[英]wai-logger FileLogSpec as Scotty Middleware reporting openFile: resource busy (file is locked)
I am using Scotty for a backend application in Haskell and I am interested in logging all requests to a file.我正在将 Scotty 用于 Haskell 中的后端应用程序,并且我有兴趣将所有请求记录到文件中。 The existing wai-middleware requestlogger is not enough as I would like the properties of FileLogSpec , since I like have multiple but short logfiles, which FileLogSpec permits.
现有的 wai-middleware requestlogger是不够的,因为我想要FileLogSpec的属性,因为我喜欢 FileLogSpec 允许的多个但很短的日志文件。
I am also open to alternative solutions on the logging issue, but I am not interested in switching from Scotty.我也对日志记录问题的替代解决方案持开放态度,但我对从 Scotty 切换不感兴趣。
My problem is, that after the first request I get this error:我的问题是,在第一次请求后我收到此错误:
openFile: resource busy (file is locked)
openFile: resource busy (file is locked)
and the application stops logging entirely.并且应用程序完全停止记录。
My current implementation making wai-logger into a middleware is:我目前将 wai-logger 变成中间件的实现是:
-- type Middleware = Application -> Application
-- Type Application = Request -> (Response -> IO ResponseReceived) -> IO ResponseReceived
mw :: Wai.Middleware
mw (app::Wai.Application) (req::Request) (fRes::(Response -> IO ResponseReceived)) =
app req myResponseFunction
where
myResponseFunction :: Response -> IO ResponseReceived
myResponseFunction response = do
logger' <- logger
logger' req (Wai.responseStatus response) Nothing
fRes response
logger :: IO Logger.ApacheLogger
logger = createLoggerActions >>= return . Logger.apacheLogger
createLoggerActions :: IO Logger.ApacheLoggerActions
createLoggerActions = let
-- 5 MB in bytes = 5242880
mb5InBytes = 5242880
-- From fast-logger default
defaultBufSize = 4096 in
Logger.initLogger
Logger.FromFallback
(Logger.LogFile Logger.FileLogSpec {Logger.log_file = "reqLogger", Logger.log_file_size = mb5InBytes, Logger.log_backup_number = 5} defaultBufSize)
( return $ B.pack "%d/%b/%Y:%T %z")
I have tried using bracket to clean up the logger as follows:我尝试使用括号来清理记录器,如下所示:
mw :: Wai.Middleware
mw (app::Wai.Application) (req::Request) (fRes::(Response -> IO ResponseReceived)) =
let loggerActions = createLoggerActions in
bracket_ setup (teardown loggerActions) $
app req (myResponseFunction loggerActions)
where
myResponseFunction :: IO Logger.ApacheLoggerActions -> Response -> IO ResponseReceived
myResponseFunction loggerActions response = do
logger' <- logger loggerActions
logger' req (Wai.responseStatus response) Nothing
fRes response
logger :: IO Logger.ApacheLoggerActions -> IO Logger.ApacheLogger
logger loggerActions = loggerActions >>= return . Logger.apacheLogger
createLoggerActions :: IO Logger.ApacheLoggerActions
createLoggerActions = let
-- 5 MB in bytes = 5242880
mb5InBytes = 5242880
-- From fast-logger default
defaultBufSize = 4096 in
Logger.initLogger
Logger.FromFallback
(Logger.LogFile Logger.FileLogSpec {Logger.log_file = "reqLogger", Logger.log_file_size = mb5InBytes, Logger.log_backup_number = 5} defaultBufSize)
( return $ B.pack "%d/%b/%Y:%T %z")
setup :: IO ()
setup = return ()
teardown :: IO (Logger.ApacheLoggerActions) -> IO ()
teardown loggerActions = loggerActions >>= Logger.logRemover
And here is how I use it:这是我使用它的方式:
someFunc :: IO ()
someFunc = do
appConfig <- loadAppConfig
workingDir <- Dir.getCurrentDirectory
putStrLn $ "Working directory: " <> workingDir
case appConfig of
Nothing -> putStrLn "Failed to load appconfig.json"
Just appConfig' ->
let checkSizeRequirement' = checkSizeRequirement (sizeLimitGB appConfig') in
scotty 3000 $ do
--middleware logStdoutDev
middleware $ mw
middleware $ staticPolicy (addBase "./ElmFeFMI/")
post "/api/fmichecker" ...
Unfortunately, this led to the same result.不幸的是,这导致了同样的结果。
I have created an issue on wai logger as well: https://github.com/kazu-yamamoto/logger/issues/183我也在 wai 记录器上创建了一个问题: https://github.com/kazu-yamamoto/logger/issues/183
The full source is available here: https://github.com/into-cps-association/utilities_backend完整的源代码在这里: https://github.com/into-cps-association/utilities_backend
sicklorkin from irc freenode #haskell responded with the rather obvious solution -来自 irc freenode #haskell 的icklorkin 给出了一个相当明显的解决方案——
Make sure you havn't accidentally opened the logger twice
确保您没有意外打开记录器两次
and asked me to try passing in the logger.并让我尝试传入记录器。
So the new and working solution is:因此,新的有效解决方案是:
someFunc :: IO ()
someFunc = do
appConfig <- loadAppConfig
workingDir <- Dir.getCurrentDirectory
putStrLn $ "Working directory: " <> workingDir
fileLogger <- createLogger
case appConfig of
Nothing -> putStrLn "Failed to load appconfig.json"
Just appConfig' ->
let checkSizeRequirement' = checkSizeRequirement (sizeLimitGB appConfig') in
scotty 3000 $ do
--middleware logStdoutDev
middleware $ (mw fileLogger)
And further down the mw has been split from createLogger:再往下,mw 已从 createLogger 中分离出来:
mw :: Logger.ApacheLogger -> Wai.Middleware
mw logger (app::Wai.Application) (req::Request) (fRes::(Response -> IO ResponseReceived)) =
app req myResponseFunction
where
myResponseFunction :: Response -> IO ResponseReceived
myResponseFunction response = do
logger req (Wai.responseStatus response) Nothing
fRes response
createLogger :: IO Logger.ApacheLogger
createLogger = createLoggerActions >>= return . Logger.apacheLogger
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