Php Dependency Management with Composer ZendCon 2016
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Php internal architecture
- 1. PHP Internal Architecture Pluggable, Extendable, Useable
- 2. Architecture PHP piece by piece
- 3. You should know the basics
- 4. All the puzzle pieces PHP Input/Output •SAPI •Streams Engine •Lexer •Parser •AST •Compiler •Executor Extensions •Zend Extensions •Compiled In •Loaded at startup •Loaded at runtime
- 5. Running PHP server makes request SAPI talks to engine engine runs SAPI returns output to server
- 6. How other languages do this Python (Cpython) • mod_python (embedded python interpreter, deprecated) • mod_wsgi (embedded or daemon) – basically a mod_python copy OR speaking to python interpreter with a special library installed via unix sockets) • command line interpreter • Fastcgi/cgi (using a library in python) Ruby (MRI) • also known as “CRuby” • Matz’s Ruby Interpreter • use Rack (library) to: • write/run a ruby webserver • use another server in between with hooks to nginx/apache (unicorn, passenger) • use FastCgi/Cgi
- 7. And still more.. NodeJS • Your app is your server • This is a pain • Write your own clustering or other neat features!! • So you stick a process manager in front • And you reverse proxy from apache/nginx • Or you use passenger or some other server…. Perl • Yes it still exists – shhh you in the back • PSGI + plack • mod_perl • mod_psgi
- 8. What makes PHP different? • Shared nothing architecture by design • application lifecycle is per-request • no shared state natively • infinite horizontal scalability in the language itself • HTTP is a first class citizen • You don’t need a library or framework • SAPI is a first class citizen • Designed to have a server in front of it • No library necessary • You don’t need a deployment tool to keep it all going
- 9. The answer to your question is
- 10. SAPI Server API – the least understood feature in PHP
- 11. What is a SAPI? • Tells a Server how to talk to PHP via an API • Server API • Server Application Programming Interface • “Server” is a bit broad as it means any type of Input/Output mechanism • SAPIS do: • input arguments • output, flushing, file descriptors, interruptions, system user info • input filtering and optionally headers, POST data, HTTP specific stuff • Handling a stream for the request body
- 12. In the beginning • CGI • Common gateway interface • Shim between web server and program • Simple • Stateless • Slow • Local • Good security with linux tools • Slow • Local • Programs can have too much access • Memory use not transparent (thrash and die!)
- 13. Then there was PHP in a Webserver • mod_php (apache2handler) • Run the language directly in the webserver, speaking to a webserver’s module api • Can access all of apache’s stuff • Webserver handles all the request stuff, no additional sockets/processes • It works well • Requires prefork MPM or thread safe PHP • Eats all your memories and never lets the system have it back • Makes apache children take more memory
- 14. CGI is slow: FastCGI to the rescue! • Persistent processes but CGI mad style • Biggest drawbacks? • “it’s old” • “I don’t like the protocol” • “it’s not maintained” • “other people say it’s not stable” • Apache fcgi modules do kind of suck • Nginx “just works” • IIS8+ “just works”
- 15. php-fpm – Make FastCGI better • FastCGI Process Manager • Adds more features than traditional FastCGI • Better process management including graceful stop/start • Uid/gid/chroot/environment/port/ini configuration per worker • Better logging • Emergency restart • Accelerated upload support • Dynamic/static child spawning
- 16. CLI? • Yes, in PHP the CLI is a SAPI • (Did you know there’s a special windows cli that doesn’t pop a console window?) • PHP “overloads” the CLI to have a command line webserver for easier development (even though it SHOULD be on its own) • PHP did that because fighting with distros to always include the cli-server would have meant pain, and if you just grab php.exe the dev webserver is always available • The CLI treats console STDIN/STDOUT as its request/response
- 17. php-embed • A thin wrapper allowing PHP to be easily embedded via C • Used for extensions in node, python, ruby, and perl to interact with PHP • Corresponding extensions do exist for those languages embedded in PHP
- 18. phpdbg • Wait – there’s a debugger SAPI? • Yes, yes there is
- 19. litespeed • It is a SAPI • The server just went open source… • I’ve never tried it, but they take care of the SAPI
- 20. Just connect to the app? • Use a webserver to reverse proxy to webserver built into a framework? • Smart to use a webserver that has already solved the hard stuff • But the app/web framework on top needs to deal with • HTTP keepalive? • Gzip with caching? • X-forwarded-for? Logging? Issues • Load balancing and failover? • HTTPS and caching? • ulimit? Remember we’re opening up a bunch of sockets!
