Web Development with Clojure 3rd - Shadow.cljs REPL receiving DEBUG logs (page 123)

mnardell · 21 February 2022 15:37

In chapter 5, page 123 the reader of the book is instructed to start the Shadow.cljs REPL with:
$ npx shadow-cljs cljs-repl app

… upon entering that command from a terminal session (in the guestbook directory). the REPL seems to start correctly, however it becomes effectively unusable due to the repeated DEBUG level log message:

[XNIO-1 I/O-4] DEBUG io.undertow.websockets.core.request - UT025003: Decoding WebSocket Frame with opCode 1

Other than that I believe, everything seems to be running correctly. For example I can get a JS Alert to appear on the targeted browser by typing into the REPL
(js/alert "Hello")
The repeated DEBUG message makes it inconvenient working with the REPL, and I certainly would benefit from understanding how to properly configure the logging that I am seeing. I is not at al clear to me where I would find the logging configuration in the current set-up I have (I have followed the steps described in the book up to this point)

Thanks for any advice!

mnardell · 22 February 2022 06:07

I managed to find some online discussions related to this topic, connect the dots, and I found out where the logging levels are set in a Luminous project. One will find logback.xml configurations for dev, test, prod in the env/*/resources directories. Simply adding this xml element:
<logger name="io.undertow.websockets" level="warn" />
silences the undertow DEBUG messages and makes the Shadow.cljs REPL operable. For an example of the logback.xml , have a look at:

github.com

luminus-framework/examples/blob/master/guestbook/env/dev/resources/logback.xml

<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" scanPeriod="10 seconds">
    <statusListener class="ch.qos.logback.core.status.NopStatusListener" />
    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <!-- encoders are assigned the type
             ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
        <encoder>
            <charset>UTF-8</charset>
            <pattern>%date{ISO8601} [%thread] %-5level %logger{36} - %msg %n</pattern>
        </encoder>
    </appender>
    <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>log/guestbook.log</file>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <fileNamePattern>log/guestbook.%d{yyyy-MM-dd}.%i.log</fileNamePattern>
            <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                <maxFileSize>100MB</maxFileSize>
            </timeBasedFileNamingAndTriggeringPolicy>
            <!-- keep 30 days of history -->
            <maxHistory>30</maxHistory>

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Of course this all seems obvious to me now, but I felt rather at loss when I made this post. I suppose that is the nature of learning.

Thanks!