--- /dev/null
+From 8d6f2e3fe8851b581309da25fc4c32f8be675932 Mon Sep 17 00:00:00 2001
+From: Brian Goff <cpuguy83@gmail.com>
+Date: Mon, 11 Jul 2016 16:31:42 -0400
+Subject: [PATCH] Fix issues with tailing rotated jsonlog file
+
+Fixes a race where the log reader would get events for both an actual
+rotation as we from fsnotify (`fsnotify.Rename`).
+This issue becomes extremely apparent when rotations are fast, for
+example:
+
+```
+$ docker run -d --name test --log-opt max-size=1 --log-opt max-file=2
+busybox sh -c 'while true; do echo hello; usleep 100000; done'
+```
+
+With this change the log reader for jsonlogs can handle rotations that
+happen as above.
+
+Instead of listening for both fs events AND rotation events
+simultaneously, potentially meaning we see 2 rotations for only a single
+rotation due to channel buffering, only listen for fs events (like
+`Rename`) and then wait to be notified about rotation by the logger.
+This makes sure that we don't see 2 rotations for 1, and that we don't
+start trying to read until the logger is actually ready for us to.
+
+Signed-off-by: Brian Goff <cpuguy83@gmail.com>
+
+This commit is pending upstream commit fixing broken log tailing. The
+original commit can be found in the PR here:
+
+ - https://github.com/docker/docker/pull/24514
+
+Signed-off-by: Christian Stewart <christian@paral.in>
+---
+ daemon/logger/jsonfilelog/read.go | 180 +++++++++++++++++++++++++-------------
+ 1 file changed, 119 insertions(+), 61 deletions(-)
+
+diff --git a/daemon/logger/jsonfilelog/read.go b/daemon/logger/jsonfilelog/read.go
+index bea83dd..0cb44af 100644
+--- a/daemon/logger/jsonfilelog/read.go
++++ b/daemon/logger/jsonfilelog/read.go
+@@ -3,11 +3,14 @@ package jsonfilelog
+ import (
+ "bytes"
+ "encoding/json"
++ "errors"
+ "fmt"
+ "io"
+ "os"
+ "time"
+
++ "gopkg.in/fsnotify.v1"
++
+ "github.com/Sirupsen/logrus"
+ "github.com/docker/docker/daemon/logger"
+ "github.com/docker/docker/pkg/filenotify"
+@@ -44,6 +47,10 @@ func (l *JSONFileLogger) ReadLogs(config logger.ReadConfig) *logger.LogWatcher {
+ func (l *JSONFileLogger) readLogs(logWatcher *logger.LogWatcher, config logger.ReadConfig) {
+ defer close(logWatcher.Msg)
+
++ // lock so the read stream doesn't get corrupted do to rotations or other log data written while we read
++ // This will block writes!!!
++ l.mu.Lock()
++
+ pth := l.writer.LogPath()
+ var files []io.ReadSeeker
+ for i := l.writer.MaxFiles(); i > 1; i-- {
+@@ -61,6 +68,7 @@ func (l *JSONFileLogger) readLogs(logWatcher *logger.LogWatcher, config logger.R
+ latestFile, err := os.Open(pth)
+ if err != nil {
+ logWatcher.Err <- err
++ l.mu.Unlock()
+ return
+ }
+
+@@ -80,6 +88,7 @@ func (l *JSONFileLogger) readLogs(logWatcher *logger.LogWatcher, config logger.R
+ if err := latestFile.Close(); err != nil {
+ logrus.Errorf("Error closing file: %v", err)
+ }
++ l.mu.Unlock()
+ return
+ }
+
+@@ -87,7 +96,6 @@ func (l *JSONFileLogger) readLogs(logWatcher *logger.LogWatcher, config logger.R
+ latestFile.Seek(0, os.SEEK_END)
+ }
+
+- l.mu.Lock()
+ l.readers[logWatcher] = struct{}{}
+ l.mu.Unlock()
+
+@@ -128,92 +136,142 @@ func tailFile(f io.ReadSeeker, logWatcher *logger.LogWatcher, tail int, since ti
+ }
+ }
+
++func watchFile(name string) (filenotify.FileWatcher, error) {
++ fileWatcher, err := filenotify.New()
++ if err != nil {
++ return nil, err
++ }
++
++ if err := fileWatcher.Add(name); err != nil {
++ logrus.WithField("logger", "json-file").Warnf("falling back to file poller due to error: %v", err)
++ fileWatcher.Close()
++ fileWatcher = filenotify.NewPollingWatcher()
++
++ if err := fileWatcher.Add(name); err != nil {
++ fileWatcher.Close()
++ logrus.Debugf("error watching log file for modifications: %v", err)
++ return nil, err
++ }
