mirror of https://github.com/vbatts/talks.git
263 lines
4.6 KiB
Plaintext
263 lines
4.6 KiB
Plaintext
Intro to Golang
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05 December 2016
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Vincent Batts
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Developer
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@vbatts
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vbatts@redhat.com
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https://github.com/vbatts/talks
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* howdy
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$> finger $(whoami)
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Login: vbatts Name: Vincent Batts
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Such mail.
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Plan:
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right and joyful effort
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$> id -Gn
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devel redhat oci containers openshift slackware docker
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: Surview folks familiarity with golang. And with their primary language.
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* golang
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: Notes
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: - libraries - source only, but can link to C *.so and *.a
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: - Fork/Exec are coupled together (for coroutine and GC reasons)
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: - Threading, and multiproc, concurrent logic
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: -- nice and easy to use
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: -- Make for tricky handling of C calls (i.e. setns)
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: - `go get` is handy
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: - cross-compile without hardly any bootstrapping
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: -- native compiler supported arches
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: -- gccgo works for the arch gcc is compiled for
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: - primitives can seem a bit magical
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: -- conditional returns
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: -- for ... range
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: -- iota
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: - no ifdefs, but build tags
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: - error handling, rather than exception catching
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*
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.image ./gopher.png
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* Overview
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- strongly typed
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- compiled
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- stylistically nice
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- opinionated/idiomatic
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*
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.image ./rainbow.jpg
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* fully qualified imports
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.code ./imports.go /START1/,/STOP1/
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* fast compiles
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(Perhaps other compilers are slow)
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.play ./hello.go /START1/,/STOP1/
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* defer
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.code -numbers ./good0.go /START1/,/STOP1/
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* Garbage Collected
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- Super convenient
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- references
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- completed goroutines
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* Garbage Collected
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.link https://twitter.com/brianhatfield/status/634166123605331968 Brian Hatfield GC improvements
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- go1.4 (300ms) -> go1.5 (~30ms)
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- go1.6.0 (25ms) -> go1.6.3 (5ms)
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- go1.7.3 (3ms) -> go1.8beta1 (sub ms on 18Gb heap)
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* simple exports
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.code ./good1.go /START1/,/STOP1/
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* concurrency
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.play -numbers ./pingpong.go /STARTMAIN1/,/STOPMAIN1/
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.link http://talks.golang.org/2013/advconc.slide Sameer Ajmani - Advanced Concurrency
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* cross compiles
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: this could be demo'ed by scp'ing the binaries to fats.userys (aarch64) and piaba.usersys (arm v7)
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(staying away from CGO)
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.play ./hello.go /START1/,/STOP1/
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$> go build ./main.go
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$> file main
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main: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, not stripped
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$> GOOS=windows GOARCH=386 go build ./main.go
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$> file main.exe
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main.exe: PE32 executable (console) Intel 80386 (stripped to external PDB), for MS Windows
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$> GOOS=openbsd GOARCH=arm go build ./main.go
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$> file main
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main: ELF 32-bit LSB executable, ARM, version 1 (OpenBSD), statically linked, for OpenBSD, not stripped
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$> GOARCH=arm64 go build ./main.go
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$> file main
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main: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, not stripped
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* helpers
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- `go get golang.org/x/tools/cmd/godoc`
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- `go get github.com/golang/lint/golint`
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- https://github.com/fatih/vim-go
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- `go vet ./...`
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- `go test ./...`
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- `golint -set_exit_status ./...`
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*
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.image ./kanye_imma_bookmarklet.png 250 _
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.caption _kanye_ by Kayne
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- easy learning curve
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- `go get`
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- formatting wars are "over"
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- shared libraries
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*
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: they come along, and affect how you do your work
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.image ./cats20.gif
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.caption _halping_hooman_ by cat
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* Packaging
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Addresses different concern than distributions
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* lack of generics?
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: i don't feel strongly about this, though many do
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- interfaces - are enough for most
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- go1.4 introduced go:generate
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: produce code for Set, Graph etc, for the types needed, but at compile time. No need to reflect.
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* Debugging
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- gdb is there, sort of
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- some known debugging tools for ELF are not useful
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- fmt.Printf("%#v\n", ...)
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: show break on main.main and fmt.Println
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: continue, list, then step, then list, and then face melt
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* Concurrency and CGO
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Calls like setns(2) are rough
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(yes, even with runtime.LockOSThread())
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Embedding other languages (like ruby and python that have their green threading)
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* Fork/Exec
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Not Separate, but together
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*
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.image ./revenge-of-the-nerds-o.gif
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.caption _dancin'_ in ROTN
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* build tags
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no #ifdef
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.code ./tags.go /START1/,/STOP1/
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or files with *_linux.go like suffix.
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More like extern.
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* _
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bit bucket
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* channels
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.play ./ugly0.go /START1/,/STOP1/
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* iota
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.code ./ugly1.go /START1/,/STOP1/
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* for range
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array (or string)
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.play ./primitive1.go /START1/,/STOP1/
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* for range
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map
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.play ./primitive2.go /START1/,/STOP1/
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* for range
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channel (like an iterator)
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.play ./primitive3.go /START1/,/STOP1/
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* for range
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channel
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.code ./primitive3.go /START2/,/STOP2/
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* Conclusions?
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* use-case
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- like all languages, align with you use-case
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- get familiar enough to like and dislike it
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- don't be afraid to try it out
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* References
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.link https://golang.org/doc/ Go Documentation
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.link https://golang.org/doc/effective_go.html Effective Go
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