Big-Data-HPC-Platform/plugins/couchbase

#ECL Embedded Couchbase plugin

This is the ECL plugin to access Couchbase](http://www.couchbase.com/), an open-source, distributed multi-model NoSQL document-oriented database software package that is optimized for interactive applications. Freehand N1QL queries can be embedded within your ECL query.

Client access is based on libcouchbase (c interface provided by couchbase install) and libcouchbase-cxx (from https://github.com/couchbaselabs/libcouchbase-cxx)

##Installation and Dependencies

[libcouchbase] is installed via standard package managers

(https://github.com/couchbaselabs/libcouchbase-cxx) is included as a git submodule in HPCC-Platform. It will be built and integrated automatically when you build the HPCC-Platform project with the couchbase plugin flag turned on.

The recommended method for obtaining libcouchbase is via On Ubuntu: sudo apt-get install libcouchbase-dev libcouchbase2-bin build-essential

##Plugin Configuration

The ECL Embedded couchbase plugin uses sensible default configuration values but these can be modified via configuration parameters.

The accepted configuration parameters are as follows:

            Name                  Default Value
            server                "localhost"
            port                  8091
            user                  ""
            password              ""
            bucket                "default"
            useSSL                false

            detailed_errcodes
            operation_timeout
            config_total_timeout
            http_poolsize

Configuration parameters are declared as part of the ENDEMBED couchbase funtion definition. For example:

 boolean  eventstatus(REAL m) := EMBED(couchbase : server(10.0.0.1), port(8091),  bucket('mybucket'), user('myname'), detailed_errcodes(1), operation_timeout(5.5), config_total_timeout(15))
     ...
 ENDEMBED;

##N1QL Query Examples

            //Creates a primary index on 'mybucket' bucket
            createprimeindex() := EMBED(couchbase : server(server), port(port), bucket('mybucket'))
                            create primary index on iot;
            ENDEMBED;

            //Simple select returning scalar string
            string scalarsimpleselect() := EMBED(couchbase : server(server), port(port), bucket('mybucket'))
                            SELECT timestamp from mybucket where timestamp = '2016-06-06 11:36:05.657314-04:00' limit 1;
            ENDEMBED;

            //Simple parameterized select returning scalar numeric
            unsigned parameterizedselectbool(boolean m) := EMBED(couchbase : server(server), port(port),  bucket('mybucket'))
                            SELECT count(sequence) from mybucket where isStaleData = $m; // boolean value 'm' passed in
            ENDEMBED;

            flatrec := RECORD
    string latitude,
                            real4 longitude,
                            boolean isStaleData,
                            INTEGER sequence;
            END;

            // simple select returning flat record(s)
            dataset(flatrec) flatdatasetpreparedselect(REAL m) := EMBED(couchbase : server(server), port(port),  bucket('mybucket'))
                            SELECT contextualData.gps.latitude,contextualData.gps.longitude, isStaleData, sequence from mybucket where contextualData.gps.latitude = $m;
            ENDEMBED;

            XYRecord := RECORD
                STRING x,
                STRING y;
            END;

            //Function accepts row type
            boolean selectrow(row(XYRecord) values) := EMBED(couchbase : server(server), port(port),  bucket('mybucket'))
                            SELECT eventStatus from mybucket where accelx = $x and accely = $y;
            ENDEMBED;

            FullRec := RECORD
                            real4 accelx;
                            real4 accely;
                            real4 accelz;
                            string4 eventId;
                            boolean eventStatus;
                            string guid;
                            boolean isStaleData;
                            integer sequence;
                            integer sourceoffset;
                            unsigned sourcepartition;
                            string sourcetopic;
                            string timestamp;
                            dataset(locationDatarec) locationData;
            END;

            //Full select
            dataset(FullRec) fullselect() := EMBED(couchbase : server(server), port(port),  bucket('mybucket'))
                            SELECT mybucket.* from mybucket;
            ENDEMBED;