lbcwallet/signal.go

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// Copyright (c) 2013-2014 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package main
import (
"os"
"os/signal"
)
// interruptChannel is used to receive SIGINT (Ctrl+C) signals.
var interruptChannel chan os.Signal
// addHandlerChannel is used to add an interrupt handler to the list of handlers
// to be invoked on SIGINT (Ctrl+C) signals.
var addHandlerChannel = make(chan func())
Modernize the RPC server. This is a rather monolithic commit that moves the old RPC server to its own package (rpc/legacyrpc), introduces a new RPC server using gRPC (rpc/rpcserver), and provides the ability to defer wallet loading until request at a later time by an RPC (--noinitialload). The legacy RPC server remains the default for now while the new gRPC server is not enabled by default. Enabling the new server requires setting a listen address (--experimenalrpclisten). This experimental flag is used to effectively feature gate the server until it is ready to use as a default. Both RPC servers can be run at the same time, but require binding to different listen addresses. In theory, with the legacy RPC server now living in its own package it should become much easier to unit test the handlers. This will be useful for any future changes to the package, as compatibility with Core's wallet is still desired. Type safety has also been improved in the legacy RPC server. Multiple handler types are now used for methods that do and do not require the RPC client as a dependency. This can statically help prevent nil pointer dereferences, and was very useful for catching bugs during refactoring. To synchronize the wallet loading process between the main package (the default) and through the gRPC WalletLoader service (with the --noinitialload option), as well as increasing the loose coupling of packages, a new wallet.Loader type has been added. All creating and loading of existing wallets is done through a single Loader instance, and callbacks can be attached to the instance to run after the wallet has been opened. This is how the legacy RPC server is associated with a loaded wallet, even after the wallet is loaded by a gRPC method in a completely unrelated package. Documentation for the new RPC server has been added to the rpc/documentation directory. The documentation includes a specification for the new RPC API, addresses how to make changes to the server implementation, and provides short example clients in several different languages. Some of the new RPC methods are not implementated exactly as described by the specification. These are considered bugs with the implementation, not the spec. Known bugs are commented as such.
2015-06-01 21:57:50 +02:00
// interruptHandlersDone is closed after all interrupt handlers run the first
// time an interrupt is signaled.
var interruptHandlersDone = make(chan struct{})
var simulateInterruptChannel = make(chan struct{}, 1)
// signals defines the signals that are handled to do a clean shutdown.
// Conditional compilation is used to also include SIGTERM on Unix.
var signals = []os.Signal{os.Interrupt}
Modernize the RPC server. This is a rather monolithic commit that moves the old RPC server to its own package (rpc/legacyrpc), introduces a new RPC server using gRPC (rpc/rpcserver), and provides the ability to defer wallet loading until request at a later time by an RPC (--noinitialload). The legacy RPC server remains the default for now while the new gRPC server is not enabled by default. Enabling the new server requires setting a listen address (--experimenalrpclisten). This experimental flag is used to effectively feature gate the server until it is ready to use as a default. Both RPC servers can be run at the same time, but require binding to different listen addresses. In theory, with the legacy RPC server now living in its own package it should become much easier to unit test the handlers. This will be useful for any future changes to the package, as compatibility with Core's wallet is still desired. Type safety has also been improved in the legacy RPC server. Multiple handler types are now used for methods that do and do not require the RPC client as a dependency. This can statically help prevent nil pointer dereferences, and was very useful for catching bugs during refactoring. To synchronize the wallet loading process between the main package (the default) and through the gRPC WalletLoader service (with the --noinitialload option), as well as increasing the loose coupling of packages, a new wallet.Loader type has been added. All creating and loading of existing wallets is done through a single Loader instance, and callbacks can be attached to the instance to run after the wallet has been opened. This is how the legacy RPC server is associated with a loaded wallet, even after the wallet is loaded by a gRPC method in a completely unrelated package. Documentation for the new RPC server has been added to the rpc/documentation directory. The documentation includes a specification for the new RPC API, addresses how to make changes to the server implementation, and provides short example clients in several different languages. Some of the new RPC methods are not implementated exactly as described by the specification. These are considered bugs with the implementation, not the spec. Known bugs are commented as such.
2015-06-01 21:57:50 +02:00
// simulateInterrupt requests invoking the clean termination process by an
// internal component instead of a SIGINT.
func simulateInterrupt() {
select {
case simulateInterruptChannel <- struct{}{}:
default:
}
}
// mainInterruptHandler listens for SIGINT (Ctrl+C) signals on the
// interruptChannel and invokes the registered interruptCallbacks accordingly.
