Merging other languages
This commit is contained in:
James Miranda
501
en/13.4.md
501
en/13.4.md
@@ -1,248 +1,253 @@
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# 13.4 日志和配置设计
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## 日志和配置的重要性
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前面已经介绍过日志在我们程序开发中起着很重要的作用，通过日志我们可以记录调试我们的信息，当初介绍过一个日志系统seelog，根据不同的level输出不同的日志，这个对于程序开发和程序部署来说至关重要。我们可以在程序开发中设置level低一点，部署的时候把level设置高，这样我们开发中的调试信息可以屏蔽掉。
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配置模块对于应用部署牵涉到服务器不同的一些配置信息非常有用，例如一些数据库配置信息、监听端口、监听地址等都是可以通过配置文件来配置，这样我们的应用程序就具有很强的灵活性，可以通过配置文件的配置部署在不同的机器上，可以连接不同的数据库之类的。
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## beego的日志设计
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beego的日志设计部署思路来自于seelog，根据不同的level来记录日志，但是beego设计的日志系统比较轻量级，采用了系统的log.Logger接口，默认输出到os.Stdout,用户可以实现这个接口然后通过beego.SetLogger设置自定义的输出，详细的实现如下所示：
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// Log levels to control the logging output.
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const (
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LevelTrace = iota
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LevelDebug
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LevelInfo
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LevelWarning
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LevelError
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LevelCritical
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)
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// logLevel controls the global log level used by the logger.
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var level = LevelTrace
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// LogLevel returns the global log level and can be used in
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// own implementations of the logger interface.
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func Level() int {
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return level
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}
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// SetLogLevel sets the global log level used by the simple
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// logger.
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func SetLevel(l int) {
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level = l
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}
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上面这一段实现了日志系统的日志分级，默认的级别是Trace，用户通过SetLevel可以设置不同的分级。
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// logger references the used application logger.
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var BeeLogger = log.New(os.Stdout, "", log.Ldate|log.Ltime)
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// SetLogger sets a new logger.
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func SetLogger(l *log.Logger) {
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BeeLogger = l
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}
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// Trace logs a message at trace level.
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func Trace(v ...interface{}) {
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if level <= LevelTrace {
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BeeLogger.Printf("[T] %v\n", v)
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}
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}
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// Debug logs a message at debug level.
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func Debug(v ...interface{}) {
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if level <= LevelDebug {
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BeeLogger.Printf("[D] %v\n", v)
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}
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}
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// Info logs a message at info level.
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func Info(v ...interface{}) {
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if level <= LevelInfo {
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BeeLogger.Printf("[I] %v\n", v)
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}
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}
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// Warning logs a message at warning level.
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func Warn(v ...interface{}) {
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if level <= LevelWarning {
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BeeLogger.Printf("[W] %v\n", v)
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}
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}
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// Error logs a message at error level.
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func Error(v ...interface{}) {
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if level <= LevelError {
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BeeLogger.Printf("[E] %v\n", v)
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}
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}
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// Critical logs a message at critical level.
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func Critical(v ...interface{}) {
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if level <= LevelCritical {
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BeeLogger.Printf("[C] %v\n", v)
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}
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}
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上面这一段代码默认初始化了一个BeeLogger对象，默认输出到os.Stdout，用户可以通过beego.SetLogger来设置实现了logger的接口输出。这里面实现了六个函数：
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- Trace（一般的记录信息，举例如下：）
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- "Entered parse function validation block"
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- "Validation: entered second 'if'"
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- "Dictionary 'Dict' is empty. Using default value"
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- Debug（调试信息，举例如下：）
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- "Web page requested: http://somesite.com Params='...'"
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- "Response generated. Response size: 10000. Sending."
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- "New file received. Type:PNG Size:20000"
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- Info（打印信息，举例如下：）
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- "Web server restarted"
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- "Hourly statistics: Requested pages: 12345 Errors: 123 ..."
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- "Service paused. Waiting for 'resume' call"
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- Warn（警告信息，举例如下：）
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- "Cache corrupted for file='test.file'. Reading from back-end"
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- "Database 192.168.0.7/DB not responding. Using backup 192.168.0.8/DB"
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- "No response from statistics server. Statistics not sent"
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- Error（错误信息，举例如下：）
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- "Internal error. Cannot process request #12345 Error:...."
