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agent.go
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agent.go
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package agent
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"net"
"net/http"
"strings"
"sync"
"time"
"path/filepath"
"github.com/fnproject/fn/api/agent/drivers"
"github.com/fnproject/fn/api/common"
"github.com/fnproject/fn/api/id"
"github.com/fnproject/fn/api/models"
"github.com/fnproject/fn/fnext"
"github.com/fsnotify/fsnotify"
docker "github.com/fsouza/go-dockerclient"
"github.com/sirupsen/logrus"
"go.opencensus.io/stats"
"go.opencensus.io/trace"
"os"
)
const (
pauseTimeout = 5 * time.Second // docker pause/unpause
)
// TODO we should prob store async calls in db immediately since we're returning id (will 404 until post-execution)
// TODO async calls need to add route.Headers as well
// TODO handle timeouts / no response in sync & async (sync is json+503 atm, not 504, async is empty log+status)
// see also: server/runner.go wrapping the response writer there, but need to handle async too (push down?)
// TODO storing logs / call can push call over the timeout
// TODO async is still broken, but way less so. we need to modify mq semantics
// to be much more robust. now we're at least running it if we delete the msg,
// but we may never store info about that execution so still broked (if fn
// dies). need coordination w/ db.
// TODO if async would store requests (or interchange format) it would be slick, but
// if we're going to store full calls in db maybe we should only queue pointers to ids?
// TODO examine cases where hot can't start a container and the user would never see an error
// about why that may be so (say, whatever it is takes longer than the timeout, e.g.)
// TODO if an image is not found or similar issues in getting a slot, then async should probably
// mark the call as errored rather than forever trying & failing to run it
// TODO it would be really nice if we made the ramToken wrap the driver cookie (less brittle,
// if those leak the container leaks too...) -- not the allocation, but the token.Close and cookie.Close
// TODO if machine is out of ram, just timeout immediately / wait for hot slot? (discuss policy)
// Agent exposes an api to create calls from various parameters and then submit
// those calls, it also exposes a 'safe' shutdown mechanism via its Close method.
// Agent has a few roles:
// * manage the memory pool for a given server
// * manage the container lifecycle for calls
// * execute calls against containers
// * invoke Start and End for each call appropriately
// * check the mq for any async calls, and submit them
//
// Overview:
// Upon submission of a call, Agent will start the call's timeout timer
// immediately. If the call is hot, Agent will attempt to find an active hot
// container for that route, and if necessary launch another container. calls
// will be able to read/write directly from/to a socket in the container. If
// it's necessary to launch a container, first an attempt will be made to try
// to reserve the ram required while waiting for any hot 'slot' to become
// available [if applicable]. If there is an error launching the container, an
// error will be returned provided the call has not yet timed out or found
// another hot 'slot' to execute in [if applicable]. call.Start will be called
// immediately before sending any input to a container. call.End will be called
// regardless of the timeout timer's status if the call was executed, and that
// error returned may be returned from Submit.
type Agent interface {
// GetCall will return a Call that is executable by the Agent, which
// can be built via various CallOpt's provided to the method.
GetCall(...CallOpt) (Call, error)
// Submit will attempt to execute a call locally, a Call may store information
// about itself in its Start and End methods, which will be called in Submit
// immediately before and after the Call is executed, respectively. An error
// will be returned if there is an issue executing the call or the error
// may be from the call's execution itself (if, say, the container dies,
// or the call times out).
Submit(Call) error
// Close will wait for any outstanding calls to complete and then exit.
// Closing the agent will invoke Close on the underlying DataAccess.
