The author explains why they switched from primarily using Python to primarily using Go for serious projects. Some key reasons include that Go has better performance, code quality, testing, and concurrency features compared to Python. While Python is still good for hobby projects, Go enforces error handling, has built-in profiling tools, and makes deployment easier due to compiling to a single binary.

1. Why I switch from
python to Go?
weng.wei@zalora.com

2. About Myself
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Coding python since 2006
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Speaker @ PyCon China 2013
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Architect @ zalora.com
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https://github.com/Wuvist
!
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Switching to Go last year

3. “Switching”
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Before:
•
•
•
Love Python
python for all projects
After:
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Still love python
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python for hobby projects
•
go for serious projects

4. “Serious Projects”
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Performance is critical
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Code Quality is important
!
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OK, mostly web projects

5. Performance

6. •
http://www.techempower.com/benchmarks/

7. Do you use pypy?

8. “benchmark could be very misleading”

9. Stress test on real Go API

10. Requests/sec:
Transfer/sec:
18071.20
1.19GB

11. •
Just anything
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Can python?
•
Can nginx?

12. Why Go is so fast?
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Async
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Compiled
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Multi-cores

13. Python
tornado
tornado
tornado
nginx (4 workers)
tornado

14. nginx <-> tornado
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Inter-process communication is slow
•
•
memory copy
•
•
network latency
parsing
Process overhead

15. Python
memcached
tornado
tornado
tornado
nginx (4 workers)
tornado

16. Go
Go binary with GroupCache
https://github.com/golang/groupcache

17. Performance
•
Care abut performance? You must consider go
•
http://blog.cloudflare.com/go-at-cloudflare

18. Code Quality

19. Error
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Python: scripting language
•
•
deal with run-time errors
Go: compiled language
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deal with compile-time errors

20. Exception Handling
https://twitter.com/yinwang0/status/417899535344472065

21. Python
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All exception checked?
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Which one will crash the process?
!
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Dunno?
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Service running in “unknown state” is the worse
thing could happen on production server!

22. Exception in Go
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error
•
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Must check
panic
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Crash

23. Hacky
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Go doesn’t enforce error checking
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Go enforce all variable usage

25. ➜ ~GOPATH git:(feature/rpccache) ✗ go run h.go
# command-line-arguments
./h.go:8: err declared and not used

27. Test
•
Python
•
•
Are you actually using pyunit?
Go
•
go test

28. https://github.com/Wuvist/gophpserialize

29. https://github.com/Wuvist/gophpserialize/blob/master/
gophpserialize_test.go

30. ➜ gophpserialize git:(master) go test -v
=== RUN TestUnmarshal
--- PASS: TestUnmarshal (0.00 seconds)
=== RUN TestPhpToJson
--- PASS: TestPhpToJson (0.00 seconds)
=== RUN TestPhpToJson2
--- PASS: TestPhpToJson2 (0.00 seconds)
=== RUN TestPhpToJsonComplex
--- PASS: TestPhpToJsonComplex (0.00 seconds)
PASS
ok
_/Users/wuvist/source/gophpserialize 0.021s

31. Performance Tuning
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Python:
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from timeit import Timer ?!
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import cProfile ?

32. Go pprof
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http://blog.golang.org/profiling-go-programs

35. Productivity

36. •
go is just like python
•
•
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easy
concise
Yes, go needs more code than python
•
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Usually exception checking
Don’t really need to trade productivity for
performance & code quality

37. Dependency Management
Python
•

38. •
pip install MySQL-python
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may work, if you have the prerequisites
•
prerequisites are system wide
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MySQL-python is system wide
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So, vitualenv?

39. go
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go get = pip (kind of)
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gopath = per project virtualenv
!
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Both are built-in tools

40. Deployment
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Deploy python(Django?) project
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WSGI, FastCGI, SCGI, or AJP?
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python version?
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dependencies?

41. GO
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Copy & run the binary

42. Concurrency
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Python
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twisted
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gevent
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not as node.js’s callback hell, but…

43. Tornado
@gen.coroutine!
def fetch_json(url):!
response = yield AsyncHTTPClient().fetch(url)!
raise gen.Return(json_decode(response.body))!
http://www.tornadoweb.org/en/stable/
gen.html#tornado.gen.coroutine

44. gevent
>>> from gevent import monkey; monkey.patch_socket()!
>>> import urllib2 # it's usable from multiple greenlets now
http://www.gevent.org/intro.html#monkey-patching

45. •
How about MySQL-python/pylibmc?
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Do you really want monkey patch?
•
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Explicit is better than implicit. - Zen of python?
Or wait for python 3.4?
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beta 3, 26 January 2014

46. why not just go?

47. Q&A

48. Go tips
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Start with Go's official libs
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Look through their source code
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Consider use/create a framework
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http://beego.me

49. cool projects
!
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GroupCache
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Docker
•
raft
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beego

50. Gotcha
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Template support is poor
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Coding with static Type could be tedious
•
•
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No generic type
reflection is awful
JSON (parsing) is slow! Much slow than python
•
•
https://code.google.com/p/go/issues/detail?id=5683
Only fields with capital letters are exported