with being written would merely result in an mistaken emission
or dropping of the log message in question. This is an acceptable
tradeoff for the performance benefit of avoiding locking.
As a quick benchmark, a demo program that registers 500 file
descriptors with the event loop (eg equiv of 500 QEMU monitor
commands), creates pending read I/O on every FD, and then runs
virEventRunDefaultImpl() took 4.6 seconds to do 51200 iterations.
After this optimization it only takes 3.3 seconds, with the log
APIs no longer being a relevant factor in the running time.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Any source file which calls the logging APIs now needs
to have a VIR_LOG_INIT("source.name") declaration at
the start of the file. This provides a static variable
of the virLogSource type.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
As part of the goal to get away from doing string matching on
filenames when deciding whether to emit a log message, turn
the virLogSource enum into a struct which contains a log
"name". There will eventually be one virLogSource instance
statically declared per source file. To minimise churn in this
commit though, a single global instance is used.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Convert the type of loop iterators named 'i', 'j', k',
'ii', 'jj', 'kk', to be 'size_t' instead of 'int' or
'unsigned int', also santizing 'ii', 'jj', 'kk' to use
the normal 'i', 'j', 'k' naming
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Call virLogVMessage instead of virLogMessage, since libudev
called us with a va_list object, not a list of arguments.
Honor message priority and strip the trailing newline.
https://bugzilla.redhat.com/show_bug.cgi?id=969152
When reading log output from QEMU/LXC we need to skip over any
libvirt log messages. Currently the QEMU driver checks for a
fixed string, but this is better done with a regex. Add a method
virLogProbablyLogMessage to do a regex check
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
