Erlang RPC Demo Code

This project was created for an Erlang DC 2011 talk presented by Rusty Klophaus (http://erlangdc.com/speakers/rusty_klophaus).

It contains sample code demonstrating cross-language RPC where Erlang is the server. In other words, it demonstrates how to call into an Erlang service with an Erlang or Ruby client.

• Expose an Erlang service over REST (via Webmachine and Spooky), BERT-RPC, and Protocol Buffers.
• Connect an Erlang client to the Erlang service over REST, BERT-RPC, or Protocol Buffers.
• Connect a Ruby client to the Erlang service over REST, BERT-RPC, or Protocol Buffers.

The service generates a list of numbers. For example:

sequence(5) -> {ok, ["1", "2", "3", "4", "5"]}.

The service is exposed on the following endpoints:

• REST via Webmachine (http://localhost:8001/sequence/5)
• REST via Spooky (http://localhost:8002/sequence/5)
• Ernie (port 9999, {call, ernie_sequence, sequence, [5]})
• Protocol Buffers (port 8003)

This project also contains a benchmarking harness for Basho Bench that exercises the Erlang service via the four provided endpoints.

Files

Misc.

• src/sequence.erl - Contains the "service" logic. Simply generates a list of numbers.
• lib/rpc_demo.rb - Ruby clients.
• src/rpc_demo.erl - Helper functions and Erlang clients.

REST Interface

• src/spooky_sequence.erl - Callback module for REST interface. (Spooky)
• src/webmachine_sequence.erl - Callback module for REST interface. (Webmachine)

BERT-RPC Interface

• src/ernie_sequence.erl - Callback module for BERT-RPC interface (Ernie server).

Protocol Buffers

• src/protobuff_server_listener.erl - Waits for incoming PB connections
• src/protobuff_server_sup.erl - Supervise PB connections.
• src/protobuff_server.erl - Serve a PB connection.
• src/rpc_demo.proto - Protocol Buffers definition file.
• src/gen_nb_server.erl - Non-blocking server. Used by protobuff_server_listener.

Benchmarking

• src/rpc_demo_basho_bench_driver.erl - Driver for Basho Bench performance test.
• priv/rpc_demo.config - Basho Bench config file.

Benchmarking

Test 1 - Encoding and Decoding

Objective: Demonstrate which encoding scheme (JSON, BERT, or PB) is the fastest.

Test 2 - Single Hop, Small Payload

Objective: Demonstrate which interface is the fastest with a small payload (sequence(5), 44 bytes) over a single hop. (Ping times <1 ms.)

Test 3 - Single Hop, Large Payload

Objective: Demonstrate which interface is the fastest with a large payload (sequence(20000), 190kb) over a single hop. (Ping times <1 ms.)

Test 4 - Multiple Hops, Small Payload

Objective: Demonstrate which interface is the fastest with a small payload (sequence(5), 44 bytes) over multiple hops. (Ping times ~50 ms.)

Test 5 - Multiple Hops, Large Payload

Objective: Demonstrate which interface is the fastest with a large payload (sequence(20000), 190kb) over multiple hops. (Ping times ~50 ms.)