This PR adds a "request ID" to each event generated, the 'docker events'
stream now looks like this:
```
2015-09-10T15:02:50.000000000-07:00 [reqid: c01e3534ddca] de7c5d4ca927253cf4e978ee9c4545161e406e9b5a14617efb52c658b249174a: (from ubuntu) create
```
Note the `[reqID: c01e3534ddca]` part, that's new.
Each HTTP request will generate its own unique ID. So, if you do a
`docker build` you'll see a series of events all with the same reqID.
This allow for log processing tools to determine which events are all related
to the same http request.
I didn't propigate the context to all possible funcs in the daemon,
I decided to just do the ones that needed it in order to get the reqID
into the events. I'd like to have people review this direction first, and
if we're ok with it then I'll make sure we're consistent about when
we pass around the context - IOW, make sure that all funcs at the same level
have a context passed in even if they don't call the log funcs - this will
ensure we're consistent w/o passing it around for all calls unnecessarily.
ping @icecrime @calavera @crosbymichael
Signed-off-by: Doug Davis <dug@us.ibm.com>
This defines a 'context' object that is passed to each API handler.
Right now the context just has a unique 'requestID' for each API call.
The next steps would be:
- use this 'requestID' in our logging.
- determine the best way to format the logging to include this info.
In particular for log events that generate multiple entries in the log
we can use the requestID to help correlate the log entries.
Adding the requestID to the logging will be a challenge since it could mean
changing every single logrus.XXX() call to pass in the 'context' object.
But first step is to agree on a format, which we can discus in a subsequent
PR, but my initial thoughts are to add it right after the timestamp:
current format:
INFO[0039] POST /v1.21/build?buildargs=%7B%22foo%22%3A%22xxx%22%7D&cgroupparent=&cpuperiod=0&cpuquota=0&cpusetcpus=&cpusetmems=&cpushares=0&dockerfile=Dockerfile&memory=0&memswap=0&rm=1&t=&ulimits=null
proposed format:
INFO[0039-83dea1222191] POST /v1.21/build?buildargs=%7B%22foo%22%3A%22xxx%22%7D&cgroupparent=&cpuperiod=0&cpuquota=0&cpusetcpus=&cpusetmems=&cpushares=0&dockerfile=Dockerfile&memory=0&memswap=0&rm=1&t=&ulimits=null
Signed-off-by: Doug Davis <dug@us.ibm.com>
