Metabase 0.57.3 slack notifications error

valek · November 26, 2025, 1:19pm

Hello, I run Metabase in our kubernetes cluster from image metabase/metabase:v0.57.3 I set up the Slack integration and added the app to a private channel. When I created an alert and clicked Send now the notification wasn’t sent to Slack. I’ve checked logs, and there are these events:

2025-11-26 13:09:28,725 WARN notification.send :: Error sending to channel channel/slack {mb-channel_type=:channel/slack, mb-handler_id=6, mb-notification_id=5, mb-payload_type=:notification/card}
clojure.lang.ExceptionInfo: Error registering fonts: Metabase will not be able to send Pulses. This is a known issue with certain JVMs. See https://github.com/metabase/metabase/issues/7986 and for more details.
        at metabase.channel.render.style$register_fonts_BANG_.invokeStatic(style.clj:120)
        at metabase.channel.render.style$register_fonts_BANG_.invoke(style.clj:109)
        at metabase.channel.render.style$fn__99127$fn__99128.invoke(style.clj:124)
        at clojure.lang.Delay.realize(Delay.java:44)
        at clojure.lang.Delay.deref(Delay.java:59)
        at clojure.core$deref.invokeStatic(core.clj:2337)
        at clojure.core$deref.invoke(core.clj:2323)
        at metabase.channel.render.style$fn__99127$fn__99130.invoke(style.clj:125)
        at metabase.channel.render.js.svg$render_svg.invokeStatic(svg.clj:174)
        at metabase.channel.render.js.svg$render_svg.invoke(svg.clj:172)
        at metabase.channel.render.js.svg$svg_string__GT_bytes.invokeStatic(svg.clj:189)
        at metabase.channel.render.js.svg$svg_string__GT_bytes.invoke(svg.clj:186)
        at metabase.channel.render.body$fn__103141$f__14660__auto____103142.invoke(body.clj:412)
        at clojure.lang.MultiFn.invoke(MultiFn.java:261)
        at metabase.channel.render.card$render_pulse_card_body.invokeStatic(card.clj:154)
        at metabase.channel.render.card$render_pulse_card_body.invoke(card.clj:140)
        at metabase.channel.render.card$render_pulse_card.invokeStatic(card.clj:192)
        at metabase.channel.render.card$render_pulse_card.invoke(card.clj:171)
        at metabase.channel.render.card$render_pulse_card.invokeStatic(card.clj:179)
        at metabase.channel.render.card$render_pulse_card.invoke(card.clj:171)
        at metabase.channel.impl.slack$part__GT_sections_BANG_.invokeStatic(slack.clj:100)
        at metabase.channel.impl.slack$part__GT_sections_BANG_.invoke(slack.clj:87)
        at metabase.channel.impl.slack$part__GT_sections_BANG_.invokeStatic(slack.clj:90)
        at metabase.channel.impl.slack$part__GT_sections_BANG_.invoke(slack.clj:87)
        at metabase.channel.impl.slack$fn__118855$f__14660__auto____118858.invoke(slack.clj:151)
        at clojure.lang.MultiFn.invoke(MultiFn.java:239)
        at metabase.notification.send$send_notification_sync_BANG_$fn__104184$fn__104185$fn__104186$fn__104187$fn__104192$fn__104199$fn__104200.invoke(send.clj:167)
        at metabase.util.log$with_exception_context_fn.invokeStatic(log.clj:303)
        at metabase.util.log$with_exception_context_fn.invoke(log.clj:295)
        at metabase.notification.send$send_notification_sync_BANG_$fn__104184$fn__104185$fn__104186$fn__104187$fn__104192$fn__104199.invoke(send.clj:163)
