From de24c5b7ec44df2d8e0ef42a24b8e4d76fddcba7 Mon Sep 17 00:00:00 2001 From: Frederic Branczyk Date: Sat, 7 Oct 2017 13:01:37 +0200 Subject: [PATCH] Fix inhibit race (#1032) * inhibit: restructure stop logic, to prevent race condition * vendor oklog/oklog/pkg/group --- inhibit/inhibit.go | 55 +++-- vendor/github.com/oklog/oklog/LICENSE | 201 ++++++++++++++++++ .../github.com/oklog/oklog/pkg/group/group.go | 62 ++++++ vendor/vendor.json | 6 + 4 files changed, 306 insertions(+), 18 deletions(-) create mode 100644 vendor/github.com/oklog/oklog/LICENSE create mode 100644 vendor/github.com/oklog/oklog/pkg/group/group.go diff --git a/inhibit/inhibit.go b/inhibit/inhibit.go index 101846a6..9d1cb356 100644 --- a/inhibit/inhibit.go +++ b/inhibit/inhibit.go @@ -14,10 +14,12 @@ package inhibit import ( + "context" "fmt" "sync" "time" + "github.com/oklog/oklog/pkg/group" "github.com/prometheus/common/log" "github.com/prometheus/common/model" @@ -33,8 +35,8 @@ type Inhibitor struct { rules []*InhibitRule marker types.Marker - mtx sync.RWMutex - stopc chan struct{} + mtx sync.RWMutex + cancel func() } // NewInhibitor returns a new Inhibitor. @@ -50,33 +52,26 @@ func NewInhibitor(ap provider.Alerts, rs []*config.InhibitRule, mk types.Marker) return ih } -func (ih *Inhibitor) runGC() { +func (ih *Inhibitor) runGC(ctx context.Context) { for { select { case <-time.After(15 * time.Minute): for _, r := range ih.rules { r.gc() } - case <-ih.stopc: + case <-ctx.Done(): return } } } -// Run the Inihibitor's background processing. -func (ih *Inhibitor) Run() { - ih.mtx.Lock() - ih.stopc = make(chan struct{}) - ih.mtx.Unlock() - - go ih.runGC() - +func (ih *Inhibitor) run(ctx context.Context) { it := ih.alerts.Subscribe() defer it.Close() for { select { - case <-ih.stopc: + case <-ctx.Done(): return case a := <-it.Next(): if err := it.Err(); err != nil { @@ -98,17 +93,41 @@ func (ih *Inhibitor) Run() { } } +// Run the Inihibitor's background processing. +func (ih *Inhibitor) Run() { + var ( + g group.Group + ctx context.Context + ) + + ctx, ih.cancel = context.WithCancel(context.Background()) + gcCtx, gcCancel := context.WithCancel(ctx) + runCtx, runCancel := context.WithCancel(ctx) + + g.Add(func() error { + ih.runGC(gcCtx) + return nil + }, func(err error) { + gcCancel() + }) + g.Add(func() error { + ih.run(runCtx) + return nil + }, func(err error) { + runCancel() + }) + + g.Run() +} + // Stop the Inhibitor's background processing. func (ih *Inhibitor) Stop() { if ih == nil { return } - ih.mtx.Lock() - defer ih.mtx.Unlock() - if ih.stopc != nil { - close(ih.stopc) - ih.stopc = nil + if ih.cancel != nil { + ih.cancel() } } diff --git a/vendor/github.com/oklog/oklog/LICENSE b/vendor/github.com/oklog/oklog/LICENSE new file mode 100644 index 00000000..8dada3ed --- /dev/null +++ b/vendor/github.com/oklog/oklog/LICENSE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. 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It is +// somewhat similar to package errgroup, except it does not require actor +// goroutines to understand context semantics. This makes it suitable for use +// in more circumstances; for example, goroutines which are handling +// connections from net.Listeners, or scanning input from a closable io.Reader. +package group + +// Group collects actors (functions) and runs them concurrently. +// When one actor (function) returns, all actors are interrupted. +// The zero value of a Group is useful. +type Group struct { + actors []actor +} + +// Add an actor (function) to the group. Each actor must be pre-emptable by an +// interrupt function. That is, if interrupt is invoked, execute should return. +// Also, it must be safe to call interrupt even after execute has returned. +// +// The first actor (function) to return interrupts all running actors. +// The error is passed to the interrupt functions, and is returned by Run. +func (g *Group) Add(execute func() error, interrupt func(error)) { + g.actors = append(g.actors, actor{execute, interrupt}) +} + +// Run all actors (functions) concurrently. +// When the first actor returns, all others are interrupted. +// Run only returns when all actors have exited. +// Run returns the error returned by the first exiting actor. +func (g *Group) Run() error { + if len(g.actors) == 0 { + return nil + } + + // Run each actor. + errors := make(chan error, len(g.actors)) + for _, a := range g.actors { + go func(a actor) { + errors <- a.execute() + }(a) + } + + // Wait for the first actor to stop. + err := <-errors + + // Signal all actors to stop. + for _, a := range g.actors { + a.interrupt(err) + } + + // Wait for all actors to stop. + for i := 1; i < cap(errors); i++ { + <-errors + } + + // Return the original error. + return err +} + +type actor struct { + execute func() error + interrupt func(error) +} diff --git a/vendor/vendor.json b/vendor/vendor.json index f837ea09..ac4f2978 100644 --- a/vendor/vendor.json +++ b/vendor/vendor.json @@ -183,6 +183,12 @@ "revision": "db1efb556f84b25a0a13a04aad883943538ad2e0", "revisionTime": "2017-01-25T05:19:37Z" }, + { + "checksumSHA1": "gkyBg/2hcIWR/8qGEeGVoHwOyfo=", + "path": "github.com/oklog/oklog/pkg/group", + "revision": "f857583a70c345341d679b3f27aa542c8db70a21", + "revisionTime": "2017-09-18T07:00:58Z" + }, { "checksumSHA1": "8Y05Pz7onrQPcVWW6JStSsYRh6E=", "path": "github.com/pelletier/go-buffruneio",