Problems running Cygnus with Postgresql

1
votes

So I have installed Cygnus and in the simple test configuration case which I took from here (https://github.com/telefonicaid/fiware-cygnus/blob/master/cygnus-ngsi/README.md) everything works fine.

But I need Postgresql as a backend for my application. For this I adjusted the agent_1.conf file with all postgresql parameters found from http://fiware-cygnus.readthedocs.io/en/latest/cygnus-ngsi/installation_and_administration_guide/ngsi_agent_conf/

cygnus-ngsi.sources = http-source
cygnus-ngsi.sinks = postgresql-sink
cygnus-ngsi.channels = postgresql-channel

cygnus-ngsi.sources.http-source.channels = hdfs-channel mysql-channel ckan-channel mongo-channel sth-channel kafka-channel dynamo-channel postgresql-channel
cygnus-ngsi.sources.http-source.type = org.apache.flume.source.http.HTTPSource
cygnus-ngsi.sources.http-source.port = 5050
cygnus-ngsi.sources.http-source.handler = com.telefonica.iot.cygnus.handlers.NGSIRestHandler
cygnus-ngsi.sources.http-source.handler.notification_target = /notify
cygnus-ngsi.sources.http-source.handler.default_service = default
cygnus-ngsi.sources.http-source.handler.default_service_path = /
cygnus-ngsi.sources.http-source.interceptors = ts gi
cygnus-ngsi.sources.http-source.interceptors.gi.type = com.telefonica.iot.cygnus.interceptors.NGSIGroupingInterceptor$Builder
cygnus-ngsi.sources.http-source.interceptors.gi.grouping_rules_conf_file = /usr/cygnus/conf/grouping_rules.conf

cygnus-ngsi.sinks.postgresql-sink.channel = postgresql-channel
cygnus-ngsi.sinks.postgresql-sink.type = com.telefonica.iot.cygnus.sinks.NGSIPostgreSQLSink
cygnus-ngsi.sinks.postgresql-sink.postgresql_host = 127.0.0.1
cygnus-ngsi.sinks.postgresql-sink.postgresql_port = 5432
cygnus-ngsi.sinks.postgresql-sink.postgresql_database = myUser
cygnus-ngsi.sinks.postgresql-sink.postgresql_username = mydb
cygnus-ngsi.sinks.postgresql-sink.postgresql_password = xxxx
cygnus-ngsi.sinks.postgresql-sink.attr_persistence = row
cygnus-ngsi.sinks.postgresql-sink.batch_size = 100
cygnus-ngsi.sinks.postgresql-sink.batch_timeout = 30
cygnus-ngsi.sinks.postgresql-sink.batch_ttl = 10

# postgresql-channel configuration
cygnus-ngsi.channels.postgresql-channel.type = memory
cygnus-ngsi.channels.postgresql-channel.capacity = 1000
cygnus-ngsi.channels.postgresql-channel.transactionCapacity = 100

I didn'r really find any information about other files I am supposed to change and aren't really sure if all parameters are correct. I also tried the sample configuration from here http://fiware-cygnus.readthedocs.io/en/latest/cygnus-ngsi/flume_extensions_catalogue/ngsi_postgresql_sink/index.html

Cygnus seems to start correctly but all if I try to send a notification I get connection refused

1
postgresqlfiwarefiware-cygnus
cygnus-ngsi.sources.http-source.channels = postgresql-channel should be enough if you are only using postgresql channel. "connection refused" means that cygnus didn't start at all. So, nothing is listening on port 5050 (or you might have your iptables configured to reject connections). Please, send the logs of cygnus as it starts – jicarretero
Could you provide more info about the error, perhaps error logs? Note that if you use PostgreSQL, you must create database tables before Cygnus starts to store data in it. Otherwise, it will return some error. – Emiliano Viotti
Sorry to ask such a question, but following the "installation" you refer to in your question... Is it possible that you have "cygnusagent" in /usr/cygnus/conf/cygnus_instance_1.conf and cygnus-ngsi in your agent_1.conf? – jicarretero
I get a response from cygnus now (there was a type in cygnus_instance). So I wanted to check now the writing to postgresql and set for it the batch size to 1 so every entry should get written immediately but nothing seems to happen. In the log it also doesn't specify the reason for failure I would suspect that the table is wrong... Here is the log: pastebin.com/TBPZT7h5 – telopk
Is there also somewhere a minimal example of a working configuration with postgresql on which one could build? – telopk

1 Answers

0
votes

Befor doing anything, please, create the database, the user and the password in Postgresql.

