December 2021 - slf4j-dev - mailman3.qos.ch

[JIRA] Updates for SLF4J-371: Support the lambda expression in the Logger
by QOS.CH (JIRA) 27 Dec '21

27 Dec '21

SLF4J / SLF4J-371 [Resolved] Support the lambda expression in the Logger ============================== Here's what changed in this issue in the last few minutes. There is 1 comment. View or comment on issue using this link https://jira.qos.ch/browse/SLF4J-371 ============================== 1 comment ------------------------------ Eric Kolotyluk on 27/Dec/21 4:05 PM Ahhh, now I see it... >From [https://www.slf4j.org/manual.html#fluent] I did not see the last example {code:java} // using fluent API, add one argument with a Supplier and then log message with one more argument. // Assume the method t16() returns 16. logger.atDebug().addArgument(() -> t16()).log(msg, "Temperature set to {}. Old temperature was {}.", oldT); {code} It is very subtle and could be 'marketed' better as lambda support. Wrapping my head around an unfamiliar API was very distracting when my mission was to just use lambdas. I tested this in my code, and yes, it does work. However, I will stay with {code:java} import kr.pe.kwonnam.slf4jlambda.LambdaLogger; import kr.pe.kwonnam.slf4jlambda.LambdaLoggerFactory; . . . static final LambdaLogger logger = LambdaLoggerFactory.getLogger(LagTests.class); {code} As it does exactly what I want, and it keeps my code from looking too ugly with Fluent calling conventions. {code:java} Callable task = () -> {System.out.println("task evaluated"); return "called";}; logger1.debug("Lazy logging {}", task); logger2.atDebug().addArgument(task).log("Lazy logging {}"); {code} I really do not understand the objections to adding to slf4j what slf4jlambda does so well. It seems to me people are trying to advocate for Fluent rather than just a support a simple facade for logging that supports lambdas in a very natural way. Forcing people to use Fluent just to get lambdas is very manipulative. ============================== This message was sent by Atlassian Jira (v8.8.0#808000-sha1:e2c7e59)

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[JIRA] Updates for SLF4J-371: Support the lambda expression in the Logger
by QOS.CH (JIRA) 26 Dec '21

26 Dec '21

SLF4J / SLF4J-371 [Resolved] Support the lambda expression in the Logger ============================== Here's what changed in this issue in the last few minutes. There is 1 comment. View or comment on issue using this link https://jira.qos.ch/browse/SLF4J-371 ============================== 1 comment ------------------------------ Alexander Kiselyov on 26/Dec/21 10:57 PM [~ekolotyluk], I might be missing your point, but I guess any of these 2 samples does what you intended to: {code:java} Supplier<String> task = () -> { System.out.println("task evaluated"); return "called"; }; logger.atDebug().addArgument(task).log("Lazy logging {}");{code} {code:java} logger.atDebug().addArgument(() -> { System.out.println("task evaluated"); return "called"; }).log("Lazy logging {}"); {code} This has an extra call compared to your desired sample (in general N calls will be required, where N is a number of parameters, since there's no varargs version of [addArgument|https://www.slf4j.org/api/org/slf4j/spi/LoggingEventBuilder.htm…] or {{addKeyValue}}, which may actually be useful to have). The version you published ({{log("Lazy logging {}", task.call())}}) simply can't work in any other way: {{task.call()}} is not a [method reference expression|https://docs.oracle.com/javase/specs/jls/se11/html/jls-15.html#j…] ("refer to the invocation of a method without actually performing the invocation"), but just a regular method invocation, so will obviously be executed by JVM in order to evaluate all the {{log()}} method arguments prior to its actual invocation (again, according to Java Language Specification). ============================== This message was sent by Atlassian Jira (v8.8.0#808000-sha1:e2c7e59)

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[JIRA] Updates for SLF4J-371: Support the lambda expression in the Logger
by QOS.CH (JIRA) 26 Dec '21

26 Dec '21

SLF4J / SLF4J-371 [Resolved] Support the lambda expression in the Logger ============================== Here's what changed in this issue in the last few minutes. There is 1 comment. View or comment on issue using this link https://jira.qos.ch/browse/SLF4J-371 ============================== 1 comment ------------------------------ Eric Kolotyluk on 26/Dec/21 4:56 AM Yup, slf4j-lambda works exactly as I want, and testing proves it behaves as I want, and even works with Fluent... ============================== This message was sent by Atlassian Jira (v8.8.0#808000-sha1:e2c7e59)

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[JIRA] Updates for SLF4J-371: Support the lambda expression in the Logger
by QOS.CH (JIRA) 26 Dec '21

26 Dec '21

SLF4J / SLF4J-371 [Resolved] Support the lambda expression in the Logger ============================== Here's what changed in this issue in the last few minutes. There is 1 comment. View or comment on issue using this link https://jira.qos.ch/browse/SLF4J-371 ============================== 1 comment ------------------------------ Eric Kolotyluk on 26/Dec/21 2:46 AM I don't want all of log4j's interface, just lambdas, please. For me, Fluent is unnecessary and complex, whereas lambdas offer more utility. I have also found Fluent to be unreliable, and the error cases are difficult to reproduce, otherwise, I would report them. Of course, there may be some technical reason, I am unaware of, that SLF4J cannot support lambdas. ============================== This message was sent by Atlassian Jira (v8.8.0#808000-sha1:e2c7e59)

