Log drivers may have an internal buffer size that can be accommodated
by the copier as it is more effective to buffer and send fewer though
larger messages that the log driver can consume.
This eliminates the need for Partial handling for drivers that do not
support the concept (ie: awslogs, which can only have events up to
service limits).
Signed-off-by: Jacob Vallejo <jakeev@amazon.com>
This reduces allocs and bytes used per log entry significantly as well
as some improvement to time per log operation.
Each log driver, however, must put messages back in the pool once they
are finished with the message.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
This allows the user to set a logging mode to "blocking" (default), or
"non-blocking", which uses the ring buffer as a proxy to the real log
driver.
This allows a container to never be blocked on stdio at the cost of
dropping log messages.
Introduces 2 new log-opts that works for all drivers, `log-mode` and
`log-size`. `log-mode` takes a value of "blocking", or "non-blocking"
I chose not to implement this as a bool since it is difficult to
determine if the mode was set to false vs just not set... especially
difficult when merging the default daemon config with the container config.
`log-size` takes a size string, e.g. `2MB`, which sets the max size
of the ring buffer. When the max size is reached, it will start
dropping log messages.
```
BenchmarkRingLoggerThroughputNoReceiver-8 2000000000 36.2 ns/op 856.35 MB/s 0 B/op 0 allocs/op
BenchmarkRingLoggerThroughputWithReceiverDelay0-8 300000000 156 ns/op 198.48 MB/s 32 B/op 0 allocs/op
BenchmarkRingLoggerThroughputConsumeDelay1-8 2000000000 36.1 ns/op 857.80 MB/s 0 B/op 0 allocs/op
BenchmarkRingLoggerThroughputConsumeDelay10-8 1000000000 36.2 ns/op 856.53 MB/s 0 B/op 0 allocs/op
BenchmarkRingLoggerThroughputConsumeDelay50-8 2000000000 34.7 ns/op 894.65 MB/s 0 B/op 0 allocs/op
BenchmarkRingLoggerThroughputConsumeDelay100-8 2000000000 35.1 ns/op 883.91 MB/s 0 B/op 0 allocs/op
BenchmarkRingLoggerThroughputConsumeDelay300-8 1000000000 35.9 ns/op 863.90 MB/s 0 B/op 0 allocs/op
BenchmarkRingLoggerThroughputConsumeDelay500-8 2000000000 35.8 ns/op 866.88 MB/s 0 B/op 0 allocs/op
```
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
This change updates how we handle long lines of output from the
container. The previous logic used a bufio reader to read entire lines
of output from the container through an intermediate BytesPipe, and that
allowed the container to cause dockerd to consume an unconstrained
amount of memory as it attempted to collect a whole line of output, by
outputting data without newlines.
To avoid that, we replace the bufio reader with our own buffering scheme
that handles log lines up to 16k in length, breaking up anything longer
than that into multiple chunks. If we can dispense with noting this
detail properly at the end of output, we can switch from using
ReadBytes() to using ReadLine() instead. We add a field ("Partial") to
the log message structure to flag when we pass data to the log driver
that did not end with a newline.
The Line member of Message structures that we pass to log drivers is now
a slice into data which can be overwritten between calls to the log
driver's Log() method, so drivers which batch up Messages before
processing them need to take additional care: we add a function
(logger.CopyMessage()) that can be used to create a deep copy of a
Message structure, and modify the awslogs driver to use it.
We update the jsonfile log driver to append a "\n" to the data that it
logs to disk only when the Partial flag is false (it previously did so
unconditionally), to make its "logs" output correctly reproduce the data
as we received it.
Likewise, we modify the journald log driver to add a data field with
value CONTAINER_PARTIAL_MESSAGE=true to entries when the Partial flag is
true, and update its "logs" reader to refrain from appending a "\n" to
the data that it retrieves if it does not see this field/value pair (it
also previously did this unconditionally).
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>
this prevents the copier from sending messages in the buffer to the closed
driver. If the copied took longer than the timeout to drain the buffer, this
aborts the copier read loop and return back so we can cleanup resources
properly.
Signed-off-by: Daniel Dao <dqminh@cloudflare.com>
When using a scanner, log lines over 64K will crash the Copier with
bufio.ErrTooLong. Subsequently, the ioutils.bufReader will grow without
bound as the logs are no longer being flushed to disk.
Signed-off-by: Burke Libbey <burke.libbey@shopify.com>