        at metabase.util.log$with_thread_context_fn.invokeStatic(log.clj:85)
        at metabase.util.log$with_thread_context_fn.invoke(log.clj:71)
        at metabase.notification.send$send_notification_sync_BANG_$fn__104184$fn__104185$fn__104186$fn__104187$fn__104192.invoke(send.clj:163)
        at metabase.task_history.models.task_history$do_with_task_history.invokeStatic(task_history.clj:157)
        at metabase.task_history.models.task_history$do_with_task_history.invoke(task_history.clj:145)
        at metabase.notification.send$send_notification_sync_BANG_$fn__104184$fn__104185$fn__104186$fn__104187.invoke(send.clj:153)
        at metabase.notification.send$send_notification_sync_BANG_$fn__104184$fn__104185$fn__104186.invoke(send.clj:148)
        at metabase.util$do_with_timer_ms.invokeStatic(util.cljc:1309)
        at metabase.util$do_with_timer_ms.invoke(util.cljc:1304)
        at metabase.notification.send$send_notification_sync_BANG_$fn__104184$fn__104185.invoke(send.clj:144)
        at metabase.util.log$with_exception_context_fn.invokeStatic(log.clj:303)
        at metabase.util.log$with_exception_context_fn.invoke(log.clj:295)
        at metabase.notification.send$send_notification_sync_BANG_$fn__104184.invoke(send.clj:142)
        at metabase.util.log$with_thread_context_fn.invokeStatic(log.clj:85)
        at metabase.util.log$with_thread_context_fn.invoke(log.clj:71)
        at metabase.notification.send$send_notification_sync_BANG_.invokeStatic(send.clj:142)
        at metabase.notification.send$send_notification_sync_BANG_.invoke(send.clj:139)
        at metabase.notification.send$create_notification_dispatcher$start_worker_BANG___104331$fn__104332$fn__104333$fn__104334$fn__104335.invoke(send.clj:373)
        at metabase.util.log$with_exception_context_fn.invokeStatic(log.clj:303)
        at metabase.util.log$with_exception_context_fn.invoke(log.clj:295)
        at metabase.notification.send$create_notification_dispatcher$start_worker_BANG___104331$fn__104332$fn__104333$fn__104334.invoke(send.clj:372)
        at metabase.util.log$with_thread_context_fn.invokeStatic(log.clj:85)
        at metabase.util.log$with_thread_context_fn.invoke(log.clj:71)
        at metabase.notification.send$create_notification_dispatcher$start_worker_BANG___104331$fn__104332$fn__104333.invoke(send.clj:372)
        at metabase.notification.send$create_notification_dispatcher$start_worker_BANG___104331$fn__104332.invoke(send.clj:370)
        at clojure.lang.AFn.call(AFn.java:18)
        at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.base/java.lang.Thread.run(Unknown Source)
Caused by: java.io.IOException: Problem reading font data.
        at java.desktop/java.awt.Font.createFont0(Unknown Source)
        at java.desktop/java.awt.Font.createFont(Unknown Source)
        at metabase.channel.render.style$register_font_BANG_.invokeStatic(style.clj:107)
        at metabase.channel.render.style$register_font_BANG_.invoke(style.clj:104)
        at metabase.channel.render.style$register_fonts_BANG_.invokeStatic(style.clj:111)
        ... 59 more
2025-11-26 13:09:28,725 INFO notification.send :: Done processing notification {mb-notification_id=5, mb-payload_type=:notification/card}

