Why does my file consumer not pick up the file, and how do I let the file consumer use the Camel error handler?
There could be several reasons why the File consumer is
not picking up files. For example it may not run at all, or it cannot
acquire a read lock on the file.
Check the logs for any exceptions or other
informative messages. You can
turn on DEBUG logging at
org.apache.camel.component.file to see more detail.
How to use Camel’s routing error handlers with the file consumer
Well, this is really a "chicken or the egg" question. The Camel error handler (e.g., in the routes) only applies when a message is being routed by the routing engine. Before this happens, a consumer must successfully receive a message, create a Camel Exchange, populate the Exchange with message details (e.g., body and headers), and then pass the Exchange to the routing engine. Only at this point can the routing error handler deal with exceptions occurring. Before this point, any error handling is really component-specific.
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Bridge with error handler From Camel 2.10 onwards the file and ftp consumers can now bridge to the
Camel routing engine’s error handler. See more details at the
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If the component consumer extends the
DefaultConsumer
from Camel, then it offers an
org.apache.camel.spi.ExceptionHandler
hook for end users to plug-in a custom strategy. The default
implementation from Camel is
LoggingExceptionHandler
that will log the exception at ERROR/WARN level, and then ignore the
exception.
See the File page in the bottom for an example how to
use a custom ExceptionHandler that sends a new message to the Camel
routing engine, which then allows the routing engine to trigger its own
error handling to deal with the exception.