Log missing file exception when failing to read metadata snapshot

[ginolzh]

There is a logging statement that is able to catch two exception types (FileNotFoundException or NoSuchFileException) but cannot distinguish which type of exception occurred just base on the log message. Maybe adding a stack trace could help.

[elasticmachine]

Pinging @elastic/es-distributed

[dnhatn]

LGTM.

@elasticmachine test this please.

[jasontedor]

Yet these two exceptions represent the same failure: a file that is not found?

[ginolzh]

Maybe there're some slight differences between these two exceptions, according to the java documentation it describes FileNotFoundException as:
"This exception will be thrown by the FileInputStream, FileOutputStream, and RandomAccessFile constructors when a file with the specified pathname does not exist. It will also be thrown by these constructors if the file does exist but for some reason is inaccessible, for example when an attempt is made to open a read-only file for writing."

And for NoSuchFileException it is: "Checked exception thrown when an attempt is made to access a file that does not exist."

[bleskes]

@jasontedor anything you want done here?

[ywelsch]

LGTM. While logging the exception, we also get info about the file that's missing. Given that this should very rarely happen, I think it's ok having the stack trace.

[ywelsch]

@elasticmachine test this please