// Close is not safe to be called from multiple threads.
io.Closer
AddCallListener(fnext.CallListener)
}
type agent struct {
cfg Config
da CallHandler
callListeners []fnext.CallListener
driver drivers.Driver
slotMgr *slotQueueMgr
evictor Evictor
// track usage
resources ResourceTracker
// used to track running calls / safe shutdown
shutWg *common.WaitGroup
shutonce sync.Once
callOverrider CallOverrider
// deferred actions to call at end of initialisation
onStartup []func()
}
// Option configures an agent at startup
type Option func(*agent) error
// RegistryToken is a reserved call extensions key to pass registry token
/* #nosec */
const RegistryToken = "FN_REGISTRY_TOKEN"
// New creates an Agent that executes functions locally as Docker containers.
func New(da CallHandler, options ...Option) Agent {
cfg, err := NewConfig()
if err != nil {
logrus.WithError(err).Fatalf("error in agent config cfg=%+v", cfg)
}
a := &agent{
cfg: *cfg,
}
a.shutWg = common.NewWaitGroup()
a.da = da
a.slotMgr = NewSlotQueueMgr()
a.evictor = NewEvictor()
// Allow overriding config
for _, option := range options {
err = option(a)
if err != nil {
logrus.WithError(err).Fatal("error in agent options")
}
}
logrus.Infof("agent starting cfg=%+v", a.cfg)
if a.driver == nil {
d, err := NewDockerDriver(&a.cfg)
if err != nil {
logrus.WithError(err).Fatal("failed to create docker driver ")
}
a.driver = d
}
a.resources = NewResourceTracker(&a.cfg)
for _, sup := range a.onStartup {
sup()
}
return a
}
func (a *agent) addStartup(sup func()) {
a.onStartup = append(a.onStartup, sup)
}
// WithAsync Enables Async operations on the agent
func WithAsync(dqda DequeueDataAccess) Option {
return func(a *agent) error {
a.addStartup(func() {
if !a.shutWg.AddSession(1) {
logrus.Fatal("cannot start agent, unable to add session")
}
go a.asyncDequeue(dqda) // safe shutdown can nanny this fine
})
return nil
}
}
// WithConfig sets the agent config to the provided config
func WithConfig(cfg *Config) Option {
return func(a *agent) error {
a.cfg = *cfg
return nil
}
}
// WithDockerDriver Provides a customer driver to agent
func WithDockerDriver(drv drivers.Driver) Option {
return func(a *agent) error {
if a.driver != nil {
return errors.New("cannot add driver to agent, driver already exists")
}
a.driver = drv
return nil
}
}
// WithCallOverrider registers register a CallOverrider to modify a Call and extensions on call construction
func WithCallOverrider(fn CallOverrider) Option {
return func(a *agent) error {
if a.callOverrider != nil {
return errors.New("lb-agent call overriders already exists")
}
a.callOverrider = fn
return nil
}
}
// NewDockerDriver creates a default docker driver from agent config
func NewDockerDriver(cfg *Config) (drivers.Driver, error) {
return drivers.New("docker", drivers.Config{
DockerNetworks: cfg.DockerNetworks,
DockerLoadFile: cfg.DockerLoadFile,
ServerVersion: cfg.MinDockerVersion,
PreForkPoolSize: cfg.PreForkPoolSize,
PreForkImage: cfg.PreForkImage,
PreForkCmd: cfg.PreForkCmd,
PreForkUseOnce: cfg.PreForkUseOnce,
PreForkNetworks: cfg.PreForkNetworks,
MaxTmpFsInodes: cfg.MaxTmpFsInodes,
EnableReadOnlyRootFs: !cfg.DisableReadOnlyRootFs,
MaxRetries: cfg.MaxDockerRetries,
ContainerLabelTag: cfg.ContainerLabelTag,
})
}
func (a *agent) Close() error {
var err error
// wait for ongoing sessions
a.shutWg.CloseGroup()
a.shutonce.Do(func() {
// now close docker layer
if a.driver != nil {
err = a.driver.Close()
}
})
return err
}
func (a *agent) Submit(callI Call) error {
call := callI.(*call)
ctx, span := trace.StartSpan(call.req.Context(), "agent_submit")
defer span.End()
statsCalls(ctx)
if !a.shutWg.AddSession(1) {
statsTooBusy(ctx)
return models.ErrCallTimeoutServerBusy
}
defer a.shutWg.DoneSession()
err := a.submit(ctx, call)
return err
}
func (a *agent) startStateTrackers(ctx context.Context, call *call) {
call.requestState = NewRequestState()
}
func (a *agent) endStateTrackers(ctx context.Context, call *call) {
call.requestState.UpdateState(ctx, RequestStateDone, call.slots)
}
func (a *agent) submit(ctx context.Context, call *call) error {
statsEnqueue(ctx)
a.startStateTrackers(ctx, call)
defer a.endStateTrackers(ctx, call)
slot, err := a.getSlot(ctx, call)
if err != nil {
return a.handleCallEnd(ctx, call, slot, err, false)
}
err = call.Start(ctx)
if err != nil {
return a.handleCallEnd(ctx, call, slot, err, false)
}
statsDequeue(ctx)
statsStartRun(ctx)
// We are about to execute the function, set container Exec Deadline (call.Timeout)
slotCtx, cancel := context.WithTimeout(ctx, time.Duration(call.Timeout)*time.Second)
defer cancel()
// Pass this error (nil or otherwise) to end directly, to store status, etc.