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- "Cannot perform login: credentials DB not responding"
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- Critical（致命错误，举例如下：）
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- "Critical panic received: .... Shutting down"
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- "Fatal error: ... App is shutting down to prevent data corruption or loss"
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可以看到每个函数里面都有对level的判断，所以如果我们在部署的时候设置了level=LevelWarning，那么Trace、Debug、Info这三个函数都不会有任何的输出，以此类推。
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## beego的配置设计
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配置信息的解析，beego实现了一个key=value的配置文件读取，类似ini配置文件的格式，就是一个文件解析的过程，然后把解析的数据保存到map中，最后在调用的时候通过几个string、int之类的函数调用返回相应的值，具体的实现请看下面：
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首先定义了一些ini配置文件的一些全局性常量 ：
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var (
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bComment = []byte{'#'}
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bEmpty = []byte{}
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bEqual = []byte{'='}
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bDQuote = []byte{'"'}
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)
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定义了配置文件的格式：
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// A Config represents the configuration.
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type Config struct {
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filename string
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comment map[int][]string // id: []{comment, key...}; id 1 is for main comment.
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data map[string]string // key: value
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offset map[string]int64 // key: offset; for editing.
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sync.RWMutex
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}
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定义了解析文件的函数，解析文件的过程是打开文件，然后一行一行的读取，解析注释、空行和key=value数据：
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// ParseFile creates a new Config and parses the file configuration from the
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// named file.
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func LoadConfig(name string) (*Config, error) {
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file, err := os.Open(name)
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if err != nil {
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return nil, err
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}
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cfg := &Config{
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file.Name(),
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make(map[int][]string),
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make(map[string]string),
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make(map[string]int64),
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sync.RWMutex{},
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}
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cfg.Lock()
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defer cfg.Unlock()
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defer file.Close()
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var comment bytes.Buffer
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buf := bufio.NewReader(file)
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for nComment, off := 0, int64(1); ; {
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line, _, err := buf.ReadLine()
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if err == io.EOF {
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break
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}
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if bytes.Equal(line, bEmpty) {
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continue
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}
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off += int64(len(line))
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if bytes.HasPrefix(line, bComment) {
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line = bytes.TrimLeft(line, "#")
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line = bytes.TrimLeftFunc(line, unicode.IsSpace)
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comment.Write(line)
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comment.WriteByte('\n')
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continue
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}
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if comment.Len() != 0 {
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cfg.comment[nComment] = []string{comment.String()}
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comment.Reset()
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nComment++
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}
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val := bytes.SplitN(line, bEqual, 2)
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if bytes.HasPrefix(val[1], bDQuote) {
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val[1] = bytes.Trim(val[1], `"`)
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}
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key := strings.TrimSpace(string(val[0]))
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cfg.comment[nComment-1] = append(cfg.comment[nComment-1], key)
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cfg.data[key] = strings.TrimSpace(string(val[1]))
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cfg.offset[key] = off
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}
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return cfg, nil
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}
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下面实现了一些读取配置文件的函数，返回的值确定为bool、int、float64或string：
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// Bool returns the boolean value for a given key.
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func (c *Config) Bool(key string) (bool, error) {
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return strconv.ParseBool(c.data[key])
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}
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// Int returns the integer value for a given key.
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func (c *Config) Int(key string) (int, error) {
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return strconv.Atoi(c.data[key])
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}
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// Float returns the float value for a given key.
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func (c *Config) Float(key string) (float64, error) {
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return strconv.ParseFloat(c.data[key], 64)
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}
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// String returns the string value for a given key.
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func (c *Config) String(key string) string {
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return c.data[key]
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}
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## 应用指南
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下面这个函数是我一个应用中的例子，用来获取远程url地址的json数据，实现如下：
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func GetJson() {
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resp, err := http.Get(beego.AppConfig.String("url"))
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if err != nil {
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beego.Critical("http get info error")
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return
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}
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defer resp.Body.Close()
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body, err := ioutil.ReadAll(resp.Body)
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err = json.Unmarshal(body, &AllInfo)
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if err != nil {
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beego.Critical("error:", err)
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}
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}
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函数中调用了框架的日志函数`beego.Critical`函数用来报错，调用了`beego.AppConfig.String("url")`用来获取配置文件中的信息，配置文件的信息如下(app.conf)：
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appname = hs
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url ="http://www.api.com/api.html"
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## links
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* [目录](<preface.md>)
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* 上一章: [controller设计](<13.3.md>)
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* 下一节: [实现博客的增删改](<13.5.md>)
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# 13.4 Logs and configurations
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## The importance of logs and configuration
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It has been introduced in the log in our program development plays a very important role, through the debug log we can record our information, had introduced a logging system seelog, depending on the different log level output of this program for program development and deployment is crucial. We can set the level in program development low point, when the level is set to deploy high, so we developed the debugging information can be masked.
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Configuration module for application deployment involves a number of different server configuration information is very useful, for example, some database configuration information, monitor port, listen address, etc. can all be configured via the configuration file, so that our application will have great flexibility, the configuration file can be configured to be deployed in different machines, you can connect different databases and the like.
