Hi Eric, as mentioned before - please try to include relevant context with your questions. For example- 1. What version of Timbre are you using? 2. What appender are you using? 3. Have you ruled out the usual things like an insufficient log level, namespace filtering, etc.? Assuming you’re using the println appender on the latest version of Timbre and have ruled out other config issues (for example, by confirming that other standard exceptions log fine with the same config) - I’d check: 1. Do str and println work normally against an example Manifold exception? 2. Does (timbre/default-output-error-fn {:?err <ex>}) work against an example Manifold exception? If not, what error is thrown? If it’s not a config issue, my first guess would be that there’s something in your Manifold exceptions that could be tripping up the default stacktrace rendering (`default-output-error-fn`).

Sorry I was about to submit an example project

I use this code to reproduce:

@(->> (stream/->source [1 2 3])
      (stream/map (fn [x] (println :x-before x) (throw (Exception. "Boom")) (inc x)))
      (stream/consume (fn [x] (println x))))

Version of timbre is latest 6.3.1

And I don't have any config for Timbre in the project so it seems like some lib might be impacting it, I'm adding them one by one to the barebone project to see which one

ok it's fulcro com.fulcrologic/fulcro {:git/url "https://github.com/fulcrologic/fulcro.git" :sha "11a75f8957ec8984559769eca76c2130595e7648"}

log/*config* with fulcro

{:min-level :debug,
 :ns-filter #{"*"},
 :middleware [],
 :timestamp-opts
 {:pattern :iso8601, :locale :jvm-default, :timezone :utc},
 :output-fn #function[taoensso.timbre/default-output-fn],
 :appenders
 {:println
  {:enabled? true,
   :fn
   #function[taoensso.timbre.appenders.core/println-appender/fn--26619]}},
 :_init-config
 {:loaded-from-source [:default],
  :compile-time-config {:min-level nil, :ns-pattern "*"}}}

log/**config** without fulcro

{:min-level :debug,
 :ns-filter #{"*"},
 :middleware [],
 :timestamp-opts
 {:pattern :iso8601, :locale :jvm-default, :timezone :utc},
 :output-fn #function[taoensso.timbre/default-output-fn],
 :appenders
 {:println
  {:enabled? true,
   :fn
   #function[taoensso.timbre.appenders.core/println-appender/fn--16458]}},
 :_init-config
 {:loaded-from-source [:default],
  :compile-time-config {:min-level nil, :ns-pattern "*"}}}

They look exactly the same to me

using clojure -Stree I narroed down to com.taoensso/sente 1.16.2 (it was a transitive dep of fulcro)

So I guess it is that sl4j-api lib

clojure -Stree
org.clojure/clojure 1.11.1
  . org.clojure/spec.alpha 0.3.218
  . org.clojure/core.specs.alpha 0.2.62
com.taoensso/timbre 6.3.1
  . com.taoensso/encore 3.68.0
    . org.clojure/tools.reader 1.3.6 :newer-version
    . com.taoensso/truss 1.11.0
  . io.aviso/pretty 1.4.4
com.taoensso/sente 1.16.2
  . org.clojure/core.async 1.3.610
    . org.clojure/tools.analyzer.jvm 1.1.0
      . org.clojure/tools.analyzer 1.0.0
      . org.clojure/core.memoize 1.0.236
        . org.clojure/core.cache 1.0.207
          . org.clojure/data.priority-map 1.0.0
      . org.ow2.asm/asm 5.2
      X org.clojure/tools.reader 1.3.2 :older-version
  X com.taoensso/encore 3.12.1 :older-version
  . org.java-websocket/Java-WebSocket 1.5.1
    . org.slf4j/slf4j-api 1.7.25
  X org.clojure/tools.reader 1.3.5 :superseded
  X com.taoensso/timbre 5.1.2 :use-top
manifold/manifold 0.4.1
  . org.clojure/tools.logging 1.2.4
  . org.clj-commons/dirigiste 1.0.3
  . riddley/riddley 0.2.0
  . potemkin/potemkin 0.4.6
    . clj-tuple/clj-tuple 0.2.2
    X riddley/riddley 0.1.12 :older-version

No timbre:

Dec 12, 2023 6:22:18 PM clojure.tools.logging$eval8532$fn__8535 invoke
SEVERE: error in stream handler
java.lang.Exception: Boom
	at manifold.experiment$eval12890$fn__12893.invoke(experiment.clj:16)
	at manifold.stream$map$fn__11469.invoke(stream.clj:624)
	at manifold.stream.Callback.put(stream.clj:457)
	at manifold.stream.graph$async_send.invokeStatic(graph.clj:85)
	at manifold.stream.graph$async_send.invoke(graph.clj:79)
	at manifold.stream.graph$sync_connect$f__9311__auto____10635.invoke(graph.clj:289)
	at clojure.lang.AFn.run(AFn.java:22)
	at io.aleph.dirigiste.Executor$3.run(Executor.java:320)
	at io.aleph.dirigiste.Executor$Worker$1.run(Executor.java:62)
	at manifold.executor$thread_factory$reify__8630$f__8636.invoke(executor.clj:70)
	at clojure.lang.AFn.run(AFn.java:22)
	at java.base/java.lang.Thread.run(Thread.java:829)

Dec 12, 2023 6:23:22 PM clojure.tools.logging$eval9352$fn__9355 invoke
SEVERE: error in stream handler
java.lang.Exception: Boom
	at manifold.experiment$eval12645$fn__12648.invoke(experiment.clj:16)
	at manifold.stream$map$fn__12300.invoke(stream.clj:624)
	at manifold.stream.Callback.put(stream.clj:457)
	at manifold.stream.graph$async_send.invokeStatic(graph.clj:85)
	at manifold.stream.graph$async_send.invoke(graph.clj:79)
	at manifold.stream.graph$async_connect$this__11451.invoke(graph.clj:220)
	at manifold.stream.graph$async_connect$this__11451.invoke(graph.clj:199)
	at clojure.core$trampoline.invokeStatic(core.clj:6345)
	at clojure.core$trampoline.invoke(core.clj:6334)
	at manifold.stream.graph$async_connect.invokeStatic(graph.clj:194)
	at manifold.stream.graph$async_connect.invoke(graph.clj:133)
	at manifold.stream.graph$connect.invokeStatic(graph.clj:345)
	at manifold.stream.graph$connect.invoke(graph.clj:317)
	at manifold.stream$connect.invokeStatic(stream.clj:333)
	at manifold.stream$connect.invoke(stream.clj:303)
	at manifold.stream$connect_via.invokeStatic(stream.clj:518)
	at manifold.stream$connect_via.invoke(stream.clj:503)
	at manifold.stream$map.invokeStatic(stream.clj:622)
	at manifold.stream$map.invoke(stream.clj:618)
	at manifold.experiment$eval12645.invokeStatic(experiment.clj:16)
	at manifold.experiment$eval12645.invoke(experiment.clj:1)
	at clojure.lang.Compiler.eval(Compiler.java:7194)
	at clojure.lang.Compiler.load(Compiler.java:7653)
	at user$eval9014.invokeStatic(NO_SOURCE_FILE:1)
	at user$eval9014.invoke(NO_SOURCE_FILE:1)
	at clojure.lang.Compiler.eval(Compiler.java:7194)
	at clojure.lang.Compiler.eval(Compiler.java:7149)
	at clojure.core$eval.invokeStatic(core.clj:3215)
	at clojure.core$eval.invoke(core.clj:3211)
	at nrepl.middleware.interruptible_eval$evaluate$fn__1265$fn__1266.invoke(interruptible_eval.clj:87)
	at clojure.lang.AFn.applyToHelper(AFn.java:152)
	at clojure.lang.AFn.applyTo(AFn.java:144)
	at clojure.core$apply.invokeStatic(core.clj:667)
	at clojure.core$with_bindings_STAR_.invokeStatic(core.clj:1990)
	at clojure.core$with_bindings_STAR_.doInvoke(core.clj:1990)
	at clojure.lang.RestFn.invoke(RestFn.java:425)
	at nrepl.middleware.interruptible_eval$evaluate$fn__1265.invoke(interruptible_eval.clj:87)
	at clojure.main$repl$read_eval_print__9206$fn__9209.invoke(main.clj:437)
	at clojure.main$repl$read_eval_print__9206.invoke(main.clj:437)
	at clojure.main$repl$fn__9215.invoke(main.clj:458)
	at clojure.main$repl.invokeStatic(main.clj:458)
	at clojure.main$repl.doInvoke(main.clj:368)
	at clojure.lang.RestFn.invoke(RestFn.java:1523)
	at nrepl.middleware.interruptible_eval$evaluate.invokeStatic(interruptible_eval.clj:84)
	at nrepl.middleware.interruptible_eval$evaluate.invoke(interruptible_eval.clj:56)
	at nrepl.middleware.interruptible_eval$interruptible_eval$fn__1298$fn__1302.invoke(interruptible_eval.clj:152)
	at clojure.lang.AFn.run(AFn.java:22)
	at nrepl.middleware.session$session_exec$main_loop__1368$fn__1372.invoke(session.clj:218)
	at nrepl.middleware.session$session_exec$main_loop__1368.invoke(session.clj:217)
	at clojure.lang.AFn.run(AFn.java:22)
	at java.base/java.lang.Thread.run(Thread.java:829)

