* 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.
this was getting bloated with various contexts and spans and stats
administrivia that obfuscated what was going on a lot. this makes some helper
methods to shove most of that stuff into, and simplifies the context handling
around getting a slot by moving it inside of slot acquisition code. also
removed most uses of `call.Model()` -- I'll kill this thing some day, but if a
reason is needed, then the overhead of dynamic dispatch is unnecessary, we're
inside of the implementee for the agent, we don't want to use the interface
methods inside of that.
*) revert executor wait queue size comparison. This is too
aggresive and with stall check below, now unnecessary.
*) new container logic now checks if stats are constant, if
this is the case, then we assume the system is stalled (eg
running functions that take long time), this means we need
to make progress and spin up a new container.
* Change basic stats to use opentracing rather than Prometheus API directly
* Just ran gofmt
* Extract opentracing access for metrics to common/metrics.go
* Replace quotes strings with constants where possible
Latency stats are not always read-time updated and
if calls are stuck in waiting state, isNewContainerNeeded()
needs to be a bit more aggresive if the wait queue grows.
possible breakages:
* `FN_HEADER` on cold are no longer `s/-/_/` -- this is so that cold functions
can rebuild the headers as they were when they came in on the request (fdks,
specifically), there's no guarantee that a reversal `s/_/-/` is the original
header on the request.
* app and route config no longer `s/-/_/` -- it seemed really weird to rewrite
the users config vars on these. should just pass them exactly as is to env.
* headers no longer contain the environment vars (previously, base config; app
config, route config, `FN_PATH`, etc.), these are still available in the
environment.
this gets rid of a lot of the code around headers, specifically the stuff that
shoved everything into headers when constructing a call to begin with. now we
just store the headers separately and add a few things, like FN_CALL_ID to
them, and build a separate 'config' now to store on the call. I thought
'config' was more aptly named, 'env' was confusing, though now 'config' is
exactly what 'base_vars' was, which is only the things being put into the env.
we weren't storing this field in the db, this doesn't break unless there are
messages in a queue from another version, anyway, don't think we're there and
don't expect any breakage for anybody with field name changes.
this makes the configuration stuff pretty straight forward, there's just two
separate buckets of things, and cold just needs to mash them together into the
env, and otherwise hot containers just need to put 'config' in the env, and then
hot format can shove 'headers' in however they'd like. this seems better than
my last idea about making this easier but worse (RIP).
this means:
* headers no longer contain all vars, the set of base vars can only be found
in the environment.
* headers is only the headers from request + call_id, deadline, method, url
* for cold, we simply add the headers to the environment, prepending
`FN_HEADER_` to them, BUT NOT upper casing or `s/-/_/`
* fixes issue where async hot functions would end up with `Fn_header_`
prefixed headers
* removes idea of 'base' vars and 'env'. this was a strange concept. now we just have
'config' which was base vars, and headers, which was base_env+headers; i.e.
they are disjoint now.
* casing for all headers will lean to be `My-Header` style, which should help
with consistency. notable exceptions for cold only are FN_CALL_ID, FN_METHOD,
and FN_REQUEST_URL -- this is simply to avoid breakage, in either hot format
they appear as `Fn_call_id` still.
* removes FN_PARAM stuff
* updated doc with behavior
weird things left:
`Fn_call_id` e.g. isn't a correctly formatted http header, it should likely be
`Fn-Call-Id` but I wanted to live to fight another day on this one, it would
add some breakage.
examples to be posted of each format below
closes#329
Since by policy we require timeout/2 remaining time
before we can execute the request, we should also
bound the slot wait time by timeout/2 to avoid
waiting for full timeout in slot wait phase.
*) Updated fn-test-utils to latest fdk-go
*) Added hot-json to runner tests
*) Removed anon function in FromRequest which had
a side effect to set req.URL.Host. This is now more
explicit and eliminates some corresponding logic in
protocol http.
*) in gin, http request RequestURI is not set, removed
code that references this. (use Call.URL instead)
*) during shutdown, errors should be 503
*) new inactivity time out for hot queue, we previously kept hot queues in memory forever.
*) each hot queue now has a hot launcher to monitor and launch hot containers
*) consumers now create a consumer channel with startDequeuer() that can be cancelled via context
*) consumers now ping (signal) hot launcher every 200 msecs until they get a slot
*) tests for slot queue & mgr
* route updated_at
* add app created at, fix some route updated_at bugs
* add app updated_at
TODO need to add tests through front end
TODO for validation we don't really want to use the validate wrapper since
it's a programmer error and not a user error, hopefully tests block this.
* add tests for timestamps to exist / change on apps&routes
* route equals at done, fix tests wit dis
* fix up the equals sugar
* add swagger
* fix rebase
* precisely allocate maps in clone
* vetted
* meh
* fix api tests
* fn: remove 100 msec sleep for hot containers
*) moved slot management to its own file
*) slots are now implemented with LIFO semantics, this is important since we do
not want to round robin hot containers. Idle hot containers should timeout properly.
*) each slot queue now stores a few basic stats such as avg time a call spent in a given
state and number of running/launching containers, number of waiting calls in those states.
*) first metrics in these basic stats are discarded to avoid initial docker pull/start spikes.