++ }
++ return fileWatcher, nil
++}
++
+ func followLogs(f *os.File, logWatcher *logger.LogWatcher, notifyRotate chan interface{}, since time.Time) {
+ dec := json.NewDecoder(f)
+ l := &jsonlog.JSONLog{}
+
+- fileWatcher, err := filenotify.New()
++ name := f.Name()
++ fileWatcher, err := watchFile(name)
+ if err != nil {
+ logWatcher.Err <- err
++ return
+ }
+ defer func() {
+ f.Close()
+ fileWatcher.Close()
+ }()
+- name := f.Name()
+
+- if err := fileWatcher.Add(name); err != nil {
+- logrus.WithField("logger", "json-file").Warnf("falling back to file poller due to error: %v", err)
+- fileWatcher.Close()
+- fileWatcher = filenotify.NewPollingWatcher()
++ var retries int
++ handleRotate := func() error {
++ f.Close()
++ fileWatcher.Remove(name)
+
++ // retry when the file doesn't exist
++ for retries := 0; retries <= 5; retries++ {
++ f, err = os.Open(name)
++ if err == nil || !os.IsNotExist(err) {
++ break
++ }
++ }
++ if err != nil {
++ return err
++ }
+ if err := fileWatcher.Add(name); err != nil {
+- logrus.Debugf("error watching log file for modifications: %v", err)
+- logWatcher.Err <- err
+- return
++ return err
+ }
++ dec = json.NewDecoder(f)
++ return nil
+ }
+
+- var retries int
+- for {
+- msg, err := decodeLogLine(dec, l)
+- if err != nil {
+- if err != io.EOF {
+- // try again because this shouldn't happen
+- if _, ok := err.(*json.SyntaxError); ok && retries <= maxJSONDecodeRetry {
+- dec = json.NewDecoder(f)
+- retries++
+- continue
++ errRetry := errors.New("retry")
++ errDone := errors.New("done")
++ waitRead := func() error {
++ select {
++ case e := <-fileWatcher.Events():
++ switch e.Op {
++ case fsnotify.Write:
++ dec = json.NewDecoder(f)
++ return nil
++ case fsnotify.Rename, fsnotify.Remove:
++ <-notifyRotate
++ if err := handleRotate(); err != nil {
++ return err
+ }
+-
+- // io.ErrUnexpectedEOF is returned from json.Decoder when there is
+- // remaining data in the parser's buffer while an io.EOF occurs.
+- // If the json logger writes a partial json log entry to the disk
+- // while at the same time the decoder tries to decode it, the race condition happens.
+- if err == io.ErrUnexpectedEOF && retries <= maxJSONDecodeRetry {
+- reader := io.MultiReader(dec.Buffered(), f)
+- dec = json.NewDecoder(reader)
+- retries++
+- continue
++ return nil
++ }
++ return errRetry
++ case err := <-fileWatcher.Errors():
++ logrus.Debug("logger got error watching file: %v", err)
++ // Something happened, let's try and stay alive and create a new watcher
++ if retries <= 5 {
++ fileWatcher, err = watchFile(name)
++ if err != nil {
++ return err
+ }
+-
+- return
++ retries++
++ return errRetry
+ }
++ return err
++ case <-logWatcher.WatchClose():
++ fileWatcher.Remove(name)
++ return errDone
++ }
++ }
+
+- select {
+- case <-fileWatcher.Events():
+- dec = json.NewDecoder(f)
+- continue
+- case <-fileWatcher.Errors():
+- logWatcher.Err <- err
+- return
+- case <-logWatcher.WatchClose():
+- fileWatcher.Remove(name)
+- return
+- case <-notifyRotate:
+- f.Close()
+- fileWatcher.Remove(name)
+-
+- // retry when the file doesn't exist
+- for retries := 0; retries <= 5; retries++ {
+- f, err = os.Open(name)
+- if err == nil || !os.IsNotExist(err) {
+- break
+- }
++ handleDecodeErr := func(err error) error {
++ if err == io.EOF {
++ for err := waitRead(); err != nil; {
++ if err == errRetry {
++ // retry the waitRead
++ continue
+ }
++ return err
++ }
++ return nil
++ }
++ // try again because this shouldn't happen
++ if _, ok := err.(*json.SyntaxError); ok && retries <= maxJSONDecodeRetry {
++ dec = json.NewDecoder(f)
++ retries++
++ return nil
++ }
++ // io.ErrUnexpectedEOF is returned from json.Decoder when there is
++ // remaining data in the parser's buffer while an io.EOF occurs.
