vendor files

vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go

@@ -0,0 +1,163 @@
+/*
+Copyright 2014 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 runtime
+
+import (
+	"fmt"
+	"runtime"
+	"sync"
+	"time"
+
+	"github.com/golang/glog"
+)
+
+var (
+	// ReallyCrash controls the behavior of HandleCrash and now defaults
+	// true. It's still exposed so components can optionally set to false
+	// to restore prior behavior.
+	ReallyCrash = true
+)
+
+// PanicHandlers is a list of functions which will be invoked when a panic happens.
+var PanicHandlers = []func(interface{}){logPanic}
+
+// HandleCrash simply catches a crash and logs an error. Meant to be called via
+// defer.  Additional context-specific handlers can be provided, and will be
+// called in case of panic.  HandleCrash actually crashes, after calling the
+// handlers and logging the panic message.
+//
+// TODO: remove this function. We are switching to a world where it's safe for
+// apiserver to panic, since it will be restarted by kubelet. At the beginning
+// of the Kubernetes project, nothing was going to restart apiserver and so
+// catching panics was important. But it's actually much simpler for montoring
+// software if we just exit when an unexpected panic happens.
+func HandleCrash(additionalHandlers ...func(interface{})) {
+	if r := recover(); r != nil {
+		for _, fn := range PanicHandlers {
+			fn(r)
+		}
+		for _, fn := range additionalHandlers {
+			fn(r)
+		}
+		if ReallyCrash {
+			// Actually proceed to panic.
+			panic(r)
+		}
+	}
+}
+
+// logPanic logs the caller tree when a panic occurs.
+func logPanic(r interface{}) {
+	callers := getCallers(r)
+	glog.Errorf("Observed a panic: %#v (%v)\n%v", r, r, callers)
+}
+
+func getCallers(r interface{}) string {
+	callers := ""
+	for i := 0; true; i++ {
+		_, file, line, ok := runtime.Caller(i)
+		if !ok {
+			break
+		}
+		callers = callers + fmt.Sprintf("%v:%v\n", file, line)
+	}
+
+	return callers
+}
+
+// ErrorHandlers is a list of functions which will be invoked when an unreturnable
+// error occurs.
+// TODO(lavalamp): for testability, this and the below HandleError function
+// should be packaged up into a testable and reusable object.
+var ErrorHandlers = []func(error){
+	logError,
+	(&rudimentaryErrorBackoff{
+		lastErrorTime: time.Now(),
+		// 1ms was the number folks were able to stomach as a global rate limit.
+		// If you need to log errors more than 1000 times a second you
+		// should probably consider fixing your code instead. :)
+		minPeriod: time.Millisecond,
+	}).OnError,
+}
+
+// HandlerError is a method to invoke when a non-user facing piece of code cannot
+// return an error and needs to indicate it has been ignored. Invoking this method
+// is preferable to logging the error - the default behavior is to log but the
+// errors may be sent to a remote server for analysis.
+func HandleError(err error) {
+	// this is sometimes called with a nil error.  We probably shouldn't fail and should do nothing instead
+	if err == nil {
+		return
+	}
+
+	for _, fn := range ErrorHandlers {
+		fn(err)
+	}
+}
+
+// logError prints an error with the call stack of the location it was reported
+func logError(err error) {
+	glog.ErrorDepth(2, err)
+}
+
+type rudimentaryErrorBackoff struct {
+	minPeriod time.Duration // immutable
+	// TODO(lavalamp): use the clock for testability. Need to move that
+	// package for that to be accessible here.
+	lastErrorTimeLock sync.Mutex
+	lastErrorTime     time.Time
+}
+
+// OnError will block if it is called more often than the embedded period time.
+// This will prevent overly tight hot error loops.
+func (r *rudimentaryErrorBackoff) OnError(error) {
+	r.lastErrorTimeLock.Lock()
+	defer r.lastErrorTimeLock.Unlock()
+	d := time.Since(r.lastErrorTime)
+	if d < r.minPeriod && d >= 0 {
+		// If the time moves backwards for any reason, do nothing
+		// TODO: remove check "d >= 0" after go 1.8 is no longer supported
+		time.Sleep(r.minPeriod - d)
+	}
+	r.lastErrorTime = time.Now()
+}
+
+// GetCaller returns the caller of the function that calls it.
+func GetCaller() string {
+	var pc [1]uintptr
+	runtime.Callers(3, pc[:])
+	f := runtime.FuncForPC(pc[0])
+	if f == nil {
+		return fmt.Sprintf("Unable to find caller")
+	}
+	return f.Name()
+}
+
+// RecoverFromPanic replaces the specified error with an error containing the
+// original error, and  the call tree when a panic occurs. This enables error
+// handlers to handle errors and panics the same way.
+func RecoverFromPanic(err *error) {
+	if r := recover(); r != nil {
+		callers := getCallers(r)
+
+		*err = fmt.Errorf(
+			"recovered from panic %q. (err=%v) Call stack:\n%v",
+			r,
+			*err,
+			callers)
+	}
+}