err = slot.exec(slotCtx, call)
return a.handleCallEnd(ctx, call, slot, err, true)
}
func (a *agent) handleCallEnd(ctx context.Context, call *call, slot Slot, err error, isStarted bool) error {
if slot != nil {
slot.Close()
}
// This means call was routed (executed)
if isStarted {
call.End(ctx, err)
statsStopRun(ctx)
if err == nil {
statsComplete(ctx)
} else if err == context.DeadlineExceeded {
statsTimedout(ctx)
return models.ErrCallTimeout
}
} else {
statsDequeue(ctx)
if err == models.ErrCallTimeoutServerBusy || err == context.DeadlineExceeded {
statsTooBusy(ctx)
return models.ErrCallTimeoutServerBusy
}
}
if err == context.Canceled {
statsCanceled(ctx)
} else if err != nil {
statsErrors(ctx)
}
return err
}
// getSlot returns a Slot (or error) for the request to run. This will wait
// for other containers to become idle or it may wait for resources to become
// available to launch a new container.
func (a *agent) getSlot(ctx context.Context, call *call) (Slot, error) {
if call.Type == models.TypeAsync {
// *) for async, slot deadline is also call.Timeout. This is because we would like to
// allocate enough time for docker-pull, slot-wait, docker-start, etc.
// and also make sure we have call.Timeout inside the container. Total time
// to run an async becomes 2 * call.Timeout.
// *) for sync, there's no slot deadline, the timeout is controlled by http-client
// context (or runner gRPC context)
tmp, cancel := context.WithTimeout(ctx, time.Duration(call.Timeout)*time.Second)
ctx = tmp
defer cancel()
}
ctx, span := trace.StartSpan(ctx, "agent_get_slot")
defer span.End()
// For hot requests, we use a long lived slot queue, which we use to manage hot containers
var isNew bool
if call.slotHashId == "" {
call.slotHashId = getSlotQueueKey(call)
}
call.slots, isNew = a.slotMgr.getSlotQueue(call.slotHashId)
call.requestState.UpdateState(ctx, RequestStateWait, call.slots)
// setup slot caller with a ctx that gets cancelled once waitHot() is completed.
// This allows runHot() to detect if original caller has been serviced by
// another container or if original caller was disconnected.
caller := &slotCaller{}
{
ctx, cancel := context.WithCancel(ctx)
defer cancel()
caller.done = ctx.Done()
caller.notify = make(chan error)
}
if isNew {
go a.hotLauncher(ctx, call, caller)
}
s, err := a.waitHot(ctx, call, caller)
return s, err
}
// hotLauncher is spawned in a go routine for each slot queue to monitor stats and launch hot
// containers if needed. Upon shutdown or activity timeout, hotLauncher exits and during exit,
// it destroys the slot queue.
