Created question in FIWARE Q/A platform on 28-04-2016 at 14:04
Please, ANSWER this question AT https://stackoverflow.com/questions/36914589/how-to-combine-multiple-orion-entities-to-one-ckan-dataset-using-cygnus

Question:
how to combine multiple orion entities to one ckan dataset using cygnus?

Description:
Right now I'm trying to create a dataset for my orion data with all the entitys info.
I set up all correctly and when some data changes orion send a notification to cygnus and then, cygnus will add the data to ckan.
As seen in this image.

The problem is that cygnus create a ckan resource for each entity.
What could I do to make cygnus put all data in only one resource?
Thanks.

EDIT 1:

I just found that I can simplify by making just one subscription in orion.

{
"entities": [

] ...

Then I noticed the grouping feature (http://fiware-cygnus.readthedocs.io/en/develop/installation_and_administration_guide/grouping_rules_conf/index.html) in cygnus but right now I'm lost because cygnus don't want to load my grouping config file. It shows this error:

time=2016-05-03T05:32:29.658CDT | lvl=INFO | trans= | srv= | subsrv= | function=<init> | comp=Cygnus | msg=com.telefonica.iot.cygnus.interceptors.GroupingRules[58] : No grouping rules have been read
Exception in thread "Thread-1" java.lang.NullPointerException
at java.io.File.<init>(File.java:277)
at com.telefonica.iot.cygnus.interceptors.GroupingInterceptor$ConfigurationReader.run(GroupingInterceptor.java:244)

In my agent config file I have:

cygnusagent.sources.http-source.interceptors.gi.gropuing_rules_conf_file = /usr/cygnus/conf/grouping_rules.conf

And in grouping_rules.conf:

{
"grouping_rules": [

]
}

Edit 2:

I have all the lines as documentation said:

cygnusagent.sources = http-source
cygnusagent.sinks = ckan-sink
cygnusagent.channels = ckan-channel

cygnusagent.sources.http-source.channels = ckan-channel
cygnusagent.sources.http-source.type = org.apache.flume.source.http.HTTPSource
cygnusagent.sources.http-source.port = 5050
cygnusagent.sources.http-source.handler = com.telefonica.iot.cygnus.handlers.OrionRestHandler
cygnusagent.sources.http-source.handler.notification_target = /notify
cygnusagent.sources.http-source.handler.default_service = test
cygnusagent.sources.http-source.handler.default_service_path = /myhouse
cygnusagent.sources.http-source.handler.events_ttl = 5
cygnusagent.sources.http-source.interceptors = ts gi
cygnusagent.sources.http-source.interceptors.ts.type = timestamp
cygnusagent.sources.http-source.interceptors.gi.type = com.telefonica.iot.cygnus.interceptors.GroupingInterceptor$Builder
cygnusagent.sources.http-source.interceptors.gi.gropuing_rules_conf_file = /usr/cygnus/conf/grouping_rules.conf
cygnusagent.channels.ckan-channel.type = memory
cygnusagent.channels.ckan-channel.capacity = 1000
cygnusagent.channels.ckan-channel.transactionCapacity = 100

1. ============================================
2. OrionCKANSink configuration
3. channel name from where to read notification events
   cygnusagent.sinks.ckan-sink.channel = ckan-channel

1. sink class, must not be changed
   cygnusagent.sinks.ckan-sink.type = com.telefonica.iot.cygnus.sinks.OrionCKANSink

1. true if the grouping feature is enabled for this sink, false otherwise
   cygnusagent.sinks.ckan-sink.enable_grouping = true

1. true if lower case is wanted to forced in all the element names, false otherwise
   cygnusagent.sinks.hdfs-sink.enable_lowercase = false

1. the CKAN API key to use
   cygnusagent.sinks.ckan-sink.api_key = 436fffc8-b397-478a-92fd-bbc5ffaf8269

1. the FQDN/IP address for the CKAN API endpoint
   cygnusagent.sinks.ckan-sink.ckan_host = ckan-demo.ckan.io

1. the port for the CKAN API endpoint
   cygnusagent.sinks.ckan-sink.ckan_port = 80

1. Orion URL used to compose the resource URL with the convenience operation URL to query it
   cygnusagent.sinks.ckan-sink.orion_url = http://localhost:1026

1. how the attributes are stored, either per row either per column (row, column)
   cygnusagent.sinks.ckan-sink.attr_persistence = column

1. enable SSL for secure Http transportation; 'true' or 'false'
   cygnusagent.sinks.ckan-sink.ssl = false

1. number of notifications to be included within a processing batch
   cygnusagent.sinks.ckan-sink.batch_size = 100

1. timeout for batch accumulation
   cygnusagent.sinks.ckan-sink.batch_timeout = 60

1. number of retries upon persistence error
   cygnusagent.sinks.ckan-sink.batch_ttl = 10

The file rights seems ok to me:

[root@VM013cen-Prod conf]# ls *.conf -l
-rwxrwxrwx 1 cygnus cygnus 2675 may 3 06:45 agent_test.conf
-rwxrwxrwx 1 cygnus cygnus 258 may 3 05:08 grouping_rules.conf
-rwxr-xr-x 1 cygnus cygnus 135 mar 1 02:50 krb5_login.conf

The test pases ok:

Results :

Tests run: 80, Failures: 0, Errors: 0, Skipped: 0

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1:05.862s
[INFO] Finished at: Tue May 03 06:53:44 CDT 2016
[INFO] Final Memory: 41M/105M
[INFO] ------------------------------------------------------------------------

The startup command i use: /usr/cygnus/bin/cygnus-flume-ng agent --conf /usr/cygnus/conf/ -f /usr/cygnus/conf/agent_test.conf -n cygnusagent -Dflume.root.logger=INFO,console