closes#317
we could fiddle with this, but we need to at least bound these. this
accomplishes that. 1m is picked since that's our default max log size for the
time being per call, it also takes a little time to generate that many bytes
through logs, typically (i.e. without trying to). I tested with 0, which
spiked the i/o rate on my machine because it's constantly deleting the json
log file. I also tested with 1k and it was similar (for a task that generated
about 1k in logs quickly) -- in testing, this halved my throughput, whereas
using 1m did not change the throughput at all. trying the 'none' driver and
'syslog' driver weren't great, 'none' turns off all stderr and 'syslog' blocks
every log line (boo). anyway, this option seems to have no affect on the
output we get in 'attach', which is what we really care about (i.e. docker is
not logically capping this, just swapping out the log file).
using 1m for this, e.g. if we have 500 hot containers on a machine we have
potentially half a gig of worthless logs laying around. we don't need the
docker logs laying around at all really, but short of writing a storage driver
ourselves there don't seem to be too many better options. open to idears, but
this is likely to hold us over for some time.
* push validate/defaults into datastore
we weren't setting a timestamp in route insert when we needed to create an app
there. that whole thing isn't atomic, but this fixes the timestamp issue.
closes#738
seems like we should do similar with the FireBeforeX stuff too.
* fix tests
* app name validation was buggy, an upper cased letter failed. now it doesn't.
uses unicode now.
* removes duplicate errors for datastore and models validation that were used
interchangably but weren't.
* pipe swapparoo each slot
previously, we made a pair of pipes for stdin and stdout for each container,
and then handed them out to each call (slot) to use. this meant that multiple
calls could have a handle on the same stdin pipe and stdout pipe to read/write
to/from from fn's perspective and could mix input/output and get garbage. this
also meant that each was blocked on the previous' reads.
now we make a new pipe every time we get a slot, and swap it out with the
previous ones. calls are no longer blocked from fn's perspective, and we don't
have to worry about timing out dispatch for any hot format. there is still the
issue that if a function does not finish reading the input from the previous
task, from its perspective, and reads the next call's it can error out the
second call. with fn deadline we provide the necessary tools to skirt this,
but without some additional coordination am not sure this is a closable hole
with our current protocols since terminating a previous calls input requires
some protocol specific bytes to go in (json in particular is tricky). anyway,
from fn's side fixing pipes was definitely a hole, but this client hole is
still hanging out. there was an attempt to send an io.EOF but the issue is
that will shut down docker's read on the stdin pipe (and the container). poop.
this adds a test for this behavior, and makes sure 2 containers don't get
launched.
this also closes the response writer header race a little, but not entirely, I
think there's still a chance that we read a full response from a function and
get a timeout while we're changing the headers. I guess we need a thread safe
header bucket, otherwise we have to rely on timings (racy). thinking on it.
* fix stats mu race
* Improve deadline handling in streaming protocols
* Move special headers handling down to the protocols
* Adding function format documentation for JSON changes
* Add tests for request url and method in JSON protocol
* Fix protocol missing fn-specific info
* Fix import
* Add panic for something that should never happen
* add spans to async
* clean up / add spans to agent
* there were a few methods which had multiple contexts which existed in the same
scope (this doesn't end well, usually), flattened those out.
* loop bound context cancels now rely on defer (also was brittle)
* runHot had a lot of ctx shuffling, flattened that.
* added some additional spans in certain paths for added granularity
* linked up the hot launcher / run hot / wait hot to _a_ root span, the first
2 are follows from spans, but at least we can see the source of these and also
can see containers launched over a hot launcher's lifetime
I left TODO around the FollowsFrom because OpenCensus doesn't, at least at the
moment, appear to have any idea of FollowsFrom and it was an extra OpenTracing
method (we have to get the span out, start a new span with the option, then
add it to the context... some shuffling required). anyway, was on the fence
about adding at least.
* resource waiters need to manage their own goroutine lifecycle
* if we get an impossible memory request, bail instead of infinite loop
* handle timeout slippery case
* still sucks, but hotLauncher doesn't leak anything. even the time.After timer goroutines
* simplify GetResourceToken
GetCall can guard against the impossible to allocate resource tasks entering
the system by erroring instead of doling them out. this makes GetResourceToken
logic more straightforward for callers, who now simply have the contract that
they won't ever get a token if they let tasks into the agent that can't run
(but GetCall guards this, and there's a test for it).
sorry, I was going to make this only do that, but when I went to fix up the
tests, my last patch went haywire so I fixed that too. this also at least
tries to simplify the hotLaunch loop, which will now no longer leak time.After
timers (which were long, and with signaller, they were many -- I got a stack
trace :) -- this breaks out the bottom half of the logic to check to see if we
need to launch into its own function, and handles the cleaning duties only in
the caller instead of in 2 different select statements. played with this a
bit, no doubt further cleaning could be done, but this _seems_ better.
* fix vet
* add units to exported method contract docs
* oops
we were using the httputil.DumpRequest when there is a perfectly good
req.Write method hanging out in the stdlib, that even does the chunked thing
that a few people ran into if they don't provide a content length:
https://golang.org/pkg/net/http/#Request.Write -- so we shouldn't run into
that issue again. I hit this in testing and it was not very fun to debug, so
added a test that repro'd it on master and fixes it here. of course, adding a
content length works too. tested this and it appears to work pretty well, also
cleaned up the control flow a little bit in http protocol.
*) Stopped using latency previous/current stats, this
was not working as expected. Fresh starts usually have
these stats zero for a long time, and initial samples
are high due to downloads, caches, etc.
*) New state to track: containers that are idle. In other
words, containers that have an unused token in the slot
queue.
*) Removed latency counts since these are not used in
container start decision anymore. Simplifies logs.
*) isNewContainerNeeded() simplified to use idle count
to estimate effective waiters. Removed speculative
latency based logic and progress check comparison.
In agent, waitHot() delayed signalling compansates
for these changes. If the estimation may fail, but
this should correct itself in the next 200 msec
signal.
* fn: resource and slot cancel and broadcast improvements
*) Context argument does not wake up the waiters correctly upon
cancellation/timeout.
*) Avoid unnecessary broadcasts in slot and resource.
* fn: limit scope of context in resource/slot calls in agent
since we were sending a signal before checking if a slot was available, even
in the case of serial calls locally I was seeing 2 containers launch. if we
only send a signal after first checking if a slot is available, this goes
away. 1 usec should not be too offensive of an additional wait, all things
considered here.
* fn: cancellations in WaitAsyncResource
Added go context with cancel to wait async resource. Although
today, the only case for cancellation is shutdown, this cleans
up agent shutdown a little bit.
* fn: locked broadcast to avoid missed wake-ups
* fn: removed ctx arg to WaitAsyncResource and startDequeuer
This is confusing and unnecessary.