func (a *agent) hotLauncher(ctx context.Context, call *call, caller *slotCaller) {
// Let use 60 minutes or 2 * IdleTimeout as hot queue idle timeout, pick
// whichever is longer. If in this time, there's no activity, then
// we destroy the hot queue.
timeout := a.cfg.HotLauncherTimeout
idleTimeout := time.Duration(call.IdleTimeout) * time.Second * 2
if timeout < idleTimeout {
timeout = idleTimeout
}
logger := common.Logger(ctx)
logger.WithField("launcher_timeout", timeout).Debug("Hot function launcher starting")
// IMPORTANT: get a context that has a child span / logger but NO timeout
// TODO this is a 'FollowsFrom'
ctx = common.BackgroundContext(ctx)
ctx, span := trace.StartSpan(ctx, "agent_hot_launcher")
defer span.End()
for {
ctx, cancel := context.WithTimeout(ctx, timeout)
a.checkLaunch(ctx, call, *caller)
select {
case <-a.shutWg.Closer(): // server shutdown
cancel()
return
case <-ctx.Done(): // timed out
cancel()
if a.slotMgr.deleteSlotQueue(call.slots) {
logger.Debug("Hot function launcher timed out")
return
}
case caller = <-call.slots.signaller:
cancel()
}
}
}
func tryNotify(notifyChan chan error, err error) {
if notifyChan != nil && err != nil {
select {
case notifyChan <- err:
default:
}
}
}
func (a *agent) checkLaunch(ctx context.Context, call *call, caller slotCaller) {
curStats := call.slots.getStats()
isNB := a.cfg.EnableNBResourceTracker
if !isNewContainerNeeded(&curStats) {
return
}
state := NewContainerState()
state.UpdateState(ctx, ContainerStateWait, call.slots)
mem := call.Memory + uint64(call.TmpFsSize)
var notifyChans []chan struct{}
var tok ResourceToken
// WARNING: Tricky flow below. We are here because: isNewContainerNeeded is true,
// in other words, we need to launch a new container at this time due to high load.
//
// For non-blocking mode, this means, if we cannot acquire resources (cpu+mem), then we need
// to notify the caller through notifyChan. This is not perfect as the callers and
// checkLaunch do not match 1-1. But this is OK, we can notify *any* waiter that
// has signalled us, this is because non-blocking mode is a system wide setting.
// The notifications are lossy, but callers will signal/poll again if this is the case
// or this may not matter if they've already acquired an empty slot.
//
// For Non-blocking mode, a.cfg.HotPoll should not be set to too high since a missed
// notify event from here will add a.cfg.HotPoll msec latency. Setting a.cfg.HotPoll may
// be an acceptable workaround for the short term since non-blocking mode likely to reduce
// the number of waiters which perhaps could compensate for more frequent polling.
//
// Non-blocking mode only applies to cpu+mem, and if isNewContainerNeeded decided that we do not
// need to start a new container, then waiters will wait.
select {
case tok = <-a.resources.GetResourceToken(ctx, mem, call.CPUs, isNB):
case <-time.After(a.cfg.HotPoll):
// Request routines are polling us with this a.cfg.HotPoll frequency. We can use this
// same timer to assume that we waited for cpu/mem long enough. Let's try to evict an
// idle container. We do this by submitting a non-blocking request and evicting required
// amount of resources.
select {
case tok = <-a.resources.GetResourceToken(ctx, mem, call.CPUs, true):
case <-ctx.Done(): // timeout
case <-a.shutWg.Closer(): // server shutdown
}
case <-ctx.Done(): // timeout
case <-a.shutWg.Closer(): // server shutdown
}
if tok != nil {
if tok.Error() != nil {
if tok.Error() != CapacityFull {
tryNotify(caller.notify, tok.Error())
} else {
needMem, needCpu := tok.NeededCapacity()
notifyChans = a.evictor.PerformEviction(call.slotHashId, needMem, uint64(needCpu))
// For Non-blocking mode, if there's nothing to evict, we emit 503.
