1. High Performance Python
Microservice
Communication
Joe Cabrera
@greedoshotlast

2. Joe Cabrera
● Software engineer at Handshake
● Python programmer since 2009
● Author on various open source Python projects
Hi, I’m

3. Things to consider
● Speed
● Reliability
● Security
● Learning curve
○ Easy to learn
○ Easy to debug
○ Easy to fix

4. Traditional REST
● Serialization and Deserialization are expensive
● Decently reliable (HTTP)
● Several Authentication schemes
● Predefined Status Codes
● Easy learning curve
○ Lots of resources on it
○ Great frameworks built around it
○ Human-readable

5. GRPC
● 6x Faster
● Same reliable as REST
● More secure
○ Several Authentication schemes
○ Difficult to decode without schema
● Harder learning curve
○ Not as much documentation
○ Still very early days so you may have to roll your own
○ Not in plaintext so harder to debug
● Supports Duplex Streaming

6. HTTP/2
● Fully binary protocol
● Multiplexed Streams
● Priorities and Dependencies
● Header Compression
● Reset stream
● Server Push

7. GRPC Syntax
syntax = "proto2";
package example;
message Person {
required string name = 1;
required int32 id = 2;
optional string email = 3;
}

8. Using GRPC
# GPRC
import person_pb2
person = person_pb2.Person()
person.id = 1234
person.name = "John Doe"
person.email = "jdoe@example.com"
print(person.SerializeToString())

9. GRPC over HTTP/1.1
# GPRC
import person_pb2
from django.http import HttpResponse
from jwt_utils import encode_auth_token, decode_auth_token
def send_response(request):
if 'HTTP_AUTHORIZATION' in request.META and
isinstance(decode_auth_token(request.META['HTTP_AUTHORIZATION']),
int):
person = person_pb2.Person()
person.id = 1234
person.name = "John Doe"
person.email = "jdoe@example.com"
response = HttpResponse(person.SerializeToString())
return response
return HttpResponse('Unauthorized', status=401)

10. GRPC over HTTP/2
# GPRC
import person_pb2
# Twisted
from twisted.web import server
from twisted.web.resource import Resource
from twisted.web.static import File
from twisted.internet import reactor
from twisted.internet import endpoints
class Person(Resource):
isLeaf = True
def render_GET(self, request):
person = person_pb2.Person()
person.id = 1234
person.name = "John Doe"
person.email = "jdoe@example.com"
return person.SerializeToString()
if __name__ == "__main__":
site = server.Site(Simple())
server = endpoints.serverFromString(
reactor,
"ssl:port=5000:privateKey=key.pem:certKey=cert.pem",
)
server.listen(site)
reactor.run()

11. GRPC over HTTP/2
#GRPC
import person_pb2
# Hyper
from hyper import HTTPConnection
conn = HTTPConnection(host='localhost', port=5000)
conn.request('GET', '/')
resp = conn.get_response()
person = person_pb2.Person()
data = person.ParseFromString(resp.read())
print "Person ID:", person.id
print "Name:", person.name
if person.HasField('email'):
print "E-mail address:", person.email

12. Authentication with JSON Web Tokens
# JWT
import jwt
SECRET_KEY = "webuildthiscity"
def encode_auth_token(user_id):
"""
Generates the Auth Token
"""
try:
payload = {
'exp': datetime.datetime.utcnow() + datetime.timedelta(days=0, seconds=5),
'iat': datetime.datetime.utcnow(),
'sub': user_id
}
return jwt.encode(
payload,
SECRET_KEY,
algorithm='HS256'
)
except Exception as e:
return e
request.setHeader('Authorization', encode_auth_token('my_user'))

13. Authentication with JSON Web Tokens
# JWT
import jwt
SECRET_KEY = "webuildthiscity"
def decode_auth_token(auth_token):
"""
Decodes the auth token
"""
try:
payload = jwt.decode(auth_token, SECRET_KEY)
return payload['sub']
except jwt.ExpiredSignatureError:
return 'Signature expired. Please log in again.'
except jwt.InvalidTokenError:
return 'Invalid token. Please log in again.'
resp = conn.get_response()
if decode_auth_token(response.headers['Authorization']):

14. Resources
● JSON Web Token - https://jwt.io/
● PyJWT - https://pyjwt.readthedocs.io/en/latest/
● GRPC - https://grpc.io/
● Twisted - https://twistedmatrix.com/trac/
● Hyper - http://hyper.readthedocs.io/en/latest/
● HTTP/2 Spec - https://tools.ietf.org/html/rfc7540
● HTTP/2 Explained - https://http2-explained.haxx.se/content/en/

15. Thank you!
Watch @greedoshotlast for these slides