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## Beego log design
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beego deployment log design ideas from seelog, depending on the level for logging, but beego relatively lightweight logging system design, the use of the system log.Logger interfaces, the default output to os.Stdout, users can implement this interface then through beego.SetLogger set custom output, detailed implementation is as follows:
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// Log levels to control the logging output.
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const (
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LevelTrace = iota
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LevelDebug
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LevelInfo
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LevelWarning
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LevelError
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LevelCritical
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)
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// logLevel controls the global log level used by the logger.
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var level = LevelTrace
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// LogLevel returns the global log level and can be used in
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// own implementations of the logger interface.
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func Level() int {
|
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return level
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}
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|
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// SetLogLevel sets the global log level used by the simple
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// logger.
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func SetLevel(l int) {
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level = l
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}
|
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|
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This section implements the above log log grading system, the default level is the Trace, users can set different grading SetLevel.
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// logger references the used application logger.
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var BeeLogger = log.New(os.Stdout, "", log.Ldate|log.Ltime)
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// SetLogger sets a new logger.
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func SetLogger(l *log.Logger) {
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BeeLogger = l
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}
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// Trace logs a message at trace level.
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func Trace(v ...interface{}) {
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if level <= LevelTrace {
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BeeLogger.Printf("[T] %v\n", v)
|
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}
|
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}
|
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|
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// Debug logs a message at debug level.
|
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func Debug(v ...interface{}) {
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if level <= LevelDebug {
|
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BeeLogger.Printf("[D] %v\n", v)
|
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}
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}
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|
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// Info logs a message at info level.
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func Info(v ...interface{}) {
|
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if level <= LevelInfo {
|
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BeeLogger.Printf("[I] %v\n", v)
|
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}
|
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}
|
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|
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// Warning logs a message at warning level.
|
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func Warn(v ...interface{}) {
|
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if level <= LevelWarning {
|
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BeeLogger.Printf("[W] %v\n", v)
|
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}
|
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}
|
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|
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// Error logs a message at error level.
|
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func Error(v ...interface{}) {
|
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if level <= LevelError {
|
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BeeLogger.Printf("[E] %v\n", v)
|
||||
}
|
||||
}
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|
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// Critical logs a message at critical level.
|
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func Critical(v ...interface{}) {
|
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if level <= LevelCritical {
|
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BeeLogger.Printf("[C] %v\n", v)
|
||||
}
|
||||
}
|
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|
||||
Above this piece of code initializes a BeeLogger default object, the default output to os.Stdout, users can achieve a logger beego.SetLogger to set the interface output. Which are to achieve the six functions:
|
||||
|
||||
- Trace( general record information, for example as follows:)
|
||||
- "Entered parse function validation block"
|
||||
- "Validation: entered second 'if'"
|
||||
- "Dictionary 'Dict' is empty. Using default value"
|
||||
- Debug( debug information, for example as follows:)
|
||||
- "Web page requested: http://somesite.com Params = '...'"
|
||||
- "Response generated. Response size: 10000. Sending."
|
||||
- "New file received. Type: PNG Size: 20000"
|
||||
- Info( print information, for example as follows:)
|
||||
- "Web server restarted"
|
||||
- "Hourly statistics: Requested pages: 12345 Errors: 123..."
|
||||
- "Service paused. Waiting for 'resume' call"
|
||||
- Warn( warning messages, for example as follows:)
|
||||
- "Cache corrupted for file = 'test.file'. Reading from back-end"
|
||||
- "Database 192.168.0.7/DB not responding. Using backup 192.168.0.8/DB"
|
||||
- "No response from statistics server. Statistics not sent"
|
||||
- Error( error messages, for example as follows:)
|
||||
- "Internal error. Cannot process request# 12345 Error:...."
|
||||
- "Cannot perform login: credentials DB not responding"
|
||||
- Critical( fatal error, for example as follows:)
|
||||
- "Critical panic received:.... Shutting down"
|
||||
- "Fatal error:... App is shutting down to prevent data corruption or loss"
|
||||
|
||||
Each function can be seen on the level of judgment which has, so if we set at deployment time level = LevelWarning, then Trace, Debug, Info will not have any of these three functions output, and so on.
|
||||
|
||||
## Beego configuration design
|
||||
|
||||
Configuration information parsing, beego implements a key = value configuration file read, similar ini configuration file format is a file parsing process, and then parse the data saved to the map, the last time the call through several string, int sort of function call returns the corresponding value, see the following specific implementation:
|
||||
|
||||
First define some ini configuration file some global constants:
|
||||
|
||||
var (
|
||||
bComment = []byte{'#'}
|
||||
bEmpty = []byte{}
|
||||
bEqual = []byte{'='}
|
||||
bDQuote = []byte{'"'}
|
||||
)
|
||||
|
||||
Defines the format of the configuration file:
|
||||
|
||||
// A Config represents the configuration.
