Flume shell error messages are not useful

From feedback:

Command failed" is not helpful at all. Tailing master log, I see something slightly more useful in some cases, in other cases less useful. "Sometimes ""due to null"":

[flume localhost:35873] exec config todd-desktop tail('/var/log/messages') console
Failed to run command 'exec config todd-desktop tail('/var/log/messages') console' due to null
10/06/24 23:11:00 ERROR util.FlumeShell: Failed to run command 'exec config todd-desktop tail('/var/log/messages') console'

Sometimes just failed:

[flume localhost:35873] exec config todd-desktop ""tail('/var/log/messages')"" console
[id: 4] Execing command : config
Command failed

Tailing the log, it's sometimes useful, but other times I get stuff like:

10/06/24 23:10:17 ERROR master.CommandManager: Error executing command: config [todd-desktop, console]
java.lang.IllegalArgumentException
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:75)
at com.cloudera.flume.master.ConfigCommand$1.exec(ConfigCommand.java:83)

which is not useful - use the multiarg form of Preconditions checks so you get a message out the top"