cqlc Example Application

This is an example application to demonstrate how cqlc can be used in a Go application. It is very basic and is not is any way an exhaustive showcase of the runtime API. It is just designed to show you how to use the cqlc tool with a real app.

cqlc is a source code generation tool that reads a schema from a given keyspace in Cassandra and produces strongly typed binding code for use in a Go application.

This example consists of:

• An example CQL schema for Cassandra;
• A Makefile that applies this schema to a local Cassandra instance and invokes cqlc to generate Go source code bindings for this schema;
• A simple main method that shows how to read/write to/from Cassandra using the generated bindings;

Pre-requisites

• Go (only 1.2 has been tested, but other versions may work as well);
• Apache Cassandra (2.0.3 has been tested, but other versions will probably work too);
• cqlc needs to be available on your $PATH;
• (Optionally) cqlsh needs to be on your $PATH (if you use the supplied Makefile)

Getting cqlc

To install cqlc:

$ go get github.com/relops/cqlc

After installing this, make sure that the bin directory of your $GOPATH is in in your $PATH, so that the cqlc executable is available in your shell.

Generating the binding code

Running

$ make schema

Will apply the schema from the schema.cql to a local instance of Cassandra. By default, the Makefile assumes that the Cassandra instance it should connect to is running on 127.0.0.1. The default keyspace is called twitter_example - this will be created if it not exist.

Generating the binding code

By default, the generated code is written to src/twitter/generated_schema.go by running the default target from the Makefile:

$ make default
  cqlc -i 127.0.0.1 -k twitter_example -p twitter -o src/twitter/generated_schema.go
  Reading schema from keyspace: twitter_example

Running main.go

Once you have generated the binding code, make sure that it is on your local $GOPATH. For example, in the current directory, run:

$ export GOPATH=$GOPATH:`pwd`

such that pwd/src/generated is on the $GOPATH.

Now you should be able to run:

$ go run main.go 
2014/01/16 18:06:29 Got tweets: [{Id:1 Name:tweeter}]