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[JIRA] Updates for SLF4J-371: Support the lambda expression in the Logger
by QOS.CH (JIRA) 25 Dec '21

25 Dec '21

SLF4J / SLF4J-371 [Resolved] Support the lambda expression in the Logger ============================== Here's what changed in this issue in the last few minutes. There is 1 comment. View or comment on issue using this link https://jira.qos.ch/browse/SLF4J-371 ============================== 1 comment ------------------------------ Ceki Gülcü on 25/Dec/21 11:39 PM I am sorry if you don't like the fluent API in SLF4J. Good APIs are not so easy to articulate. Anyway, in my opinion, {{org.apache.logging.log4j.Logger}} interface is quite crowded and as such an unlikely source of emulation. ============================== This message was sent by Atlassian Jira (v8.8.0#808000-sha1:e2c7e59)

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[JIRA] Updates for SLF4J-371: Support the lambda expression in the Logger
by QOS.CH (JIRA) 25 Dec '21

25 Dec '21

SLF4J / SLF4J-371 [Resolved] Support the lambda expression in the Logger ============================== Here's what changed in this issue in the last few minutes. There is 1 comment. View or comment on issue using this link https://jira.qos.ch/browse/SLF4J-371 ============================== 1 comment ------------------------------ Eric Kolotyluk on 25/Dec/21 4:24 PM I am asking for Lambdas because Fluent does not do what I want, and I don't believe Fluent can do what I want. Are you saying it is impossible to add log4j2 style Lambdas to slf4j? ============================== This message was sent by Atlassian Jira (v8.8.0#808000-sha1:e2c7e59)

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[JIRA] Updates for SLF4J-371: Support the lambda expression in the Logger
by QOS.CH (JIRA) 25 Dec '21

25 Dec '21

SLF4J / SLF4J-371 [Resolved] Support the lambda expression in the Logger ============================== Here's what changed in this issue in the last few minutes. There is 1 comment. View or comment on issue using this link https://jira.qos.ch/browse/SLF4J-371 ============================== 1 comment ------------------------------ Ceki Gülcü on 25/Dec/21 12:23 PM [~ekolotyluk] The expression {{logger.atDebug().log("Lazy logging {}", task.call());}} will invoke task's {{call}} method independently of the API. It is not clear what you are asking for or you are asking for the impossible. ============================== This message was sent by Atlassian Jira (v8.8.0#808000-sha1:e2c7e59)

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[JIRA] Updates for SLF4J-530: Lambdas should not be evaluated
by QOS.CH (JIRA) 25 Dec '21

25 Dec '21

SLF4J / SLF4J-530 [Open] Lambdas should not be evaluated ============================== Here's what changed in this issue in the last few minutes. This issue has been created View or comment on issue using this link https://jira.qos.ch/browse/SLF4J-530 ============================== Issue created ------------------------------ Ceki Gülcü created this issue on 25/Dec/21 12:04 PM Summary: Lambdas should not be evaluated Issue Type: Sub-task Assignee: Ceki Gülcü Created: 25/Dec/21 12:04 PM Priority: Major Reporter: Ceki Gülcü ============================== This message was sent by Atlassian Jira (v8.8.0#808000-sha1:e2c7e59)

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[JIRA] Updates for SLF4J-371: Support the lambda expression in the Logger
by QOS.CH (JIRA) 24 Dec '21

24 Dec '21

SLF4J / SLF4J-371 [Resolved] Support the lambda expression in the Logger ============================== Here's what changed in this issue in the last few minutes. There is 1 comment. View or comment on issue using this link https://jira.qos.ch/browse/SLF4J-371 ============================== 1 comment ------------------------------ Eric Kolotyluk on 24/Dec/21 10:08 PM Please support log4j2 style lambda expressions... While playing with fluent in 2.0.0-alpha5 {code:java} Callable task = () -> {System.out.println("task evaluated"); return "called";}; logger.atDebug().log("Lazy logging {}", task.call()); {code} At log level "debug" it prints {code:java} task evaluated 15:39:38.061 [main] DEBUG net.kolotyluk.net.LagTests - Lazy logging called {code} but at log level "info" it still prints {code:java} task evaluated {code} Also, IMHO, fluent log statements are ugly. Using lambdas, {code:java} logger.debug(() -> { ... }){code} would give me 90% of what I want, whereas {code:java} logger.debug("format {} ... {}", () -> {...}, () -> {...}) {code} is just gravy. ============================== This message was sent by Atlassian Jira (v8.8.0#808000-sha1:e2c7e59)

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[qos-ch/slf4j] 59100d: add atLevel method to SubstituteLogger
by Ceki Gülcü 24 Dec '21

24 Dec '21

Branch: refs/heads/master Home: https://github.com/qos-ch/slf4j Commit: 59100d75e1e24af49e464928856fafb2bed0fccd https://github.com/qos-ch/slf4j/commit/59100d75e1e24af49e464928856fafb2bed0… Author: Ceki Gulcu <ceki(a)qos.ch> Date: 2021-12-24 (Fri, 24 Dec 2021) Changed paths: M slf4j-api/src/main/java/org/slf4j/helpers/SubstituteLogger.java Log Message: ----------- add atLevel method to SubstituteLogger Signed-off-by: Ceki Gulcu <ceki(a)qos.ch>

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