if len(notifyChans) == 0 && isNB {
tryNotify(caller.notify, models.ErrCallTimeoutServerBusy)
}
}
} else if a.shutWg.AddSession(1) {
go func() {
// NOTE: runHot will not inherit the timeout from ctx (ignore timings)
a.runHot(ctx, caller, call, tok, state)
a.shutWg.DoneSession()
}()
// early return (do not allow container state to switch to ContainerStateDone)
return
}
statsUtilization(ctx, a.resources.GetUtilization())
tok.Close()
}
defer state.UpdateState(ctx, ContainerStateDone, call.slots)
// IMPORTANT: we wait here for any possible evictions to finalize. Otherwise
// hotLauncher could call checkLaunch again and cause a capacity full (http 503)
// error.
for _, wait := range notifyChans {
select {
case <-wait:
case <-ctx.Done(): // timeout
return
case <-a.shutWg.Closer(): // server shutdown
return
}
}
}
// waitHot pings and waits for a hot container from the slot queue
func (a *agent) waitHot(ctx context.Context, call *call, caller *slotCaller) (Slot, error) {
ctx, span := trace.StartSpan(ctx, "agent_wait_hot")
defer span.End()
ctx, cancel := context.WithCancel(ctx)
defer cancel() // shut down dequeuer if we grab a slot
ch := call.slots.startDequeuer(ctx)
// 1) if we can get a slot immediately, grab it.
// 2) if we don't, send a signaller every x msecs until we do.
sleep := 1 * time.Microsecond // pad, so time.After doesn't send immediately
for {
select {
case err := <-caller.notify:
return nil, err
case s := <-ch:
if call.slots.acquireSlot(s) {
if s.slot.Error() != nil {
s.slot.Close()
return nil, s.slot.Error()
}
return s.slot, nil
}
// we failed to take ownership of the token (eg. container idle timeout) => try again
case <-ctx.Done():
return nil, ctx.Err()
case <-a.shutWg.Closer(): // server shutdown
return nil, models.ErrCallTimeoutServerBusy
case <-time.After(sleep):
// ping dequeuer again
}
// set sleep to x msecs after first iteration
sleep = a.cfg.HotPoll
// send a notification to launchHot()
select {
case call.slots.signaller <- caller:
default:
}
}
}
// implements Slot
type hotSlot struct {
done chan struct{} // signal we are done with slot
container *container // TODO mask this
cfg *Config
fatalErr error
containerSpan trace.SpanContext
}
func (s *hotSlot) Close() error {
close(s.done)
return nil
}
func (s *hotSlot) Error() error {
return s.fatalErr
}
func (s *hotSlot) trySetError(err error) {
if s.fatalErr == nil {
s.fatalErr = err
}
}
func (s *hotSlot) exec(ctx context.Context, call *call) error {
ctx, span := trace.StartSpan(ctx, "agent_hot_exec")
defer span.End()
call.requestState.UpdateState(ctx, RequestStateExec, call.slots)
// link the container id and id in the logs [for us!]
common.Logger(ctx).WithField("container_id", s.container.id).Info("starting call")
// link the container span to ours for additional context (start/freeze/etc.)
span.AddLink(trace.Link{
TraceID: s.containerSpan.TraceID,
SpanID: s.containerSpan.SpanID,
Type: trace.LinkTypeChild,
})
call.req = call.req.WithContext(ctx) // TODO this is funny biz reed is bad
return s.dispatch(ctx, call)
}
var removeHeaders = map[string]bool{
"connection": true,
"keep-alive": true,
"trailer": true,
"transfer-encoding": true,
"te": true,
"upgrade": true,
"authorization": true,
}
func createUDSRequest(ctx context.Context, call *call) *http.Request {
req, err := http.NewRequest("POST", "http://localhost/call", call.req.Body)
if err != nil {
common.Logger(ctx).WithError(err).Error("somebody put a bad url in the call http request. 10 lashes.")