*) agent now records/updates slot queue state and how much time a call stayed in that state.
*) waitHotSlot() replaces the previous wait 100 msec logic where it sends a msg to
hot slot go routine launchHot() and waits for a slot
*) launchHot() is now a go routine for tracking containers in hot slots, it determines
if a new containers is needed based on slot queue stats.
* fn: for async hot requests ensure/fix content-length/type
* fn: added tests for FromModel for content type/length
* fn: restrict the content-length fix to async in FromModel()
* fix configuration of agent and server to be future proof and plumb in the hybrid client agent
* fixes up the tests, turns off /r/ on api nodes
* fix up defaults for runner nodes
* shove the runner async push code down into agent land to use client
* plumb up async-age
* return full call from async dequeue endpoint, since we're storing a whole
call in the MQ we don't need to worry about caching of app/route [for now]
* fast safe shutdown of dequeue looper in runner / tidying of agent
* nice errors for path not found against /r/, /v1/ or other path not found
* removed some stale TODO in agent
* mq backends are only loud mouths in debug mode now
* update tests
* Add caching to hybrid client
* Fix HTTP error handling in hybrid client.
The type switch was on the value rather than a pointer.
* Gofmt.
* Better caching with a nice caching wrapper
* Remove datastore cache which is now unused
* Don't need to manually wrap interface methods
* Go fmt
* so it begins
* add clarification to /dequeue, change response to list to future proof
* Specify that runner endpoints are also under /v1
* Add a flag to choose operation mode (node type).
This is specified using the `FN_NODE_TYPE` environment variable. The
default is the existing behaviour, where the server supports all
operations (full API plus asynchronous and synchronous runners).
The additional modes are:
* API - the full API is available, but no functions are executed by the
node. Async calls are placed into a message queue, and synchronous
calls are not supported (invoking them results in an API error).
* Runner - only the invocation/route API is present. Asynchronous and
synchronous invocation requests are supported, but asynchronous
requests are placed onto the message queue, so might be handled by
another runner.
* Add agent type and checks on Submit
* Sketch of a factored out data access abstraction for api/runner agents
* Fix tests, adding node/agent types to constructors
* Add tests for full, API, and runner server modes.
* Added atomic UpdateCall to datastore
* adds in server side endpoints
* Made ServerNodeType public because tests use it
* Made ServerNodeType public because tests use it
* fix test build
* add hybrid runner client
pretty simple go api client that covers surface area needed for hybrid,
returning structs from models that the agent can use directly. not exactly
sure where to put this, so put it in `/clients/hybrid` but maybe we should
make `/api/runner/client` or something and shove it in there. want to get
integration tests set up and use the real endpoints next and then wrap this up
in the DataAccessLayer stuff.
* gracefully handles errors from fn
* handles backoff & retry on 500s
* will add to existing spans for debuggo action
* minor fixes
* meh
* squash# This is a combination of 10 commits2
fn: get available memory related changes
*) getAvailableMemory() improvements
*) early fail if requested memory too large to meet
*) tracking async and sync pools individually. Sync pool
is reserved for sync jobs only, while async pool can be
used by all jobs.
*) head room estimation for available memory in Linux.
* add error to call model
closes#331
previously, for async this error was being masked completely even if it was
something useful like the image not existing. for sync, the error was returned
in the http request but now it's also being stored. this error itself can
cover a lot of landscape, it could be an error in getting a slot, pulling an
image, running a container, among other things. anyway, no longer being
masked. we can likely improve it in certain cases we run into in the future,
but it's open ended at the moment and not being masked like some errors in
sync http request returns (503 non-models.APIError) for now.
* tucks in callTrigger stuff to keep api clean
* adds swagger
* adds migration
* adds tests for datastore and agent to ensure behavior
* pull images before tests are ran
* gofmt migrations file
* add per call stats field as histogram
this will add a histogram of up to 240 data points of call data, produced
every second, stored at the end of a call invocation in the db. the same
metrics are also still shipped to prometheus (prometheus has the
not-potentially-reduced version). for the API reference, see the updates to
the swagger spec, this is just added onto the get call endpoint.
this does not add any extra db calls and the field for stats in call is a json
blob, which is easily modified to add / omit future fields. this is just
tacked on to the call we're making to InsertCall, and expect this to add very
little overhead; we are bounding the set to be relatively small, planning to
clean out the db of calls periodically, functions will generally be short, and
the same code used at a previous firm did not cause a notable db size increase
with production workload that is worse, wrt histogram size (I checked). the
code changes are really small aside from changing to strfmt.DateTime,
adding a migration and implementing sql.Valuer; needed to slightly modify the
swap function so that we can safely read `call.Stats` field to upload at end.
with the full histogram in hand, we can compute max/min/average/median/growth
rate/bernoulli distributions/whatever very easily in a UI or tooling. in
particular, this data is easily chartable [for a UI], which is beneficial.
* adds swagger spec of api update to calls endpoint
* adds migration for call.stats field
* adds call.stats field to sql queries
* change swapping of hot logger to exec, so we know that call.Stats is no
longer being modified after `exec` [in call.End]
* throws out docker stats between function invocations in hot functions (no
call to store them on, we could change this later for debug; they're in prom)
* tested in tests and API
closes#19
* add format of ints to swag
