英文:
Go logging with multiple backend
问题
我正在使用go-logging,并尝试构建一个具有可变数量的Backends
(即stderr + file + syslog + ...)的日志记录器。因此,我的程序会读取一个配置文件,并根据定义创建日志记录器。
由于SetBackend是一个可变参数函数,我以为可以使用切片作为参数,但我错了。
以下是我的代码示例:
func configureLogger(debug, file bool) {
var backendList = []logging.Backend{}
var format = logging.MustStringFormatter(
`%{color}%{time:15:04:05.000} [%{level:.4s}] %{shortfunc}%{color:reset}: %{message}`,
)
if debug {
consoleBackend := logging.NewLogBackend(os.Stderr, "", 0)
consoleBackendFormatter := logging.NewBackendFormatter(consoleBackend, format)
consoleBackendLeveled := logging.AddModuleLevel(consoleBackendFormatter)
consoleBackendLeveled.SetLevel(logging.DEBUG, "")
backendList = append(backendList, consoleBackendLeveled)
}
if file {
f, err := os.OpenFile("file.log", os.O_APPEND|os.O_CREATE|os.O_RDWR, 0644)
filebackend := logging.NewLogBackend(f, "", 0)
filebackendFormatter := logging.NewBackendFormatter(filebackend, format)
filebackendLeveled := logging.AddModuleLevel(filebackendFormatter)
filebackendLeveled.SetLevel(logging.DEBUG, "")
backendList = append(backendList, filebackendLeveled)
}
logging.SetBackend(backendList)
}
这会导致以下错误:
cannot use backendList (type []logging.Backend) as type logging.Backend in argument to logging.SetBackend:
[]logging.Backend does not implement logging.Backend (missing Log method)
我漏掉了什么?
英文:
I'm using go-logging and I'm trying to build a logger with a variable number of Backends
(i.e. stderr + file + syslog + ...). So my program reads a configuration file, and create the logger according to what's defined.
As SetBackend is a variadic function, I thought I could use a slice as argument, but I was wrong.
Here is an example of my code:
func configureLogger(debug, file bool) {
var backendList = []logging.Backend{}
var format = logging.MustStringFormatter(
`%{color}%{time:15:04:05.000} [%{level:.4s}] %{shortfunc}%{color:reset}: %{message}`,
)
if debug {
consoleBackend := logging.NewLogBackend(os.Stderr, "", 0)
consoleBackendFormatter := logging.NewBackendFormatter(consoleBackend, format)
consoleBackendLeveled := logging.AddModuleLevel(consoleBackendFormatter)
consoleBackendLeveled.SetLevel(logging.DEBUG, "")
backendList = append(backendList, consoleBackendLeveled)
}
if file {
f, err := os.OpenFile("file.log", os.O_APPEND|os.O_CREATE|os.O_RDWR, 0644)
filebackend := logging.NewLogBackend(f, "", 0)
filebackendFormatter := logging.NewBackendFormatter(filebackend, format)
filebackendLeveled := logging.AddModuleLevel(filebackendFormatter)
filebackendLeveled.SetLevel(logging.DEBUG, "")
backendList = append(backendList, filebackendLeveled)
}
logging.SetBackend(backendList)
}
This end up with the following error:
cannot use backendList (type []logging.Backend) as type logging.Backend in argument to logging.SetBackend:
[]logging.Backend does not implement logging.Backend (missing Log method)
What am I missing?
答案1
得分: 2
我发现了一个好的语法。当将切片传递给可变参数函数时,你需要在切片名称后面添加...
,如规范中所示:https://golang.org/ref/spec#Passing_arguments_to_..._parameters
正确的语法是:
logging.SetBackend(backendList...)
英文:
I was missing the good syntax. When passing a slice to a variadic function, you need to add ...
after your slice name, as shown in the specs: https://golang.org/ref/spec#Passing_arguments_to_..._parameters
The right syntax is:
logging.SetBackend(backendList...)
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