From bcbb187bef71c2b1a6b6ed2e75b9def79750fc2c Mon Sep 17 00:00:00 2001 From: Saxon Nelson-Milton Date: Tue, 13 Jun 2023 21:01:47 +0930 Subject: [PATCH] vidforward: add config file watcher This change adds a file watcher and then uses this file watcher to perform updates based on changes in a configuration file. This configuration file contains logging parameters for the time being in the hope that it will help with debugging. Testing was also added for this functionality. --- cmd/vidforward/main.go | 58 +++++++++++++++ cmd/vidforward/watcher.go | 79 +++++++++++++++++++++ cmd/vidforward/watcher_test.go | 124 +++++++++++++++++++++++++++++++++ go.mod | 5 +- go.sum | 8 ++- 5 files changed, 271 insertions(+), 3 deletions(-) create mode 100644 cmd/vidforward/watcher.go create mode 100644 cmd/vidforward/watcher_test.go diff --git a/cmd/vidforward/main.go b/cmd/vidforward/main.go index 8b0994fe..814462f4 100644 --- a/cmd/vidforward/main.go +++ b/cmd/vidforward/main.go @@ -32,6 +32,7 @@ import ( "flag" "fmt" "io" + "io/ioutil" "net" "net/http" "os" @@ -46,6 +47,10 @@ import ( "gopkg.in/natefinch/lumberjack.v2" ) +// This is the path to the vidforward configuration. +// This contains parameters such as log level and logging filters. +const configFileName = "/etc/vidforward/config.json" + // Server defaults. const ( defaultPort = "8080" @@ -125,6 +130,49 @@ func terminationCallback(m *broadcastManager) func() { } } +// loadConfig loads the vidforward configuration file. This primarily concerns logging +// configuration for the time being, with the intended use case of debugging. +func (m *broadcastManager) loadConfig() error { + m.mu.Lock() + defer m.mu.Unlock() + + data, err := ioutil.ReadFile(configFileName) + if err != nil { + return fmt.Errorf("could not read config file: %w", err) + } + + var cfg struct { + LogLevel string `json:"LogLevel"` + LogSuppress bool `json:"LogSuppress"` + LogCallerFilters []string `json:"LogCallerFilters"` + } + + if err = json.Unmarshal(data, &cfg); err != nil { + return fmt.Errorf("could not unmarshal config file: %w", err) + } + + m.log.(*logging.JSONLogger).SetLevel(map[string]int8{ + "debug": logging.Debug, + "info": logging.Info, + "warning": logging.Warning, + "error": logging.Error, + "fatal": logging.Fatal, + }[cfg.LogLevel]) + m.log.(*logging.JSONLogger).SetSuppress(cfg.LogSuppress) + m.log.(*logging.JSONLogger).SetCallerFilters(cfg.LogCallerFilters...) + + return nil +} + +// This is a callback that can be used by file watchers to reload the config. +func (m *broadcastManager) onConfigChange() { + err := m.loadConfig() + if err != nil { + m.log.Error("could not load config", "error", err) + return + } +} + // recvHandler handles recv requests for video forwarding. The MAC is firstly // checked to ensure it is "active" i.e. should be sending data, and then the // video is extracted from the request body and provided to the revid pipeline @@ -413,6 +461,16 @@ func main() { log.Warning("could not load previous state", "error", err) } + // Try to load the config file. + err = m.loadConfig() + if err != nil { + log.Warning("could not load config file", "error", err) + } + + // Set up a file watcher to watch the config file. This will allow us + // to perform updates to configuration while the service is running. + watchFile(configFileName, m.onConfigChange, log) + http.HandleFunc("/recv", m.recv) http.HandleFunc("/control", m.control) http.HandleFunc("/slate", m.slate) diff --git a/cmd/vidforward/watcher.go b/cmd/vidforward/watcher.go new file mode 100644 index 00000000..37d85182 --- /dev/null +++ b/cmd/vidforward/watcher.go @@ -0,0 +1,79 @@ +/* +DESCRIPTION + + watcher.go provides a tool for watching a file for modifications and + performing an action when the file is modified. + +AUTHORS + + Saxon A. Nelson-Milton + +LICENSE + + Copyright (C) 2022 the Australian Ocean Lab (AusOcean) + + It is free software: you can redistribute it and/or modify them + under the terms of the GNU General Public License as published by the + Free Software Foundation, either version 3 of the License, or (at your + option) any later version. + + It is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License + along with revid in gpl.txt. If not, see http://www.gnu.org/licenses. +*/ + +package main + +import ( + "fmt" + "path" + + "bitbucket.org/ausocean/utils/logging" + "github.com/fsnotify/fsnotify" +) + +// watchFile watches a file for modifications and calls onWrite when the file +// is modified. Technically, the directory is watched instead of the file. +// This is because watching the file itself will cause problems if changes +// are done atomically. +// See fsnotify documentation: +// https://godocs.io/github.com/fsnotify/fsnotify#hdr-Watching_files +func watchFile(file string, onWrite func(), l logging.Logger) error { + watcher, err := fsnotify.NewWatcher() + if err != nil { + return fmt.Errorf("could not create watcher: %w", err) + } + + go func() { + for { + select { + case event, ok := <-watcher.Events: + if !ok { + l.Warning("watcher events chan closed, terminating") + return + } + if event.Op&fsnotify.Write == fsnotify.Write && event.Name == file { + l.Info("file modification event", "file", file) + onWrite() + } + case err, ok := <-watcher.Errors: + if !ok { + l.Warning("watcher error chan closed, terminating") + return + } + l.Error("file watcher error", "error", err) + } + } + }() + + // Watch the directory over the file. + err = watcher.Add(path.Dir(file)) + if err != nil { + return fmt.Errorf("could not add file %s to watcher: %w", file, err) + } + return nil +} diff --git a/cmd/vidforward/watcher_test.go b/cmd/vidforward/watcher_test.go new file mode 100644 index 00000000..240478e1 --- /dev/null +++ b/cmd/vidforward/watcher_test.go @@ -0,0 +1,124 @@ +package main + +import ( + "io/ioutil" + "os" + "path/filepath" + "testing" + "time" + + "bitbucket.org/ausocean/utils/logging" +) + +// Delay between changing a file and the file watcher picking up the change. +const watchTimeAllowance = 1 * time.Second + +// TestWatchFile tests the watchFile function. It creates a temporary file, +// watches it, writes to it, and checks if the onWrite function was called. +func TestWatchFile(t *testing.T) { + tmpFile, err := ioutil.TempFile("", "example") + if err != nil { + t.Fatalf("could not create temporary file: %v", err) + } + defer os.Remove(tmpFile.Name()) + + // We'll check this to see if the onWrite function was called. + called := false + + err = watchFile(tmpFile.Name(), func() { + called = true + }, (*logging.TestLogger)(t)) + if err != nil { + t.Fatalf("watchFile failed: %v", err) + } + + if _, err := tmpFile.Write([]byte("hello world")); err != nil { + t.Fatalf("could not write to temporary file: %v", err) + } + if err := tmpFile.Close(); err != nil { + t.Fatalf("could not close temporary file: %v", err) + } + + // Allow some time for the file watcher to pick up the change. + time.Sleep(watchTimeAllowance) + + if !called { + t.Errorf("onWrite was not called after modifying the file") + } +} + +// TestWatchFileFileNotExistYet tests the watchFile function in the case +// that the file to be watched does not exist on the first call to watchFile. +// It creates a temporary directory, watches a file in that directory, creates +// and writes to the file, and checks if the onWrite function was called. +func TestWatchFileFileNotExistYet(t *testing.T) { + // Create a temporary directory. + tmpDir, err := ioutil.TempDir("", "example") + if err != nil { + t.Fatalf("could not create temporary directory: %v", err) + } + defer os.Remove(tmpDir) // clean up + + // File that does not exist yet but will be created in the temporary directory. + fileName := filepath.Join(tmpDir, "testfile") + + called := false + err = watchFile(fileName, func() { + called = true + }, (*logging.TestLogger)(t)) + if err != nil { + t.Fatalf("watchFile failed: %v", err) + } + + // Create and write to the file. + err = ioutil.WriteFile(fileName, []byte("hello world"), 0666) + if err != nil { + t.Fatalf("could not write to file: %v", err) + } + + // Allow some time for the file watcher to pick up the change. + time.Sleep(watchTimeAllowance) + + if !called { + t.Errorf("onWrite was not called after creating and modifying the file") + } +} + +// TestWatchFileMultipleChanges tests the watchFile function in the case +// that the file to be watched is modified multiple times. It creates a +// temporary file, watches it, writes to it twice, and checks if the onWrite +// function was called twice. +func TestWatchFileMultipleChanges(t *testing.T) { + tmpfile, err := ioutil.TempFile("", "example") + if