- 21. Well, PHP streams can do that
- 22. Streams Input and Output beyond the SAPI
- 23. What is a Stream? • Access input and output generically • Can write and read linearly • May or may not be seekable • Comes in chunks of data
- 24. How PHP Streams Work Stream Contexts Stream Wrapper Stream Filter ALL IO
- 25. Definitions • Socket • Bidirectional network stream that speaks a protocol • Transport • Tells a network stream how to communicate • Wrapper • Tells a stream how to handle specific protocols and encodings
- 26. Built in Socket Transports • tcp • udp • unix • udg • SSL extension • ssl • sslv2 • sslv3 • tls
- 27. You can write your own streams! • You can do a stream wrapper in userland and register it • But you need an extension to register them if they have a transport • Extensions with streams include ssh, bzip2, openssl • I’d really like the curl stream back (not with the compile flag, but curl://)
- 28. Welcome to the Engine Lexers and Parsers and Opcodes OH MY!
- 29. Lexer • checks PHP’s spelling • turns into tokens • see token_get_all for what PHP sees
- 30. Parser + AST • checks PHP’s grammar • E_PARSE means “bad phpish” • creates AST
- 31. Compiler • Turns AST into Opcodes • Allows for fancier grammar • Opcodes can then be cached (opcache) skipping lex/parse/compile cycle
- 32. Opcodes • dump with http://derickrethans.nl/projects.html • machine readable language which the runtime understands
- 33. Engine (Virtual Machine) • reads opcode • does something • zend extension can hook it! • ??? • PROFIT
- 34. Extensions How a simple design pattern made PHP more useful
- 35. “When I say that PHP is a ball of nails, basically, PHP is just this piece of shit that you just put all the parts together and you throw it against the wall and it fucking sticks” - Terry Chay
- 36. So what is an extension? • Written in C or C++ • Compiled statically into the PHP binary or as a shared object (so/dylib/dll) • Provides • Bindings to a C or C++ library • even embed other languages • Code in C instead of PHP (speed) • template engine • Alter engine functionality • debugging
- 37. So why an extension? • add functionality from other languages (mainly C) • speed • to infinity and beyond! • intercept the engine • add debugging • add threading capability • the impossible (see: operator)
- 38. About Extensions • Types • Zend Extension • PHP Module • Sources • Core Built in • Core Default • Core • PECL • Github and Other 3rd Party
- 39. – “We need to foster a greater sense of community for people writing PHP extensions, […] Quite what this means hasn't been decided, although one of the major responsibilities is to spark up some community spirit, and that is the purpose of this email.” - Wez Furlong, 2003
- 40. What is PECL? • PHP Extension Code Library • The place for people to find PHP extensions • No GPL code – license should be PHP license compatible (LGPL is ok but not encouraged) • http://news.php.net/article.php?group=php.pecl.dev&article=5
- 41. PECL Advantages • Code reviews • See https://wiki.php.net/internals/review_comments • Help from other devs with internal API changes (if in PHP source control) • https://svn.php.net/viewvc?view=revision&revision=297236 • Advertising and individual release cycles • http://pecl.php.net/news/ • pecl command line integration • actually just integration with PEAR installer (which support binaries/compiling) and unique pecl channel • php.net documentation!
- 42. PECL Problems • Has less oversight into code quality • peclqa? • not all source accessible • no action taken for abandoned code • still has “siberia” modules mixed with “need a maintainer” • never enough help • tests • bug triaging • maintainers • code reviews • docs! • no composer integration • Half the code in git, half in svn still, half… elsewhere …
- 43. “It’s really free as in pull request” - me
- 44. My extension didn’t make it faster! • PHP is usually not the real bottleneck • Do full stack profiling and benchmarking to see if PHP is the real bottleneck • If PHP IS the real bottleneck you’re awesome – and you need to be writing stuff in C or C++ • Most times your bottleneck is not PHP but I/O
- 45. What about other languages? • Ruby gem • Will compile and install • Node’s npm • Will compile and install • Perl’s CPAN • Written in special “xs” language • Will compile and install • Python • Mixed bag? Distutils can install or grab a binary
- 46. FFI Talk C without compiling
- 47. What is FFI? • Foreign Function Interface • Most things written in C use libffi • https://github.com/libffi/libffi
- 48. Who has FFI? • Java calls it JNI • HHVM calls it HNI • Python calls it “ctypes” (do not ask, stupidest name ever) • C# calls it P/Invoke • Ruby calls it FFI • Perl has Inline::C (a bit of a mess) • PHP calls it…
- 49. FFI
- 50. Oh wait… • PHP’s FFI is rather broken • PHP’s FFI has no maintainer • It needs some TLC • There’s MFFI but it’s not done • https://github.com/mgdm/MFFI • Are you interested and not afraid?
- 51. For the future? • More SAPIs? • Websockets • PSR-7 • Other ideas? • Fix server-tests.php so we can test SAPIs • Only CGI and CLI are currently tested well • More extensions • Guidelines for extensions • Better documentation • Builds + pickle + composer integration
- 52. About Me http://emsmith.net auroraeosrose@gmail.com twitter - @auroraeosrose IRC – freenode – auroraeosrose #phpmentoring https://joind.in/talk/67433