++ // If the json logger writes a partial json log entry to the disk
++ // while at the same time the decoder tries to decode it, the race condition happens.
++ if err == io.ErrUnexpectedEOF && retries <= maxJSONDecodeRetry {
++ reader := io.MultiReader(dec.Buffered(), f)
++ dec = json.NewDecoder(reader)
++ retries++
++ return nil
++ }
++ return err
++ }
+
+- if err = fileWatcher.Add(name); err != nil {
+- logWatcher.Err <- err
+- return
+- }
+- if err != nil {
+- logWatcher.Err <- err
++ // main loop
++ for {
++ msg, err := decodeLogLine(dec, l)
++ if err != nil {
++ if err := handleDecodeErr(err); err != nil {
++ if err == errDone {
+ return
+ }
+-
+- dec = json.NewDecoder(f)
+- continue
++ // we got an unrecoverable error, so return
++ logWatcher.Err <- err
++ return
+ }
++ // ready to try again
++ continue
+ }
+
+ retries = 0 // reset retries since we've succeeded
+--
+2.7.3
+
--- /dev/null
+config BR2_PACKAGE_DOCKER_ENGINE
+ bool "docker-engine"
+ depends on BR2_PACKAGE_HOST_GO_ARCH_SUPPORTS
+ depends on BR2_PACKAGE_HOST_GO_CGO_LINKING_SUPPORTS
+ depends on BR2_TOOLCHAIN_HAS_THREADS
+ help
+ Docker is a platform to build, ship,
+ and run applications as lightweight containers.
+
+ https://github.com/docker/docker
+
+if BR2_PACKAGE_DOCKER_ENGINE
+
+config BR2_PACKAGE_DOCKER_ENGINE_DAEMON
+ bool "docker daemon"
+ depends on BR2_USE_WCHAR # docker-containerd
+ select BR2_PACKAGE_DOCKER_CONTAINERD # runtime dependency
+ select BR2_PACKAGE_SQLITE # runtime dependency
+ default y
+ help
+ Build the Docker system daemon.
+ If not selected, will build client only.
+
+config BR2_PACKAGE_DOCKER_ENGINE_EXPERIMENTAL
+ bool "build experimental features"
+
+if BR2_PACKAGE_DOCKER_ENGINE_DAEMON
+
+config BR2_PACKAGE_DOCKER_ENGINE_DRIVER_BTRFS
+ bool "btrfs filesystem driver"
+ depends on BR2_USE_WCHAR # btrfs-progs
+ depends on BR2_USE_MMU # btrfs-progs
+ depends on BR2_TOOLCHAIN_HAS_THREADS # btrfs-progs
+ select BR2_PACKAGE_BTRFS_PROGS
+ help
+ Build the btrfs filesystem driver for Docker.
+
+config BR2_PACKAGE_DOCKER_ENGINE_DRIVER_DEVICEMAPPER
+ bool "devicemapper filesystem driver"
+ depends on BR2_TOOLCHAIN_HAS_THREADS # lvm2
+ depends on BR2_USE_MMU # lvm2
+ depends on !BR2_STATIC_LIBS # lvm2
+ select BR2_PACKAGE_LVM2
+ select BR2_PACKAGE_LVM2_APP_LIBRARY
+ help
+ Build the devicemapper filesystem driver for Docker.
+
+config BR2_PACKAGE_DOCKER_ENGINE_DRIVER_VFS
+ bool "vfs filesystem driver"
+ depends on BR2_USE_WCHAR # gvfs
+ depends on BR2_USE_MMU # gvfs
+ depends on BR2_TOOLCHAIN_HAS_THREADS # gvfs
+ select BR2_PACKAGE_GVFS
+ help
+ Build the vfs filesystem driver for Docker.
