"Malformed scrollId" exception

[p-run]

Originally reported in elastic/elasticsearch#9469, they told me to report the issue here, so here goes:

One elasticdump invocation yields the following:

% elasticdump --input=http://localhost:9200/ --output=\$ 
Wed, 28 Jan 2015 18:07:28 GMT | {"error":"ElasticsearchIllegalArgumentException[Malformed scrollId []]","status":400}
[
]

What is a scrollId and why is it malformed? Google is of no help in understanding this error message.

This exception seems like a low-level one. It should be caught by higher level code and converted to a more meaningful error message, like, say, "index was not specified".

Update: this issue seems to happen only when I am trying to dump an elasticsearch instance which has no data. It further looks like elasticdump is sending an empty scrollid to elasticsearch in this case.

[evantahler]

I was able to reproduce this: It only happens when you request a dump of the whole cluster (no index specified), and there is no data (which must be the case with no indexes created)

[evantahler]

We'll have some better error messaging here #69

> ./bin/elasticdump --input http://localhost:9200/ --output ~/Desktop/out.json --all
Tue, 17 Feb 2015 06:43:58 GMT | starting dump
Tue, 17 Feb 2015 06:43:58 GMT | Unable to obtain scrollId; This tends to indicate an error with your index(es)
Tue, 17 Feb 2015 06:43:58 GMT | got 0 objects from source elasticsearch (offset: 0)
Tue, 17 Feb 2015 06:43:58 GMT | dump ended with error (get phase) => Error: Unable to obtain scrollId; This tends to indicate an error with your index(es)

[p-run]

So how am I meant to figure out what "an error with my index(es)" actually is from that message?

[evantahler]

See above, this only happens when you have no indexes.