As discussed in the Ingest APIs section of this chapter, a pipeline is formed by a list of supported processors that are executed sequentially. If an exception occurs, the whole process is halted. Let's show an exception with an example. The processor in the pipeline is to remove the rating field from the indexing document. However, the rating field is optional and it may not be present. When an error occurs, you can check out the root clause in the error field. When the field rating is missing in the remove processor, it shows you that the reason is field [rating] not present as part of path [rating]:
If the error can be ignored, you can set the optional ingore_failure parameter to true to silently ignore the failure and continue the execution of the next processor. Another choice is to use the on_failure parameter to catch the exception...
