The jsonlog logger currently allows specifying envs and labels that
should be propagated to the log message, however there has been no way
to read that back.
This adds a new API option to enable inserting these attrs back to the
log reader.
With timestamps, this looks like so:
```
92016-04-08T15:28:09.835913720Z foo=bar,hello=world hello
```
The extra attrs are comma separated before the log message but after
timestamps.
Without timestaps it looks like so:
```
foo=bar,hello=world hello
```
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Added --since argument to `docker logs` command. Accept unix
timestamps and shows logs only created after the specified date.
Default value is 0 and passing default value or not specifying
the value in the request causes parameter to be ignored (behavior
prior to this change).
Signed-off-by: Ahmet Alp Balkan <ahmetalpbalkan@gmail.com>