err != nil { + t.Fatalf("could not create temporary file: %v", err) + } + defer os.Remove(tmpfile.Name()) + + // We'll count how many times onWrite was called. + calledCount := 0 + + err = watchFile(tmpfile.Name(), func() { + calledCount++ + }, (*logging.TestLogger)(t)) + if err != nil { + t.Fatalf("watchFile failed: %v", err) + } + + // Write to the file twice. + for i := 0; i < 2; i++ { + if _, err := tmpfile.Write([]byte("hello world")); err != nil { + t.Fatalf("could not write to temporary file: %v", err) + } + if err := tmpfile.Sync(); err != nil { + t.Fatalf("could not sync temporary file: %v", err) + } + + // Allow some time for the file watcher to pick up the change. + time.Sleep(watchTimeAllowance) + } + + if calledCount != 2 { + t.Errorf("onWrite was not called the expected number of times after modifying the file") + } +} diff --git a/go.mod b/go.mod index 83ed2ab3..de8e1ae7 100644 --- a/go.mod +++ b/go.mod @@ -4,7 +4,7 @@ go 1.18 require ( bitbucket.org/ausocean/iot v1.4.1 - bitbucket.org/ausocean/utils v1.3.2 + bitbucket.org/ausocean/utils v1.4.0 github.com/Comcast/gots v0.0.0-20190305015453-8d56e473f0f7 github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf github.com/go-audio/audio v0.0.0-20181013203223-7b2a6ca21480 @@ -22,6 +22,8 @@ require ( gopkg.in/natefinch/lumberjack.v2 v2.0.0 ) +require github.com/fsnotify/fsnotify v1.6.0 + require ( github.com/ajstarks/svgo v0.0.0-20180226025133-644b8db467af // indirect github.com/fogleman/gg v1.3.0 // indirect @@ -35,4 +37,5 @@ require ( go.uber.org/multierr v1.1.0 // indirect go.uber.org/zap v1.10.0 // indirect golang.org/x/image v0.0.0-20210216034530-4410531fe030 // indirect + golang.org/x/sys v0.0.0-20220908164124-27713097b956 // indirect ) diff --git a/go.sum b/go.sum index 63c6f33f..05e1cadf 100644 --- a/go.sum +++ b/go.sum @@ -3,8 +3,8 @@ bitbucket.org/ausocean/iot v1.4.1 h1:PcRu9dS5CbKyw1FZjEc4MR9CQ+ku9MkH9ZjA0f6Mm1c bitbucket.org/ausocean/iot v1.4.1/go.mod h1:NbEg2PvYSHDdUsy5eMmihBySpWfqaHiMdspQDZdDe8o= bitbucket.org/ausocean/utils v1.2.11/go.mod h1:uXzX9z3PLemyURTMWRhVI8uLhPX4uuvaaO85v2hcob8= bitbucket.org/ausocean/utils v1.3.0/go.mod h1:yWsulKjbBgwL17/w55MQ6cIT9jmNeOkwpd2gUIxAcIY= -bitbucket.org/ausocean/utils v1.3.2 h1:U+jNixVPH1Ih0QpOckI4djhEc/T6FAzt9znADRcJ07s= -bitbucket.org/ausocean/utils v1.3.2/go.mod h1:XgvCH4DQLCd6NYMzsSqwhHmPr+qzYks5M8IDpdNnZiU= +bitbucket.org/ausocean/utils v1.4.0 h1:ceNRscC49fAVY9tIOAN3Jyg7g+A9JTKjqgxEGb7A+9E= +bitbucket.org/ausocean/utils v1.4.0/go.mod h1:XgvCH4DQLCd6NYMzsSqwhHmPr+qzYks5M8IDpdNnZiU= dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU= gioui.org v0.0.0-20210308172011-57750fc8a0a6/go.mod h1:RSH6KIUZ0p2xy5zHDxgAM4zumjgTw83q2ge/PI+yyw8= github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ= @@ -36,6 +36,8 @@ github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs github.com/fogleman/gg v1.2.1-0.20190220221249-0403632d5b90/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k= github.com/fogleman/gg v1.3.0 h1:/7zJX8F6AaYQc57WQCyN9cAIz+4bCJGO9B+dyW29am8= github.com/fogleman/gg v1.3.0/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k= +github.com/fsnotify/fsnotify v1.6.0 h1:n+5WquG0fcWoWp6xPWfHdbskMCQaFnG6PfBrh1Ky4HY= +github.com/fsnotify/fsnotify v1.6.0/go.mod h1:sl3t1tCWJFWoRz9R8WJCbQihKKwmorjAbSClcnxKAGw= github.com/go-audio/aiff v0.0.0-20180403003018-6c3a8a6aff12/go.mod h1:AMSAp6W1zd0koOdX6QDgGIuBDTUvLa2SLQtm7d9eM3c= github.com/go-audio/audio v0.0.0-20180206231410-b697a35b5608/go.mod h1:6uAu0+H2lHkwdGsAY+j2wHPNPpPoeg5AaEFh9FlA+Zs= github.com/go-audio/audio v0.0.0-20181013203223-7b2a6ca21480 h1:4sGU+UABMMsRJyD+Y2yzMYxq0GJFUsRRESI0P1gZ2ig= @@ -141,6 +143,8 @@ golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7w golang.org/x/sys v0.0.0-20210304124612-50617c2ba197/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg= golang.org/x/sys v0.0.0-20210909193231-528a39cd75f3/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg= +golang.org/x/sys v0.0.0-20220908164124-27713097b956 h1:XeJjHH1KiLpKGb6lvMiksZ9l0fVUh+AmGcm0nOMEBOY= +golang.org/x/sys v0.0.0-20220908164124-27713097b956/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg= golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo= golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ= golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=