b97609cd2c
Bring in some updates from the signal handling code in other projects: - Rename `signals` to more descriptive `interruptSignals`. - Add SIGHUP to unix shutdown signals. Rename `signalsigterm.go` to `signal_unix.go` accordingly. - Include extra detail in "Already shutting down..." messages log lines. - Pass a shutdown func into `webapi.go` rather than a channel. It's more obvious how to invoke a func, whereas a channel can be used in multiple ways.
74 lines
2.3 KiB
Go
74 lines
2.3 KiB
Go
// Copyright (c) 2013-2014 The btcsuite developers
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// Copyright (c) 2021 The Decred developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package main
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import (
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"context"
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"os"
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"os/signal"
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)
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// shutdownRequestChannel is used to initiate shutdown from one of the
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// subsystems using the same code paths as when an interrupt signal is received.
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var shutdownRequestChannel = make(chan struct{})
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// shutdownSignaled is closed whenever shutdown is invoked through an interrupt
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// signal or from an JSON-RPC stop request. Any contexts created using
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// withShutdownChannel are cancelled when this is closed.
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var shutdownSignaled = make(chan struct{})
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// interruptSignals defines the signals that are handled to do a clean shutdown.
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// Conditional compilation is used to also include SIGTERM and SIGHUP on Unix.
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var interruptSignals = []os.Signal{os.Interrupt}
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// withShutdownCancel creates a copy of a context that is cancelled whenever
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// shutdown is invoked through an interrupt signal or from an JSON-RPC stop
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// request.
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func withShutdownCancel(ctx context.Context) context.Context {
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ctx, cancel := context.WithCancel(ctx)
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go func() {
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<-shutdownSignaled
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cancel()
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}()
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return ctx
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}
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// requestShutdown signals for starting the clean shutdown of the process
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// through an internal component.
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func requestShutdown() {
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shutdownRequestChannel <- struct{}{}
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}
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// shutdownListener listens for shutdown requests and cancels all contexts
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// created from withShutdownCancel. This function never returns and is intended
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// to be spawned in a new goroutine.
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func shutdownListener() {
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interruptChannel := make(chan os.Signal, 1)
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signal.Notify(interruptChannel, interruptSignals...)
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// Listen for the initial shutdown signal
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select {
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case sig := <-interruptChannel:
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log.Infof("Received signal (%s). Shutting down...", sig)
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case <-shutdownRequestChannel:
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log.Info("Shutdown requested. Shutting down...")
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}
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// Cancel all contexts created from withShutdownCancel.
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close(shutdownSignaled)
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// Listen for any more shutdown signals and log that shutdown has already
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// been signaled.
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for {
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select {
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case sig := <-interruptChannel:
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log.Infof("Received signal (%s). Already shutting down...", sig)
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case <-shutdownRequestChannel:
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log.Info("Shutdown requested. Already shutting down...")
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}
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}
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}
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