key fatal error not printed with default info level

[kares]

running beats with TLS configured:

  beats {
    id => "beats-tls"
    port => 5044

    ssl => true
    ssl_key => "/cert-bundle/logstash.key"
    ssl_certificate => "/cert-bundle/logstash.crt"
  }
}

and give the key is not in the expected format LS will only log this much:

[2020-11-27T14:54:15,359][INFO ][logstash.inputs.beats    ][main] Beats inputs: Starting input listener {:address=>"0.0.0.0:5044"}
[2020-11-27T14:54:15,639][ERROR][logstash.agent           ] Failed to execute action {:id=>:main, :action_type=>LogStash::ConvergeResult::FailedAction, :message=>"Could not execute action: PipelineAction::Create<main>, action_result: false", :backtrace=>nil}
[2020-11-27T14:54:15,810][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>9600}
[2020-11-27T14:54:20,876][INFO ][logstash.runner          ] Logstash shut down.
[2020-11-27T14:54:20,915][ERROR][org.logstash.Logstash    ] java.lang.IllegalStateException: Logstash stopped processing because of an error: (SystemExit) exit

---

only with --log.level debug the key issue (java.lang.IllegalArgumentException: File does not contain valid private key) is visible:

[2020-11-27T14:55:34,059][DEBUG][logstash.javapipeline    ][main] Pipeline terminated by worker error {:pipeline_id=>"main", :exception=>java.lang.IllegalArgumentException: File does not contain valid private key: /home/kares/workspace/work/elastic/plugins/logstash-input-beats/cert-bundle/logstash.key, :backtrace=>["io.netty.handler.ssl.SslContextBuilder.keyManager(io/netty/handler/ssl/SslContextBuilder.java:350)", "io.netty.handler.ssl.SslContextBuilder.forServer(io/netty/handler/ssl/SslContextBuilder.java:107)", "org.logstash.netty.SslContextBuilder.buildContext(org/logstash/netty/SslContextBuilder.java:145)", "java.lang.reflect.Method.invoke(java/lang/reflect/Method.java:498)", ..., "home.kares.workspace.work.elastic.logstash_minus_7_dot_9_dot_1.logstash_minus_core.lib.logstash.java_pipeline.run(/home/kares/workspace/work/elastic/logstash-7.9.1/logstash-core/lib/logstash/java_pipeline.rb:183)", "home.kares.workspace.work.elastic.logstash_minus_7_dot_9_dot_1.logstash_minus_core.lib.logstash.java_pipeline.RUBY$method$run$0$__VARARGS__(home/kares/workspace/work/elastic/logstash_minus_7_dot_9_dot_1/logstash_minus_core/lib/logstash//home/kares/workspace/work/elastic/logstash-7.9.1/logstash-core/lib/logstash/java_pipeline.rb)", "home.kares.workspace.work.elastic.logstash_minus_7_dot_9_dot_1.logstash_minus_core.lib.logstash.java_pipeline.start(/home/kares/workspace/work/elastic/logstash-7.9.1/logstash-core/lib/logstash/java_pipeline.rb:134)", "org.jruby.RubyProc.call(org/jruby/RubyProc.java:318)", "java.lang.Thread.run(java/lang/Thread.java:748)"], "pipeline.sources"=>["/home/kares/workspace/work/elastic/plugins/logstash-input-beats/logstash-tls.conf"], :thread=>"#<Thread:0x57b11b18 run>"}
[2020-11-27T14:55:34,080][ERROR][logstash.agent           ] Failed to execute action {:id=>:main, :action_type=>LogStash::ConvergeResult::FailedAction, :message=>"Could not execute action: PipelineAction::Create<main>, action_result: false", :backtrace=>nil}