How can I fix this issue? Thanks in advance!

dwhitemv · November 26, 2025, 2:11pm

Is there a writable temp space in the container? Metabase needs somewhere to extract fonts.

Also post the diagnostic info from Admin → Tools so we can see what JVM is running in the container.

Background information about that exception can be found in the linked GitHub issue:

github.com/metabase/metabase

Pulse: slack messaging not working - NullpointerException

opened 10:03AM - 06 Jul 18 UTC

closed 02:13AM - 15 May 20 UTC

joerg-etherapists

Type:Bug Priority:P1 Reporting/Pulses Metabot/General

We cannot use pulses via slack. The slack integration seems to be fine (no error… while saving the API Token of slack). It was working in the past - unfortunately we don't know exactly when it was broken. We tested it in the pulse section with the button "Send to Slack now" and it tells "Sending failed". See the stracktrace below. - Browser: Chrome Version 67.0.3396.99 (64-Bit), Firefox 60.0.2 (64-Bit) - OS: Ubuntu 17.10 - Databases: MySQL 5.5.60 - Metabase version: 0.29.0 - Metabase hosting environment: (Linux/Ubuntu 17.10, Java: openjdk version "1.8.0_171" ) - Metabase internal database: MySQL 5.5.60 Stracktrace in the logfile service.log: ``` 2018-07-06 11:48:55,555 [qtp1682623231-508] ERRORmetabase.middleware - POST /api/pulse/test 500 (5 s) (41 DB calls). {:message nil, :type java.lang.NullPointerException, :stacktrace ["pulse.render$render_to_png.invokeStatic(render.clj:334)" "pulse.render$render_to_png.invoke(render.clj:317)" "pulse.render$fn__23557$render_html_to_png__23562$fn__23566.invoke(render.clj:352)" "pulse.render$fn__23557$render_html_to_png__23562.invoke(render.clj:344)" "pulse.render$render_pulse_card_to_png.invokeStatic(render.clj:836)" "pulse.render$render_pulse_card_to_png.invoke(render.clj:833)" "pulse$create_slack_attachment_data$iter__32336__32340$fn__32341$fn__32342$fn__32345.invoke(pulse.clj:70)" "pulse$create_and_upload_slack_attachments_BANG_$iter__32359__32363$fn__32364$fn__32365.invoke(pulse.clj:81)" "pulse$create_and_upload_slack_attachments_BANG_$iter__32359__32363$fn__32364.invoke(pulse.clj:80)" "pulse$create_and_upload_slack_attachments_BANG_.invokeStatic(pulse.clj:79)" "pulse$create_and_upload_slack_attachments_BANG_.invoke(pulse.clj:76)" "pulse$fn__32447.invokeStatic(pulse.clj:202)" "pulse$fn__32447.invoke(pulse.clj:200)" "pulse$send_notifications_BANG_.invokeStatic(pulse.clj:215)" "pulse$send_notifications_BANG_.invoke(pulse.clj:213)" "pulse$send_pulse_BANG_.invokeStatic(pulse.clj:241)" "pulse$send_pulse_BANG_.doInvoke(pulse.clj:232)" "api.pulse$fn__38933$fn__38936.invoke(pulse.clj:156)" "api.common.internal$do_with_caught_api_exceptions.invokeStatic(internal.clj:254)" "api.common.internal$do_with_caught_api_exceptions.invoke(internal.clj:249)" "api.pulse$fn__38933.invokeStatic(pulse.clj:148)" "api.pulse$fn__38933.invoke(pulse.clj:148)" "middleware$enforce_authentication$fn__38506.invoke(middleware.clj:118)" "api.routes$fn__49410.invokeStatic(routes.clj:82)" "api.routes$fn__49410.invoke(routes.clj:82)" "routes$fn__49469$fn__49470.doInvoke(routes.clj:108)" "routes$fn__49469.invokeStatic(routes.clj:103)" "routes$fn__49469.invoke(routes.clj:103)" "middleware$log_api_call$fn__38605$fn__38607.invoke(middleware.clj:349)" "middleware$log_api_call$fn__38605.invoke(middleware.clj:348)" "middleware$add_security_headers$fn__38555.invoke(middleware.clj:251)" "core$wrap_streamed_json_response$fn__54821.invoke(core.clj:67)" "middleware$bind_current_user$fn__38510.invoke(middleware.clj:139)" "middleware$maybe_set_site_url$fn__38559.invoke(middleware.clj:275)"]} ```

valek · November 26, 2025, 4:19pm

Thank you! The issue was with read-only file system. Now it’s working perfectly.