What is the grok pattern for this jenkins log? - regex

Question

Can you please help me with the grok pattern for this jenkins sample data or log. The log is only a single line.
hudson.slaves.CommandLauncher launch\nSEVERE: Unable to launch the agent for dot-dewsttlas403-ci\njava.io.IOException: Failed to create a temporary file in /opt_shared/iit_slave/jenkins_slave/workspace\n\tat hudson.util.AtomicFileWriter.<init>(AtomicFileWriter.java:144)\n\tat hudson.util.AtomicFileWriter.<init>(AtomicFileWriter.java:109)\n\tat hudson.util.AtomicFileWriter.<init>(AtomicFileWriter.java:84)\n\tat hudson.util.AtomicFileWriter.<init>(AtomicFileWriter.java:74)\n\tat hudson.util.TextFile.write(TextFile.java:116)\n\tat jenkins.branch.WorkspaceLocatorImpl$WriteAtomic.invoke(WorkspaceLocatorImpl.java:264)\n\tat jenkins.branch.WorkspaceLocatorImpl$WriteAtomic.invoke(WorkspaceLocatorImpl.java:256)\n\tat hudson.FilePath$FileCallableWrapper.call(FilePath.java:3042)\n\tat hudson.remoting.UserRequest.perform(UserRequest.java:212)\n\tat hudson.remoting.UserRequest.perform(UserRequest.java:54)\n\tat hudson.remoting.Request$2.run(Request.java:369)\n\tat hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)\n\tat java.util.concurrent.FutureTask.run(FutureTask.java:266)\n\tat java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)\n\tat java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)\n\tat java.lang.Thread.run(Thread.java:745)\n\tSuppressed: hudson.remoting.Channel$CallSiteStackTrace: Remote call to dot-dewsttlas403-ci\n\t\tat hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1743)\n\t\tat hudson.remoting.UserRequest$ExceptionResponse.retrieve(UserRequest.java:357)\n\t\tat hudson.remoting.Channel.call(Channel.java:957)\n\t\tat hudson.FilePath.act(FilePath.java:1069)\n\t\tat hudson.FilePath.act(FilePath.java:1058)\n\t\tat jenkins.branch.WorkspaceLocatorImpl.save(WorkspaceLocatorImpl.java:254)\n\t\tat jenkins.branch.WorkspaceLocatorImpl.access$500(WorkspaceLocatorImpl.java:80)\n\t\tat jenkins.branch.WorkspaceLocatorImpl$Collector.onOnline(WorkspaceLocatorImpl.java:561)\n\t\tat hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:697)\n\t\tat hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:432)\n\t\tat hudson.slaves.CommandLauncher.launch(CommandLauncher.java:154)\n\t\tat hudson.slaves.SlaveComputer$1.call(SlaveComputer.java:294)\n\t\tat jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)\n\t\tat jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:71)\n\t\tat java.util.concurrent.FutureTask.run(Unknown Source)\n\t\tat java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)\n\t\tat java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)\n\t\tat java.lang.Thread.run(Unknown Source)\nCaused by: java.io.IOException: No space left on device\n\tat java.io.UnixFileSystem.createFileExclusively(Native Method)\n\tat java.io.File.createTempFile(File.java:2024)\n\tat hudson.util.AtomicFileWriter.<init>(AtomicFileWriter.java:142)\n\t... 15 more\n
I am only interested to extract the following from the above logs.
agent status, agent name
Expected Result:
agent status: Unable
agent name: dot-dewsttlas403-ci

Answer 1

SEVERE: %{DATA:agent_status} to launch the agent for %{DATA:agent_name}\\n
This should give you the result you are interested in, but it would only work if the structure of the message is the same.
Configuration used:
input {stdin{}}
filter{
grok {
match =>{
"message" => "SEVERE: %{DATA:agent_status} to launch the agent for %{DATA:agent_name}\\n"
}
}
}
output {stdout{codec => json}}
Result:
{
"host": "MY_COMPUTER",
"agent_status": "Unable",
"message": "hudson.slaves.CommandLauncher launch\\nSEVERE: Unable to launch the agent for dot-dewsttlas403-ci\\njava.io.IOException: Failed to create a temporary file in /opt_shared/iit_slave/jenkins_slave/workspace\\n\\tat \r",
"agent_name": "dot-dewsttlas403-ci",
"#timestamp": "2020-01-29T16:54:27.256Z",
"#version": "1"
}
Also to help you next time you're working with logstash-grok:
An online tester for patterns:
http://grokconstructor.appspot.com/do/match
The basic grok patterns: https://github.com/logstash-plugins/logstash-patterns-core/blob/master/patterns/grok-patterns