When told to read additional attributes from logs that we've sent to the
journal, pull out all of the non-trusted, non-user fields that we didn't
hard-code ourselves. More of PR#20726 and PR#21889.
When reading entries in the journald log reader, set the time zone on
timestamps that we read to UTC, so that we send UTC values to the client
instead of values that are local to whatever timezone dockerd happens to
be running in.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com> (github: nalind)
Log drivers are instantiated on a per-container basis, and passed the
container ID (along with other information) when they're initialized.
Drivers that care about that value are caching the value that they're
passed when they're initialized and using it in favor of the value
contained in Message structures that are passed to them, so the field in
Messages is unused, so we remove it.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>
Following a journal log almost always requires a descriptor to be
allocated. In cases where we're running out of descriptors, this means
we might get stuck while attempting to start following the journal, at a
point where it's too late to report it to the client and clean up
easily. The journal reading context will cache the value once it's
allocated, so here we move the check earlier, so that we can detect a
problem when we can still report it cleanly.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>
When we set up to start following a journal, if we get error results
from sd_journal_get_fd() or sd_journal_get_events() that prevent us from
following the journal, report the error instead of just mysteriously
failing.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com> (github: nalind)
When following a journal-based log, it was possible for the worker
goroutine, which reads the journal using the journal context and sends
entry data down the message channel, to be scheduled after the function
which started it had returned. This could create problems, since the
invoking function was closing the journal context object and message
channel before it returned, which could trigger use-after-free segfaults
and write-to-closed-channel panics in the worker goroutine.
Make the cleanup in the invoking function conditional so that it's only
done when we're not following the logs, and if we are, that it's left to
the worker goroutine to close them.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com> (github: nalind)
The journald log reader keeps a map of following readers so that it can
close them properly when the journald reader object itself is closed,
but it was possible for its worker goroutine to be scheduled so that the
worker attempted to remove a reader from the map before the reader had
been added to the map. This patch adds the item to the map before
starting the goroutine which is expected to eventually remove it.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com> (github: nalind)
When checking if we have the development files for libsystemd's journal
APIs, check for either 'libsystemd >= 209' and 'libsystemd-journal'. If
we find 'libsystemd', define the 'journald' tag, which defaults to using
the 'libsystemd.pc' file. If we find the older 'libsystemd-journal',
define both the 'journald' and 'journald_compat' tags, which causes the
'libsystemd-journal.pc' file to be consulted instead.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com> (github: nalind)
@noxiouz points out that we don't need to check for a nil result from
C.CString(), since an out-of-memory condition causes a runtime panic
instead.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com> (github: nalind)
If a logdriver doesn't register a callback function to validate log
options, it won't be usable. Fix the journald driver by adding a dummy
validator.
Teach the client and the daemon's "logs" logic that the server can also
supply "logs" data via the "journald" driver. Update documentation and
tests that depend on error messages.
Add support for reading log data from the systemd journal to the
journald log driver. The internal logic uses a goroutine to scan the
journal for matching entries after any specified cutoff time, formats
the messages from those entries as JSONLog messages, and stuffs the
results down a pipe whose reading end we hand back to the caller.
If we are missing any of the 'linux', 'cgo', or 'journald' build tags,
however, we don't implement a reader, so the 'logs' endpoint will still
return an error.
Make the necessary changes to the build setup to ensure that support for
reading container logs from the systemd journal is built.
Rename the Jmap member of the journald logdriver's struct to "vars" to
make it non-public, and to make it easier to tell that it's just there
to hold additional variable values that we want journald to record along
with log data that we're sending to it.
In the client, don't assume that we know which logdrivers the server
implements, and remove the check that looks at the server. It's
redundant because the server already knows, and the check also makes
using older clients with newer servers (which may have new logdrivers in
them) unnecessarily hard.
When we try to "logs" and have to report that the container's logdriver
doesn't support reading, send the error message through the
might-be-a-multiplexer so that clients which are expecting multiplexed
data will be able to properly display the error, instead of tripping
over the data and printing a less helpful "Unrecognized input header"
error.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com> (github: nalind)
