fayer1986 / ecql

Erlang Cassandra CQL Driver

Erlang Cassandra CQL Driver

Cassandra Native CQL Driver written in Erlang/OTP.

Features

• CQL BINARY PROTOCOL v3 Support
• Username, Password Authentication
• Query, Prepare and Execute

Limits

• TODO: Batch Query Support
• TODO: Event Register
• TODO: SSL Support

Usage

Schema

schema/test.schema.md

Connect

Connect to localhost:9042:

{ok, C} = ecql:connect().

Connect to nodes with username, password:

CassNodes = [{"127.0.0.1", 9042}, {"192.168.1.4", 9042}],
{ok, C} = ecql:connect([{nodes, CassNodes}, {username, "cassandra"}, {password, "cassandra"}]).

Query

{ok, KeySpace} = ecql:query(C, "use test").

{ok, {TableSpec, Columns, Rows}} = ecql:query(C, "select * from test.tab").

{ok, {TableSpec, Columns, Rows}} = ecql:query(C, "select * from test.tab where first_id = ? and second_id = ?", [{bigint, 1}, 'secid']).

Async Query

{ok, Ref} = ecql:async_query(C, "select * from test.tab"),
receive
	{async_cql_reply, Ref, {ok, Result} ->
		io:format("Result: ~p~n", [Result]);
	{async_cql_reply, Ref, Error} ->
        io:format("Result: ~p~n", [Result])
after
	1000 -> error(timeout)
end.

Prepare

{ok, Id} = ecql:prepare(C, "select * from test.tab where first_id = ? and second_id = ?").

Execute

{ok, {TableSpec, Columns, Rows}} = ecql:execute(C, Id, [{bigint, 1}, 'secid']).

Close

ok = ecql:close(C).

Connect Options

-type option() :: {nodes,    [{host(), inet:port_number()}]}
                | {username, iolist()}
                | {password, iolist()}
                | {keyspace, iolist()}
                | {tcp_opts, [gen_tcp:connect_option()]}
                | {ssl,      boolean()}
                | {ssl_opts, [ssl:ssl_option()]}
                | {timeout,  timeout()}
                | {logger,   atom() | {atom(), atom()}}.

Logger

%% log to stdout with info level
ecql:start_link([{logger, info}]).

%% log to otp standard error_logger with warning level
ecql:start_link([{logger, {otp, warning}}]).

%% log to lager with error level
ecql:start_link([{logger, {lager, error}}]).

Logger modules

Module	Description
stdout	io:format
otp	error_logger
lager	lager

Logger Levels

all
debug
info
warning
error
critical
none

License

The MIT License (MIT)

Author

Feng Lee [email protected]