The cygnus configuration is like this one. The /etc/cygnus/conf/cygnus_instance_1.conf file:

CYGNUS_USER=cygnus
CONFIG_FOLDER=/usr/cygnus/conf
CONFIG_FILE=/usr/cygnus/conf/agent_1.conf
AGENT_NAME=cygnus-ngsi
LOGFILE_NAME=cygnus.log
ADMIN_PORT=8081
POLLING_INTERVAL=30

So, the other file /usr/cygnus/conf/agent_1.conf is like this one (please change PostgreSQL parameters):

cygnus-ngsi.sources = http-source
cygnus-ngsi.sinks = postgresql-sink
cygnus-ngsi.channels = postgresql-channel

cygnus-ngsi.sources.http-source.channels = postgresql-channel
cygnus-ngsi.sources.http-source.type = org.apache.flume.source.http.HTTPSource
cygnus-ngsi.sources.http-source.port = 5050
cygnus-ngsi.sources.http-source.handler = com.telefonica.iot.cygnus.handlers.NGSIRestHandler
cygnus-ngsi.sources.http-source.handler.notification_target = /notify
cygnus-ngsi.sources.http-source.handler.default_service = default
cygnus-ngsi.sources.http-source.handler.default_service_path = /
cygnus-ngsi.sources.http-source.handler.events_ttl = 10
cygnus-ngsi.sources.http-source.interceptors = ts gi
cygnus-ngsi.sources.http-source.interceptors.ts.type = timestamp
cygnus-ngsi.sources.http-source.interceptors.gi.type = com.telefonica.iot.cygnus.interceptors.NGSIGroupingInterceptor$Builder
#cygnus-ngsi.sources.http-source.interceptors.gi.grouping_rules_conf_file = /usr/cygnus/conf/grouping_rules.conf

# =============================================
# postgresql-channel configuration
# channel type (must not be changed)
cygnus-ngsi.channels.postgresql-channel.type = memory
# capacity of the channel
cygnus-ngsi.channels.postgresql-channel.capacity = 1000
# amount of bytes that can be sent per transaction
cygnus-ngsi.channels.postgresql-channel.transactionCapacity = 100

# ============================================
# NGSIPostgreSQLSink configuration
# channel name from where to read notification events
cygnus-ngsi.sinks.postgresql-sink.channel = postgresql-channel
# sink class, must not be changed
cygnus-ngsi.sinks.postgresql-sink.type = com.telefonica.iot.cygnus.sinks.NGSIPostgreSQLSink
# true applies the new encoding, false applies the old encoding.
# cygnus-ngsi.sinks.postgresql-sink.enable_encoding = false
# true if the grouping feature is enabled for this sink, false otherwise
cygnus-ngsi.sinks.postgresql-sink.enable_grouping = false
# true if name mappings are enabled for this sink, false otherwise
cygnus-ngsi.sinks.postgresql-sink.enable_name_mappings = false
# true if lower case is wanted to forced in all the element names, false otherwise
# cygnus-ngsi.sinks.postgresql-sink.enable_lowercase = false
# the FQDN/IP address where the PostgreSQL server runs
cygnus-ngsi.sinks.postgresql-sink.postgresql_host = 127.0.0.1
# the port where the PostgreSQL server listens for incomming connections
cygnus-ngsi.sinks.postgresql-sink.postgresql_port = 5432
# the name of the postgresql database
cygnus-ngsi.sinks.postgresql-sink.postgresql_database = cygnusdb
# a valid user in the PostgreSQL server
cygnus-ngsi.sinks.postgresql-sink.postgresql_username = cygnus
# password for the user above
cygnus-ngsi.sinks.postgresql-sink.postgresql_password = cygnusdb
# how the attributes are stored, either per row either per column (row, column)
cygnus-ngsi.sinks.postgresql-sink.attr_persistence = row
# select the data_model: dm-by-service-path or dm-by-entity
cygnus-ngsi.sinks.postgresql-sink.data_model = dm-by-entity
# number of notifications to be included within a processing batch
cygnus-ngsi.sinks.postgresql-sink.batch_size = 1
# timeout for batch accumulation
cygnus-ngsi.sinks.postgresql-sink.batch_timeout = 30
# number of retries upon persistence error
cygnus-ngsi.sinks.postgresql-sink.batch_ttl = 0
# true enables cache, false disables cache
cygnus-ngsi.sinks.postgresql-sink.backend.enable_cache = true