Timbre+Sente

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See  for further details.
:x-before 1

Sente with excluded timbre same as above

Fixed by adding org.java-websocket/Java-WebSocket {:mvn/version "1.5.1" :exclusions [org.slf4j/slf4j-api] :comment "fix "} to my project

I’m sorry Eric, but I’m finding it a bit difficult to understand the context here. From your example project, it looks like you’ve got Timbre and Manifold in a project and you’re calling this block of code-

@(->> (stream/->source [1 2 3])
      (stream/map (fn [x] (println :x-before x) (throw (Exception. "Boom")) (inc x)))
      (stream/consume (fn [x] (println x))))

@UASETR481 thanks I'll try that to sum up what I've been doing: • I tried a barebone project with only manifold and made it throw an exception, which got logged • then I added Timbre, it was still logging an exception, better formatted (so Timbre worked out, without any changes at all to config) • then I added Sente, and nothing was logged anymore but there was a WARN about slf4j using NOP, Timbre still had everything default • so I added the JavaWebsocket lib that Sente is using and excluded slf4j-api which it introduced and it got me back to point 2

but I suppose that with your suggestion I potentially don't have to be extra careful about transitive deps introducing slf4j?

then I added Timbre, it was still logging an exception, better formatted (so Timbre worked out, without any changes at all to config)This part doesn’t sound right to me. Manifold https://github.com/clj-commons/manifold/blob/c3fc69066f3abba0b5ab0f4c2b1c4338bcc61d19/project.clj#L7 tools.logging for its logging, so it’s not obvious to me how just adding Timbre as a dependency would cause Manifold to log using Timbre. Timbre doesn’t integrate with tools.logging automatically, so if Timbre’s somehow getting involved - my guess would be that you’ve got some other (possibly transitive) dependency that’s somehow involving Timbre. Anyway, to summarise my current understanding: 1. You want Manifold to do its internal error logging using Timbre 2. It seems that some set of (possibly transitive) dependencies was somehow making that happen automatically 3. But the behaviour seems to be fragile and can be messed up by adding other (possibly transitive) dependencies If that’s accurate, then I’d recommend checking Manifold’s docs to understand how it decides what tool to use for logging. There might be some way to explicitly choose. And it might be that it (or tools.logging) is using some kind of heuristic to try auto select (possibly explaining point 3). You might have luck with explicitly calling https://github.com/taoensso/timbre/blob/2547283c025173144c1233753960da16b6bac42b/src/taoensso/timbre/tools/logging.clj#L36 I linked to before, that’ll cause tools.logging calls to go via Timbre. But I’d also check Manifold’s docs to see what it says about logging.

@UASETR481 so I think you might be right and Timbre is not involved at all. 1. that would be nice since I'm using Timbre in my main project, although my priority is to not lose logs 2 .Sente transitive dependencies were definitely triggering that:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See  for further details.

Right so Timbre wasn't really part of the equation, it's really just that Sente was pulling a transitive dependency that brought slf4j in so the bare clojure.logging of manifold stopped working because slf4j was using the NOP logger implementation

and use-timbre fixes that 👍 thanks @UASETR481

Happy to hear that helped, thanks for following up 👍 Cheers!