Merge pull request #70 from ekristen/beta-signals

refactor: bring signals package in house

Author: ekristen

go.mod

@@ -12,7 +12,6 @@ require (
 	github.com/h2non/filetype v1.1.3
 	github.com/krolaw/zipstream v0.0.0-20180621105154-0a2661891f94
 	github.com/pelletier/go-toml/v2 v2.2.3
-	github.com/rancher/wrangler v1.1.2
 	github.com/sirupsen/logrus v1.9.3
 	github.com/stretchr/testify v1.9.0
 	github.com/ulikunitz/xz v0.5.12

go.sum

@@ -85,8 +85,6 @@ github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/rancher/wrangler v1.1.2 h1:oXbXo9k7y/H4drUpb4RM1c++vT9O3rpoNEfyusGykiU=
-github.com/rancher/wrangler v1.1.2/go.mod h1:2k9MyhlBdjcutcBGoOJSUAz0HgDAXnMjv81d3n/AaQc=
 github.com/rogpeppe/fastuuid v1.1.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=

main.go

@@ -5,11 +5,11 @@ import (
 	"path"
 
 	"github.com/apex/log"
-	"github.com/rancher/wrangler/pkg/signals"
 	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 
 	"github.com/ekristen/distillery/pkg/common"
+	"github.com/ekristen/distillery/pkg/signals"
 
 	_ "github.com/ekristen/distillery/pkg/commands/clean"
 	_ "github.com/ekristen/distillery/pkg/commands/completion"

pkg/signals/signals.go

@@ -0,0 +1,72 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package signals
+
+import (
+	"context"
+	"os"
+	"os/signal"
+
+	"github.com/sirupsen/logrus"
+)
+
+var onlyOneSignalHandler = make(chan struct{})
+var shutdownHandler chan os.Signal
+
+// SetupSignalHandler registered for SIGTERM and SIGINT. A stop channel is returned
+// which is closed on one of these signals. If a second signal is caught, the program
+// is terminated with exit code 1.
+// Only one of SetupSignalContext and SetupSignalHandler should be called, and only can
+// be called once.
+func SetupSignalHandler() <-chan struct{} {
+	return SetupSignalContext().Done()
+}
+
+// SetupSignalContext is same as SetupSignalHandler, but a context.Context is returned.
+// Only one of SetupSignalContext and SetupSignalHandler should be called, and only can
+// be called once.
+func SetupSignalContext() context.Context {
+	close(onlyOneSignalHandler) // panics when called twice
+
+	shutdownHandler = make(chan os.Signal, 2)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	signal.Notify(shutdownHandler, shutdownSignals...)
+	go func() {
+		s := <-shutdownHandler
+		logrus.Warnf("signal received: %q, canceling context...", s)
+		cancel()
+		s = <-shutdownHandler
+		logrus.Warnf("second signal received: %q, exiting...", s)
+		os.Exit(1) // second signal. Exit directly.
+	}()
+
+	return ctx
+}
+
+// RequestShutdown emulates a received event that is considered as shutdown signal (SIGTERM/SIGINT)
+// This returns whether a handler was notified
+func RequestShutdown() bool {
+	if shutdownHandler != nil {
+		select {
+		case shutdownHandler <- shutdownSignals[0]:
+			return true
+		default:
+		}
+	}
+
+	return false
+}

pkg/signals/signals_posix.go

@@ -0,0 +1,26 @@
+//go:build !windows
+
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package signals
+
+import (
+	"os"
+	"syscall"
+)
+
+var shutdownSignals = []os.Signal{os.Interrupt, syscall.SIGTERM}

pkg/signals/signals_windows.go

@@ -0,0 +1,23 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package signals
+
+import (
+	"os"
+)
+
+var shutdownSignals = []os.Signal{os.Interrupt}