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 way provide both Time and TimeNano in the event. For the display of
the JSONMessage, use either, but prefer TimeNano Proving only TimeNano
would break Subscribers that are using the `Time` field, so both are set
for backwards compatibility.
The events logging uses nano formatting, but only provides a Unix()
time, therefor ordering may get lost in the output. Example:
```
2015-09-15T14:18:51.000000000-04:00 ee46febd64ac629f7de9cd8bf58582e6f263d97ff46896adc5b508db804682da: (from busybox) resize
2015-09-15T14:18:51.000000000-04:00 a78c9149b1c0474502a117efaa814541926c2ae6ec3c76607e1c931b84c3a44b: (from busybox) resize
```
By having a field just for Nano time, when set, the marshalling back to
`time.Unix(sec int64, nsec int64)` has zeros exactly where it needs to.
This does not break any existing use of jsonmessage.JSONMessage, but now
allows for use of `UnixNano()` and get event formatting that has
distinguishable order. Example:
```
2015-09-15T15:37:23.810295632-04:00 6adcf8ed9f5f5ec059a915466cd1cde86a18b4a085fc3af405e9cc9fecbbbbaf: (from busybox) resize
2015-09-15T15:37:23.810412202-04:00 6b7c5bfdc3f902096f5a91e628f21bd4b56e32590c5b4b97044aafc005ddcb0d: (from busybox) resize
```
Including tests for TimeNano and updated event API reference doc.
Signed-off-by: Vincent Batts <vbatts@redhat.com>
With go1.5's concurrency, the use of a goroutine in Log'ing events was
causing the resulting events to not be in order.
Signed-off-by: Vincent Batts <vbatts@redhat.com>
