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4ccde8897e
* fn: lb and pure-runner with non-blocking agent *) Removed pure-runner capacity tracking code. This did not play well with internal agent resource tracker. *) In LB and runner gRPC comm, removed ACK. Now, upon TryCall, pure-runner quickly proceeds to call Submit. This is good since at this stage pure-runner already has all relevant data to initiate the call. *) Unless pure-runner emits a NACK, LB immediately streams http body to runners. *) For retriable requests added a CachedReader for http.Request Body. *) Idempotenty/retry is similar to previous code. After initial success in Engament, after attempting a TryCall, unless we receive NACK, we cannot retry that call. *) ch and naive places now wraps each TryExec with a cancellable context to clean up gRPC contexts quicker. * fn: err for simpler one-time read GetBody approach This allows for a more flexible approach since we let users to define GetBody() to allow repetitive http body read. In default LB case, LB executes a one-time io.ReadAll and sets of GetBody, which is detected by RunnerCall.RequestBody(). * fn: additional check for non-nil req.body * fn: attempt to override IO errors with ctx for TryExec * fn: system-tests log dest * fn: LB: EOF send handling * fn: logging for partial IO * fn: use buffer pool for IO storage in lb agent * fn: pure runner should use chunks for data msgs * fn: required config validations and pass APIErrors * fn: additional tests and gRPC proto simplification *) remove ACK/NACK messages as Finish message type works OK for this purpose. *) return resp in api tests for check for status code *) empty body json test in api tests for lb & pure-runner * fn: buffer adjustments *) setRequestBody result handling correction *) switch to bytes.Reader for read-only safety *) io.EOF can be returned for non-nil Body in request. * fn: clarify detection of 503 / Server Too Busy
92 lines
2.3 KiB
Go
92 lines
2.3 KiB
Go
/* The consistent hash ring from the original fnlb.
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The behaviour of this depends on changes to the runner list leaving it relatively stable.
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*/
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package runnerpool
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import (
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"context"
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"time"
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"github.com/fnproject/fn/api/common"
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"github.com/fnproject/fn/api/models"
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"github.com/dchest/siphash"
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"github.com/sirupsen/logrus"
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)
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type chPlacer struct{}
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func NewCHPlacer() Placer {
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logrus.Info("Creating new CH runnerpool placer")
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return &chPlacer{}
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}
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// This borrows the CH placement algorithm from the original FNLB.
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// Because we ask a runner to accept load (queuing on the LB rather than on the nodes), we don't use
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// the LB_WAIT to drive placement decisions: runners only accept work if they have the capacity for it.
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func (p *chPlacer) PlaceCall(rp RunnerPool, ctx context.Context, call RunnerCall) error {
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// The key is just the path in this case
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key := call.Model().Path
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sum64 := siphash.Hash(0, 0x4c617279426f6174, []byte(key))
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timeout := time.After(call.LbDeadline().Sub(time.Now()))
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for {
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runners, err := rp.Runners(call)
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if err != nil {
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logrus.WithError(err).Error("Failed to find runners for call")
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} else {
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i := int(jumpConsistentHash(sum64, int32(len(runners))))
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for j := 0; j < len(runners); j++ {
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select {
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case <-ctx.Done():
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return models.ErrCallTimeoutServerBusy
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case <-timeout:
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return models.ErrCallTimeoutServerBusy
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default:
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}
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r := runners[i]
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tryCtx, tryCancel := context.WithCancel(ctx)
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placed, err := r.TryExec(tryCtx, call)
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tryCancel()
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if err != nil {
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logrus.WithError(err).Error("Failed during call placement")
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}
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if placed {
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return err
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}
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i = (i + 1) % len(runners)
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}
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}
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remaining := call.LbDeadline().Sub(time.Now())
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if remaining <= 0 {
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return models.ErrCallTimeoutServerBusy
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}
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// backoff
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select {
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case <-ctx.Done():
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return models.ErrCallTimeoutServerBusy
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case <-timeout:
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return models.ErrCallTimeoutServerBusy
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case <-time.After(common.MinDuration(retryWaitInterval, remaining)):
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}
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}
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}
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// A Fast, Minimal Memory, Consistent Hash Algorithm:
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// https://arxiv.org/ftp/arxiv/papers/1406/1406.2294.pdf
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func jumpConsistentHash(key uint64, num_buckets int32) int32 {
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var b, j int64 = -1, 0
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for j < int64(num_buckets) {
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b = j
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key = key*2862933555777941757 + 1
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j = (b + 1) * int64((1<<31)/(key>>33)+1)
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}
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return int32(b)
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}
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