// It also listens for callback registration. It must be run as a goroutine.
func mainInterruptHandler() {
// interruptCallbacks is a list of callbacks to invoke when a
// SIGINT (Ctrl+C) is received.
var interruptCallbacks []func()
Modernize the RPC server. This is a rather monolithic commit that moves the old RPC server to its own package (rpc/legacyrpc), introduces a new RPC server using gRPC (rpc/rpcserver), and provides the ability to defer wallet loading until request at a later time by an RPC (--noinitialload). The legacy RPC server remains the default for now while the new gRPC server is not enabled by default. Enabling the new server requires setting a listen address (--experimenalrpclisten). This experimental flag is used to effectively feature gate the server until it is ready to use as a default. Both RPC servers can be run at the same time, but require binding to different listen addresses. In theory, with the legacy RPC server now living in its own package it should become much easier to unit test the handlers. This will be useful for any future changes to the package, as compatibility with Core's wallet is still desired. Type safety has also been improved in the legacy RPC server. Multiple handler types are now used for methods that do and do not require the RPC client as a dependency. This can statically help prevent nil pointer dereferences, and was very useful for catching bugs during refactoring. To synchronize the wallet loading process between the main package (the default) and through the gRPC WalletLoader service (with the --noinitialload option), as well as increasing the loose coupling of packages, a new wallet.Loader type has been added. All creating and loading of existing wallets is done through a single Loader instance, and callbacks can be attached to the instance to run after the wallet has been opened. This is how the legacy RPC server is associated with a loaded wallet, even after the wallet is loaded by a gRPC method in a completely unrelated package. Documentation for the new RPC server has been added to the rpc/documentation directory. The documentation includes a specification for the new RPC API, addresses how to make changes to the server implementation, and provides short example clients in several different languages. Some of the new RPC methods are not implementated exactly as described by the specification. These are considered bugs with the implementation, not the spec. Known bugs are commented as such.
2015-06-01 21:57:50 +02:00
invokeCallbacks := func() {
// run handlers in LIFO order.
for i := range interruptCallbacks {
idx := len(interruptCallbacks) - 1 - i
interruptCallbacks[idx]()
}
close(interruptHandlersDone)
}
for {
select {
case sig := <-interruptChannel:
log.Infof("Received signal (%s). Shutting down...", sig)
Modernize the RPC server. This is a rather monolithic commit that moves the old RPC server to its own package (rpc/legacyrpc), introduces a new RPC server using gRPC (rpc/rpcserver), and provides the ability to defer wallet loading until request at a later time by an RPC (--noinitialload). The legacy RPC server remains the default for now while the new gRPC server is not enabled by default. Enabling the new server requires setting a listen address (--experimenalrpclisten). This experimental flag is used to effectively feature gate the server until it is ready to use as a default. Both RPC servers can be run at the same time, but require binding to different listen addresses. In theory, with the legacy RPC server now living in its own package it should become much easier to unit test the handlers. This will be useful for any future changes to the package, as compatibility with Core's wallet is still desired. Type safety has also been improved in the legacy RPC server. Multiple handler types are now used for methods that do and do not require the RPC client as a dependency. This can statically help prevent nil pointer dereferences, and was very useful for catching bugs during refactoring. To synchronize the wallet loading process between the main package (the default) and through the gRPC WalletLoader service (with the --noinitialload option), as well as increasing the loose coupling of packages, a new wallet.Loader type has been added. All creating and loading of existing wallets is done through a single Loader instance, and callbacks can be attached to the instance to run after the wallet has been opened. This is how the legacy RPC server is associated with a loaded wallet, even after the wallet is loaded by a gRPC method in a completely unrelated package. Documentation for the new RPC server has been added to the rpc/documentation directory. The documentation includes a specification for the new RPC API, addresses how to make changes to the server implementation, and provides short example clients in several different languages. Some of the new RPC methods are not implementated exactly as described by the specification. These are considered bugs with the implementation, not the spec. Known bugs are commented as such.
2015-06-01 21:57:50 +02:00
invokeCallbacks()
return
case <-simulateInterruptChannel:
log.Info("Received shutdown request. Shutting down...")
invokeCallbacks()
return
case handler := <-addHandlerChannel:
interruptCallbacks = append(interruptCallbacks, handler)
}
}
}
// addInterruptHandler adds a handler to call when a SIGINT (Ctrl+C) is
// received.
func addInterruptHandler(handler func()) {
// Create the channel and start the main interrupt handler which invokes
// all other callbacks and exits if not already done.
if interruptChannel == nil {
interruptChannel = make(chan os.Signal, 1)
signal.Notify(interruptChannel, signals...)
go mainInterruptHandler()
}
addHandlerChannel <- handler
}