|
||||
type Config struct {
|
||||
filename string
|
||||
comment map[int][]string // id: []{comment, key...}; id 1 is for main comment.
|
||||
data map[string]string // key: value
|
||||
offset map[string]int64 // key: offset; for editing.
|
||||
sync.RWMutex
|
||||
}
|
||||
|
||||
|
||||
Defines a function parses the file, parses the file of the process is to open the file, and then read line by line, parse comments, blank lines, and key = value data:
|
||||
|
||||
// ParseFile creates a new Config and parses the file configuration from the
|
||||
// named file.
|
||||
func LoadConfig(name string) (*Config, error) {
|
||||
file, err := os.Open(name)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
cfg := &Config{
|
||||
file.Name(),
|
||||
make(map[int][]string),
|
||||
make(map[string]string),
|
||||
make(map[string]int64),
|
||||
sync.RWMutex{},
|
||||
}
|
||||
cfg.Lock()
|
||||
defer cfg.Unlock()
|
||||
defer file.Close()
|
||||
|
||||
var comment bytes.Buffer
|
||||
buf := bufio.NewReader(file)
|
||||
|
||||
for nComment, off := 0, int64(1); ; {
|
||||
line, _, err := buf.ReadLine()
|
||||
if err == io.EOF {
|
||||
break
|
||||
}
|
||||
if bytes.Equal(line, bEmpty) {
|
||||
continue
|
||||
}
|
||||
|
||||
off += int64(len(line))
|
||||
|
||||
if bytes.HasPrefix(line, bComment) {
|
||||
line = bytes.TrimLeft(line, "#")
|
||||
line = bytes.TrimLeftFunc(line, unicode.IsSpace)
|
||||
comment.Write(line)
|
||||
comment.WriteByte('\n')
|
||||
continue
|
||||
}
|
||||
if comment.Len() != 0 {
|
||||
cfg.comment[nComment] = []string{comment.String()}
|
||||
comment.Reset()
|
||||
nComment++
|
||||
}
|
||||
|
||||
val := bytes.SplitN(line, bEqual, 2)
|
||||
if bytes.HasPrefix(val[1], bDQuote) {
|
||||
val[1] = bytes.Trim(val[1], `"`)
|
||||
}
|
||||
|
||||
key := strings.TrimSpace(string(val[0]))
|
||||
cfg.comment[nComment-1] = append(cfg.comment[nComment-1], key)
|
||||
cfg.data[key] = strings.TrimSpace(string(val[1]))
|
||||
cfg.offset[key] = off
|
||||
}
|
||||
return cfg, nil
|
||||
}
|
||||
|
||||
Below reads the configuration file to achieve a number of functions, the return value is determined as bool, int, float64 or string:
|
||||
|
||||
// Bool returns the boolean value for a given key.
|
||||
func (c *Config) Bool(key string) (bool, error) {
|
||||
return strconv.ParseBool(c.data[key])
|
||||
}
|
||||
|
||||
// Int returns the integer value for a given key.
|
||||
func (c *Config) Int(key string) (int, error) {
|
||||
return strconv.Atoi(c.data[key])
|
||||
}
|
||||
|
||||
// Float returns the float value for a given key.
|
||||
func (c *Config) Float(key string) (float64, error) {
|
||||
return strconv.ParseFloat(c.data[key], 64)
|
||||
}
|
||||
|
||||
// String returns the string value for a given key.
|
||||
func (c *Config) String(key string) string {
|
||||
return c.data[key]
|
||||
}
|
||||
|
||||
## Application guide
|
||||
|
||||
The following function is an example of the application, to access remote URL address Json data to achieve the following:
|
||||
|
||||
func GetJson() {
|
||||
resp, err := http.Get(beego.AppConfig.String("url"))
|
||||
if err != nil {
|
||||
beego.Critical("http get info error")
|
||||
return
|
||||
}
|
||||
defer resp.Body.Close()
|
||||
body, err := ioutil.ReadAll(resp.Body)
|
||||
err = json.Unmarshal(body, &AllInfo)
|
||||
if err != nil {
|
||||
beego.Critical("error:", err)
|
||||
}
|
||||
}
|
||||
|
||||
Function calls the framework of the log function `beego.Critical` function is used to being given, called `beego.AppConfig.String(" url ")` is used to obtain the configuration information in the file, configuration files are as follows(app.conf ):
|
||||
|
||||
appname = hs
|
||||
url ="http://www.api.com/api.html"
|
||||
|
||||
## Links
|
||||
|
||||
- [Directory](preface.md)
|
||||
- Previous section: [Design controllers](13.3.md)
|
||||
- Next section: [Add, delete and update blogs](13.5.md)
|
||||
|
||||
Reference in New Issue
Block a user