Apache thrift-RPC service cross languages
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The document describes the Apache Thrift framework, which enables cross-language RPC services, supporting multiple programming languages such as C++, Java, and Python. It outlines the steps for defining data structures and service interfaces using IDL, generating language bindings, and writing server and client scripts for a machine learning prediction service. An example is provided, demonstrating the process of predicting outcomes using a pre-trained model in a server-client architecture.
![Apache Thrift:
RPC service cross languages
2012/11/04
Jimmy Lai
r97922028 [at] ntu.edu.tw](https://image.slidesharecdn.com/apachethrift-121104042208-phpapp01/85/Apache-thrift-RPC-service-cross-languages-1-320.jpg)
![Step 3. Write Service and Client
• Server
class ClassifierHandler(object):
def __init__(self):
self.model = pkl.load(open('svm_model.pkl', 'rb'))
print 'loading model...'
def predict(self, feature):
return self.model.predict(feature)[0]
Thrift http://thrift.apache.org/ 9](https://image.slidesharecdn.com/apachethrift-121104042208-phpapp01/85/Apache-thrift-RPC-service-cross-languages-9-320.jpg)
![Client (2/2)
digits = datasets.load_digits()
data = zip(digits.data, digits.target)
random.shuffle(data)
for i in range(10):
result = client.predict(data[i][0])
answer = data[i][1]
if result == answer:
print 'Correct!'
else:
print 'Wrong: answer is %d, predicted as %d' % (answer,
result)
# Close!
transport.close() Thrift http://thrift.apache.org/ 11](https://image.slidesharecdn.com/apachethrift-121104042208-phpapp01/85/Apache-thrift-RPC-service-cross-languages-11-320.jpg)
Apache thrift-RPC service cross languages
- 1. Apache Thrift: RPC service cross languages 2012/11/04 Jimmy Lai r97922028 [at] ntu.edu.tw
- 2. Thrift Network Stack Thrift http://thrift.apache.org/ 2
- 3. Languages Supported • C++ • Java • C# • OCaml • Cocoa • Perl • D • PHP • Delphi • Python • Erlang • Ruby • Haskell • Smalltalk Thrift http://thrift.apache.org/ 3
- 4. Interface Description Language (IDL) Data structure 'bool' | 'byte' | 'i16' | 'i32' | 'i64' | 'double' | 'string' | 'binary' | 'slist' map set list • http://thrift.apache.org/docs/idl/ Thrift http://thrift.apache.org/ 4
- 5. Usage 1. Define data structure and service interface using IDL(interface description language) 2. Generate language binding library: thrift -gen py my.thrift 3. Write Server and Client using the generated library. You may refer the template file in thrift/tutorial directory. Thrift http://thrift.apache.org/ 5
- 6. Example • Scenario: • We have a prepared machine learning model, and we'd like to load the model in advance as a server to provide prediction service. Thrift http://thrift.apache.org/ 6
- 7. Step 1. Define data structure and service: classifier.thrift typedef list<double> Feature service Classifier{ i64 predict(1: Feature feature); } Thrift http://thrift.apache.org/ 7
- 8. Step 2. Generate binding library • thrift --gen py classifier.thrift • Code binding library in gen-py dir Thrift http://thrift.apache.org/ 8
- 9. Step 3. Write Service and Client • Server class ClassifierHandler(object): def __init__(self): self.model = pkl.load(open('svm_model.pkl', 'rb')) print 'loading model...' def predict(self, feature): return self.model.predict(feature)[0] Thrift http://thrift.apache.org/ 9
- 10. Client (1/2) # Make socket transport = TSocket.TSocket('localhost', 9090) # Buffering is critical. Raw sockets are very slow transport = TTransport.TBufferedTransport(transport) # Wrap in a protocol protocol = TBinaryProtocol.TBinaryProtocol(transport) # Create a client to use the protocol encoder client = Classifier.Client(protocol) # Connect! transport.open() Thrift http://thrift.apache.org/ 10
- 11. Client (2/2) digits = datasets.load_digits() data = zip(digits.data, digits.target) random.shuffle(data) for i in range(10): result = client.predict(data[i][0]) answer = data[i][1] if result == answer: print 'Correct!' else: print 'Wrong: answer is %d, predicted as %d' % (answer, result) # Close! transport.close() Thrift http://thrift.apache.org/ 11
- 12. Live Demo • See thrift_demo directory in https://bitbucket.org/noahsark/slideshare/ noahsark@localhost:~/workspace/thrift/gen-py$ ./PythonServer.py loading model... Starting the server... noahsark@localhost:~/workspace/thrift/gen-py$ ./PythonClient.py Correct! Correct! Correct! Correct! Correct! Correct! Correct! Wrong: answer is 8, predicted as 1 Correct! Correct! Thrift http://thrift.apache.org/ 12