panic(err)
}
// Set the context on the request to make sure transport and client handle
// it properly and close connections at the end, e.g. when using UDS.
req = req.WithContext(ctx)
req.Header = make(http.Header)
for k, vs := range call.req.Header {
if !removeHeaders[strings.ToLower(k)] {
for _, v := range vs {
req.Header.Add(k, v)
}
}
}
req.Header.Set("Fn-Call-Id", call.ID)
deadline, ok := ctx.Deadline()
if ok {
deadlineStr := deadline.Format(time.RFC3339)
req.Header.Set("Fn-Deadline", deadlineStr)
}
return req
}
func (s *hotSlot) dispatch(ctx context.Context, call *call) error {
ctx, span := trace.StartSpan(ctx, "agent_dispatch_httpstream")
defer span.End()
// TODO it's possible we can get rid of this (after getting rid of logs API) - may need for call id/debug mode still
// TODO there's a timeout race for swapping this back if the container doesn't get killed for timing out, and don't you forget it
swapBack := s.container.swap(call.stderr, &call.Stats)
defer swapBack()
resp, err := s.container.udsClient.Do(createUDSRequest(ctx, call))
if err != nil {
// IMPORTANT: Container contract: If http-uds errors/timeout, container cannot continue
s.trySetError(err)
// first filter out timeouts
if ctx.Err() == context.DeadlineExceeded {
return context.DeadlineExceeded
}
return models.ErrFunctionResponse
}
defer resp.Body.Close()
common.Logger(ctx).WithField("resp", resp).Debug("Got resp from UDS socket")
ioErrChan := make(chan error, 1)
go func() {
ioErrChan <- s.writeResp(ctx, s.cfg.MaxResponseSize, resp, call.respWriter)
}()
select {
case ioErr := <-ioErrChan:
return ioErr
case <-ctx.Done():
if ctx.Err() == context.DeadlineExceeded {
// IMPORTANT: Container contract: If http-uds timeout, container cannot continue
s.trySetError(ctx.Err())
}
return ctx.Err()
}
}
func (s *hotSlot) writeResp(ctx context.Context, max uint64, resp *http.Response, w io.Writer) error {
rw, ok := w.(http.ResponseWriter)
if !ok {
// WARNING: this bypasses container contract translation. Assuming this is
// async mode, where we are storing response in call.stderr.
w = common.NewClampWriter(w, max, models.ErrFunctionResponseTooBig)
return resp.Write(w)
}
// IMPORTANT: Container contract: Enforce 200/502/504 expections
switch resp.StatusCode {
case http.StatusOK:
// FDK processed the request OK
case http.StatusBadGateway:
// FDK detected failure, container can continue
return models.ErrFunctionFailed
case http.StatusGatewayTimeout:
// FDK detected timeout, respond as if ctx expired, this gets translated & handled in handleCallEnd()
return context.DeadlineExceeded
default:
// Any other code. Possible FDK failure. We shutdown the container
s.trySetError(fmt.Errorf("FDK Error, invalid status code %d", resp.StatusCode))
return models.ErrFunctionInvalidResponse
}
rw = newSizerRespWriter(max, rw)
rw.WriteHeader(http.StatusOK)
// WARNING: is the following header copy safe?
// if we're writing directly to the response writer, we need to set headers
// and only copy the body. resp.Write would copy a full
// http request into the response body (not what we want).
for k, vs := range resp.Header {
for _, v := range vs {
rw.Header().Add(k, v)
}
}
_, ioErr := io.Copy(rw, resp.Body)
return ioErr
}
// XXX(reed): this is a remnant of old io.pipe plumbing, we need to get rid of
// the buffers from the front-end in actuality, but only after removing other formats... so here, eat this
type sizerRespWriter struct {
http.ResponseWriter
w io.Writer
}
var _ http.ResponseWriter = new(sizerRespWriter)
func newSizerRespWriter(max uint64, rw http.ResponseWriter) http.ResponseWriter {
return &sizerRespWriter{
ResponseWriter: rw,
w: common.NewClampWriter(rw, max, models.ErrFunctionResponseTooBig),
}
}
func (s *sizerRespWriter) Write(b []byte) (int, error) { return s.w.Write(b) }
// Try to queue an error to the error channel if possible.