+
+endif
+
+endif
+
+comment "docker-engine needs a toolchain w/ threads"
+ depends on BR2_PACKAGE_HOST_GO_ARCH_SUPPORTS
+ depends on BR2_PACKAGE_HOST_GO_CGO_LINKING_SUPPORTS
+ depends on !BR2_TOOLCHAIN_HAS_THREADS
--- /dev/null
+################################################################################
+#
+# docker-engine
+#
+################################################################################
+
+DOCKER_ENGINE_VERSION = v1.12.0-rc4
+DOCKER_ENGINE_SITE = $(call github,docker,docker,$(DOCKER_ENGINE_VERSION))
+
+DOCKER_ENGINE_LICENSE = Apache-2.0
+DOCKER_ENGINE_LICENSE_FILES = LICENSE
+
+DOCKER_ENGINE_DEPENDENCIES = host-go
+
+DOCKER_ENGINE_GOPATH = "$(@D)/vendor"
+DOCKER_ENGINE_MAKE_ENV = $(HOST_GO_TARGET_ENV) \
+ CGO_ENABLED=1 \
+ CGO_NO_EMULATION=1 \
+ GOBIN="$(@D)/bin" \
+ GOPATH="$(DOCKER_ENGINE_GOPATH)"
+
+DOCKER_ENGINE_GLDFLAGS = \
+ -X main.GitCommit=$(DOCKER_ENGINE_VERSION) \
+ -X main.Version=$(DOCKER_ENGINE_VERSION)
+
+ifeq ($(BR2_STATIC_LIBS),y)
+DOCKER_ENGINE_GLDFLAGS += -extldflags '-static'
+endif
+
+DOCKER_ENGINE_BUILD_TAGS = cgo exclude_graphdriver_zfs autogen
+DOCKER_ENGINE_BUILD_TARGETS = docker
+
+ifeq ($(BR2_PACKAGE_LIBSECCOMP),y)
+DOCKER_ENGINE_BUILD_TAGS += seccomp
+DOCKER_ENGINE_DEPENDENCIES += libseccomp
+endif
+
+ifeq ($(BR2_PACKAGE_DOCKER_ENGINE_DAEMON),y)
+DOCKER_ENGINE_BUILD_TAGS += daemon
+DOCKER_ENGINE_BUILD_TARGETS += dockerd
+endif
+
+ifeq ($(BR2_PACKAGE_DOCKER_ENGINE_EXPERIMENTAL),y)
+DOCKER_ENGINE_BUILD_TAGS += experimental
+endif
+
+ifeq ($(BR2_PACKAGE_DOCKER_ENGINE_DRIVER_BTRFS),y)
+DOCKER_ENGINE_DEPENDENCIES += btrfs-progs
+else
+DOCKER_ENGINE_BUILD_TAGS += exclude_graphdriver_btrfs
+endif
+
+ifeq ($(BR2_PACKAGE_DOCKER_ENGINE_DRIVER_DEVICEMAPPER),y)
+DOCKER_ENGINE_DEPENDENCIES += lvm2
+else
+DOCKER_ENGINE_BUILD_TAGS += exclude_graphdriver_devicemapper
+endif
+
+ifeq ($(BR2_PACKAGE_DOCKER_ENGINE_DRIVER_VFS),y)
+DOCKER_ENGINE_DEPENDENCIES += gvfs
+else
+DOCKER_ENGINE_BUILD_TAGS += exclude_graphdriver_vfs
+endif
+
+define DOCKER_ENGINE_CONFIGURE_CMDS
+ ln -fs $(@D) $(DOCKER_ENGINE_GOPATH)/src/github.com/docker/docker
+ cd $(@D) && \
+ GITCOMMIT="unknown" BUILDTIME="$$(date)" VERSION="$(DOCKER_ENGINE_VERSION)" \
+ bash ./hack/make/.go-autogen
+endef
+
+ifeq ($(BR2_PACKAGE_DOCKER_ENGINE_DAEMON),y)
+
+define DOCKER_ENGINE_INSTALL_INIT_SYSTEMD
+ $(INSTALL) -D -m 0644 $(@D)/contrib/init/systemd/docker.service \
+ $(TARGET_DIR)/usr/lib/systemd/system/docker.service
+ $(INSTALL) -D -m 0644 $(@D)/contrib/init/systemd/docker.socket \
+ $(TARGET_DIR)/usr/lib/systemd/system/docker.socket
+ mkdir -p $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants/
+ ln -fs ../../../../usr/lib/systemd/system/docker.service \
+ $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants/docker.service
+endef
+
+define DOCKER_ENGINE_USERS
+ - - docker -1 * - - - Docker Application Container Framework
+endef
+
+endif
+
+define DOCKER_ENGINE_BUILD_CMDS
+ $(foreach target,$(DOCKER_ENGINE_BUILD_TARGETS), \
+ cd $(@D); $(DOCKER_ENGINE_MAKE_ENV) \
+ $(HOST_DIR)/usr/bin/go build -v \
+ -o $(@D)/bin/$(target) \
+ -tags "$(DOCKER_ENGINE_BUILD_TAGS)" \
+ -ldflags "$(DOCKER_ENGINE_GLDFLAGS)" \
+ ./cmd/$(target)
+ )
+endef
+
+define DOCKER_ENGINE_INSTALL_TARGET_CMDS
+ $(foreach target,$(DOCKER_ENGINE_BUILD_TARGETS), \
+ $(INSTALL) -D -m 0755 $(@D)/bin/$(target) $(TARGET_DIR)/usr/bin/$(target)
+ )
+endef
+
+$(eval $(generic-package))
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