Switch to a more formally-specified `kmsg`-style format for reading
the logs.
- update the spec in docs/logging.md
- check for bad names in pkg/memlogd with unit test
Signed-off-by: David Scott <dave.scott@docker.com>
- check writing to the log does not block
- check the log doesn't expand -- it should be finite
- check that client connections don't buffer arbitrary amounts of
data if the client is slow
Signed-off-by: David Scott <dave.scott@docker.com>
Previously we had a per-connection
bytes.Buffer // to be written to the connection
sync.Cond // to allow us to Wait for more data
This had the major disadvantage that the buffer was unbounded and so
a slow client could cause memory exhaustion in the server. This patch
replaces these with a single
chan *logEntry
which is naturally bounded and supports blocking read. We make write
non-blocking using select i.e. we drop messages rather than allocate
more space.
Signed-off-by: David Scott <dave.scott@docker.com>
This is an example external logging service which can be enabled by
adding it to the `init` section of the .yml, for example:
...
init:
- linuxkit/init:35866bb276c264a5f664bfac7456f4b9eeb87a4d
- linuxkit/runc:v0.4
- linuxkit/containerd:f2bc1bda1ab18146967fa1a149800aaf14bee81b
- linuxkit/ca-certificates:v0.4
- linuxkit/memlogd:cc035e5c9e4011ec1ba97a181a6689fc90965ce9
onboot:
...
Signed-off-by: David Scott <dave.scott@docker.com>