func tryQueueErr(err error, ch chan error) error {
if err != nil {
select {
case ch <- err:
default:
}
}
return err
}
func (a *agent) runHot(ctx context.Context, caller slotCaller, call *call, tok ResourceToken, state ContainerState) {
// IMPORTANT: get a context that has a child span / logger but NO timeout
// TODO this is a 'FollowsFrom'
ctx = common.BackgroundContext(ctx)
ctx, span := trace.StartSpan(ctx, "agent_run_hot")
defer span.End()
var container *container
var cookie drivers.Cookie
var err error
id := id.New().String()
logger := logrus.WithFields(logrus.Fields{"id": id, "app_id": call.AppID, "fn_id": call.FnID, "image": call.Image, "memory": call.Memory, "cpus": call.CPUs, "idle_timeout": call.IdleTimeout})
ctx, cancel := context.WithCancel(common.WithLogger(ctx, logger))
initialized := make(chan struct{}) // when closed, container is ready to handle requests
udsWait := make(chan error, 1) // track UDS state and errors
errQueue := make(chan error, 1) // errors to be reflected back to the slot queue
evictor := a.evictor.CreateEvictToken(call.slotHashId, call.Memory+uint64(call.TmpFsSize), uint64(call.CPUs))
statsUtilization(ctx, a.resources.GetUtilization())
state.UpdateState(ctx, ContainerStateStart, call.slots)
// stack unwind spelled out with strict ordering below.
defer func() {
// IMPORTANT: we ignore any errors due to eviction and do not reflect these to clients.
if !evictor.isEvicted() {
select {
case <-initialized:
default:
tryQueueErr(models.ErrContainerInitFail, errQueue)
}
select {
case err := <-errQueue:
call.slots.queueSlot(&hotSlot{done: make(chan struct{}), fatalErr: err})
default:
}
}
// shutdown the container and related I/O operations and go routines
cancel()
// IMPORTANT: for release cookie (remove container), make sure ctx below has no timeout.
if cookie != nil {
cookie.Close(common.BackgroundContext(ctx))
}
if container != nil {
container.Close()
}
lastState := state.GetState()
state.UpdateState(ctx, ContainerStateDone, call.slots)
tok.Close() // release cpu/mem
// IMPORTANT: evict token is deleted *after* resource token.
// This ordering allows resource token to be freed first, which means once evict token
// is deleted, eviction is considered to be completed.
a.evictor.DeleteEvictToken(evictor)
statsUtilization(ctx, a.resources.GetUtilization())
if evictor.isEvicted() {
logger.Debugf("Hot function evicted")
statsContainerEvicted(ctx, lastState)
}
}()
// Monitor initialization and evictability. Closes 'initialized' channel
// to hand over the processing to main request processing go-routine
go func() {
for {
select {
case err := <-udsWait:
if tryQueueErr(err, errQueue) != nil {
cancel()
} else {
close(initialized)
}
return
case <-ctx.Done(): // container shutdown
return
case <-a.shutWg.Closer(): // agent shutdown
cancel()
return
case <-caller.done: // original caller disconnected or serviced by another container?
