Intro. to Go Programming Language

Reasons People are Here

• Curious whether go is mature enough to be chosen for production
• Manipulate data with go
• Alternative to Python?
• Iz teh new hotness
• why compile anything when scripting languages are great
• Argue against the “here’s some crazy new thing we should try”
• Automation, TDD, tooling?
• Statically-typed compile-time, checking

Why give this talk

• History of building stuff. Http is how they communicate, but not really websites.
• Lots of machines doing stuff and generating data, but some people/groups want different data.
• Getting data from one place, ETLing it, and taking it to somewhere
• Before: used logstache: JRuby, but really slow, took a minute to spin up the JVM.
• Heard about Go, one of the benefits is that it’s a whole lot faster. It compiles down to binary executable. Helps avoid dependency hell because you can deliver an executable to ops team for deployment (and maybe some docs) [security caveat: if you have a dependency with security exploit, you have to redeploy the entire package).
• Written by Ken Thompson and Rob Pike of Unix and C lineage. Google asked them: if you would rewrite C today, here is some money, do it.
• Alternatives: Rust, Erlang, Haskell
• But Go is a very pragmatic language… was written for C and C++ programmers who actually have NOT flocked to Go. C++ gives way more power over stuff (though has a huge learning curve and potential to do things wrong), but if you’re already good at C++, why learn something new that is more controlled. Instead, Python/PHP/Ruby/Java folks are loving it because it’s not super abstract: there are good primitives, memory management (though you have control over GC).
• You can learn the Go language in a weekend and be productive in it in very little time.
• At least an order of magnitude performance benefit over Ruby/Python.
• The product that the Mozilla team decided to first try Go with is not a customer facing product. Backend, data-processing that replaces an existing system with exactly the same functionality. “If no one notices, we’ve done it right”. Can easily benchmark against the existing system. … and it has paid off!
• HEKA: https://github.com/mozilla-services/heka

How to Learn

• http://tour.golang.org
• Capital lettered functions are exported/public; lowercase are private to the package
• Everything is within one directory, but all functions can be arbitrarily moved within that directory (unlike python where filenames matter when importing).
• Tooling is great. Optimized for the developer experience.
• gofmt - will automatically format your code in the idiomatic manner; every single developer has this hooked up to format-on-save
• GDB works with Go for debugging. Bug because Go is compiled, you can’t interact dynamically with the current state
• Can return multiple variables from a function
• Not much metaprogramming
• There are no object hierarchies or inheritance trees. You can have a struct that has functions on it. It will automatically dereference pointers to structs, so you can write x.y.z where x is a struct, and the return value of y is another struct.

Concurrency

• Goroutines: concurrent processing
• Was initial concern that if something blew up in production, it would be tough to do post-mortem analysis to fix it
• Have yet to crash go program without a solid stack trace that doesn’t point to what broke
• Can run on multiple cores
• Channels: can send and receive values between goroutines. Automatically manages blocking and back-pressure.

Other stuff

• TDD, benchmarks: https://github.com/smartystreets/goconvey , gomock (ehh), gospec (smooth)
• Package Management: there are 17 different ones == none; cmake vs cgo
• Gorilla (pylons), Martini (more golike restful web framework)

Summary

• Go is badass multi-threaded, multi-process language
• Ruby/Python/PHP/Java programmers are loving it
• Has awesome interactive documentation at golang.org