88 lines
2.6 KiB
Racket
88 lines
2.6 KiB
Racket
#lang scribble/manual
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@(require scribble/eval "utils.rkt" (for-label racket unstable/logging))
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@(define the-eval (make-base-eval))
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@(the-eval '(require unstable/logging))
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@title{Logging}
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@defmodule[unstable/logging]
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This module provides tools for logging.
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@unstable[@author+email["Vincent St-Amour" "stamourv@racket-lang.org"]]
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@defproc[(with-logging-to-port
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[port output-port?] [proc (-> any)]
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[#:level level (or/c 'fatal 'error 'warning 'info 'debug) 'debug])
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any]{
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Runs @racket[proc], outputting any logging of level @racket[level] or higher to
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@racket[port]. Returns whatever @racket[proc] returns.
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@defexamples[
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#:eval the-eval
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(let ([my-log (open-output-string)])
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(with-logging-to-port my-log
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(lambda ()
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(log-warning "Warning World!")
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(+ 2 2))
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#:level 'warning)
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(get-output-string my-log))]}
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@defproc[(with-intercepted-logging
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[interceptor (-> (vector/c
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(or/c 'fatal 'error 'warning 'info 'debug)
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string?
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any/c)
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any)]
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[proc (-> any)]
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[#:level level (or/c 'fatal 'error 'warning 'info 'debug) 'debug])
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any]{
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Runs @racket[proc], calling @racket[interceptor] on any log message of level
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@racket[level] or higher. @racket[interceptor] receives the entire log vectors
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(see @secref["receiving-logged-events" #:doc '(lib "scribblings/reference/reference.scrbl")])
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as arguments. Returns whatever @racket[proc] returns.
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@defexamples[
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#:eval the-eval
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(let ([warning-counter 0])
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(with-intercepted-logging
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(lambda (l)
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(when (eq? (vector-ref l 0) ; actual level
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'warning)
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(set! warning-counter (add1 warning-counter))))
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(lambda ()
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(log-warning "Warning!")
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(log-warning "Warning again!")
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(+ 2 2))
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#:level 'warning)
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warning-counter)]}
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A lower-level interface to logging is also available.
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@deftogether[[
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@defproc[(start-recording
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[#:level level (or/c 'fatal 'error 'warning 'info 'debug) 'debug])
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listener?]
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@defproc[(stop-recording [listener listener?])
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(listof (vector/c (or/c 'fatal 'error 'warning 'info 'debug)
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string?
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any/c))]]]{
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@racket[start-recording] starts recording log messages of the desired level or
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higher. Messages will be recorded until stopped by passing the returned
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listener object to @racket[stop-recording]. @racket[stop-recording] will then
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return a list of the log messages that have been reported.
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@defexamples[
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#:eval the-eval
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(define l (start-recording #:level 'warning))
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(log-warning "1")
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(log-warning "2")
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(stop-recording l)
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]}
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