evictor.SetEvictable(true)
caller.done = nil // block 'caller.done' after this point
case <-evictor.C: // eviction
cancel()
return
}
}
}()
container = newHotContainer(ctx, call, &a.cfg, id, udsWait)
if container == nil {
return
}
cookie, err = a.driver.CreateCookie(ctx, container)
if tryQueueErr(err, errQueue) != nil {
return
}
needsPull, err := cookie.ValidateImage(ctx)
if tryQueueErr(err, errQueue) != nil {
return
}
if needsPull {
ctx, cancel := context.WithTimeout(ctx, a.cfg.HotPullTimeout)
err = cookie.PullImage(ctx)
cancel()
if ctx.Err() == context.DeadlineExceeded {
err = models.ErrDockerPullTimeout
}
if tryQueueErr(err, errQueue) != nil {
return
}
}
err = cookie.CreateContainer(ctx)
if tryQueueErr(err, errQueue) != nil {
return
}
waiter, err := cookie.Run(ctx)
if tryQueueErr(err, errQueue) != nil {
return
}
// Main request processing go-routine
go func() {
defer cancel() // also close if we get an agent shutdown / idle timeout
// We record init wait for three basic states below: "initialized", "canceled", "timedout"
// Notice how we do not distinguish between agent-shutdown, eviction, ctx.Done, etc. This is
// because monitoring go-routine may pick these events earlier and cancel the ctx.
initStart := time.Now()
// INIT BARRIER HERE. Wait for the initialization go-routine signal
select {
case <-initialized:
statsContainerUDSInitLatency(ctx, initStart, time.Now(), "initialized")
case <-a.shutWg.Closer(): // agent shutdown
statsContainerUDSInitLatency(ctx, initStart, time.Now(), "canceled")
return
case <-ctx.Done():
statsContainerUDSInitLatency(ctx, initStart, time.Now(), "canceled")
return
case <-evictor.C: // eviction
statsContainerUDSInitLatency(ctx, initStart, time.Now(), "canceled")
return
case <-time.After(a.cfg.HotStartTimeout):
statsContainerUDSInitLatency(ctx, initStart, time.Now(), "timedout")
tryQueueErr(models.ErrContainerInitTimeout, errQueue)
return
}
for {
// Below we are rather defensive and poll on evictor/ctx
// to reduce the likelyhood of attempting to queue a hotSlot when these
// two cases occur.
select {
case <-ctx.Done():
return
case <-evictor.C: // eviction
return
default:
}
slot := &hotSlot{
done: make(chan struct{}),
container: container,
cfg: &a.cfg,
containerSpan: trace.FromContext(ctx).SpanContext(),
}
if !a.runHotReq(ctx, call, state, logger, cookie, slot, evictor) {
return
}
// wait for this call to finish
// NOTE do NOT select with shutdown / other channels. slot handles this.
<-slot.done
if slot.fatalErr != nil {
logger.WithError(slot.fatalErr).Info("hot function terminating")
return
}
}
}()
runRes := waiter.Wait(ctx)
if runRes != nil && runRes.Error() != context.Canceled {
logger.WithError(runRes.Error()).Info("hot function terminated")
}
}
//checkSocketDestination verifies that the socket file created by the FDK is valid and permitted - notably verifying that any symlinks are relative to the socket dir
func checkSocketDestination(filename string) error {
finfo, err := os.Lstat(filename)
if err != nil {
return fmt.Errorf("error statting unix socket link file %s", err)
}
if (finfo.Mode() & os.ModeSymlink) > 0 {
linkDest, err := os.Readlink(filename)
if err != nil {
return fmt.Errorf("error reading unix socket symlink destination %s", err)
}
if filepath.Dir(linkDest) != "." {
return fmt.Errorf("invalid unix socket symlink, symlinks must be relative within the unix socket directory")
}
}
// stat the absolute path and check it is a socket
absInfo, err := os.Stat(filename)
if err != nil {
return fmt.Errorf("unable to stat unix socket file %s", err)
}
if absInfo.Mode()&os.ModeSocket == 0 {
return fmt.Errorf("listener file is not a socket")
}
return nil
}
func inotifyAwait(ctx context.Context, iofsDir string, udsWait chan error) {
ctx, span := trace.StartSpan(ctx, "inotify_await")
defer span.End()
logger := common.Logger(ctx)
// Here we create the fs notify (inotify) synchronously and once that is
// setup, then fork off our async go-routine. Basically fsnotify should be enabled
// before we launch the container in order not to miss any events.
fsWatcher, err := fsnotify.NewWatcher()
if err != nil {