Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ SPRINGONE2GX WASHINGTON, DC HTTP/2 for the web developer By Brian Clozel @brianclozel
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Hello! @brianclozel Spring Framework committer Sagan lead developer 2
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Too Long; Didn’t Attend 1. HTTP/2 is about solving latency issues, but also introduces features with new possibilities 2.It retains the semantics of HTTP 1.1, but dev + ops need to evolve 3. Server Push & Stream prioritization are more complex than one might think 4. Support is on its way, adoption rate is great, but still questions on deployment options & implementations 3
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ What’s wrong with HTTP 1.1? 4
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP 1.1 is here to stay RFC 2616 is now obsolete RFC 7230-7235 5
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP 1.1 issues • Sending redundant info in HTTP headers • Privacy • UPGRADE to other protocols 6
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP 1.1 issues - Head of line blocking 7 Client Server Request #1 Response #1 Request #2 Response #2
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Head of line blocking More TCP connections/ domain? Domain sharding? 8
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Improving page load time Bandwidth vs. Latency 12
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Problems with HTTP 1.1 workarounds 13
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Domain sharding • No magical number • Cost of DNS queries • TCP slow start 14
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Concatenation • cache efficiency/invalidation • client performance • client build more complex 15
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Protocol basics 1/6 A single TCP connection 18
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Protocol basics 2/6 Multiple Streams 19
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Protocol basics 3/6 Binary Framing 20
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Streams 21 Client Server Stream: 3 HEADERS Stream: 5 HEADERS Stream: 5 DATA Stream: 3 HEADERS Stream: 3 DATA Stream: 5 HEADERS Stream: 3 DATA
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Protocol basics 4/6 Flow Control 22
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Protocol basics 5/6 HPACK (header compression) 23
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Header table 24 id name value 12 :path /index.html
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Static + dynamic tables 25 Client Server
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Protocol basics 6/6 TLS (not) required 26
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP/2 with Spring Boot + Jetty 28
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ With undertow! 29 Source: https://github.com/making/demo-http2
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ SSL Keylog file in Wireshark 32
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP/2 support & adoption 33
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Server implementations (native) • Apache Traffic Server • Nginx (alpha patch) • apache httpd (mod_h2) • h2o • nghttp2.org 34
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ On the JVM • Undertow • Jetty • Netty • OkHttp • Tomcat 9 (WIP) 35
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Application Layer Protocol Negotiation • protocol negotiation in TLS handshake • formerly NPN • vs. protocol Upgrade in HTTP 1.1 • your SSL/TLS implementation must support it 36
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ALPN and JDK support • JDK6 only supports TLSv1 • JDK7 supports TLSv1.2 • JDK8 supports TLSv1.2 (default) • JDK9 will support ALPN • Note: JSSE ciphers support… 37 Source: https://blogs.oracle.com/java-platform-group/entry/diagnosing_tls_ssl_and_https
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ ALPN support with JDK7 and JDK8 • using jetty-alpn.jar • overrides sun.security.ssl.{ClientHandshaker,ServerHandshaker} • java -Xbootclasspath/p:<path_to_alpn_boot_jar> … • jar version compatibility check with JDK version 38 Source: https://blogs.oracle.com/java-platform-group/entry/diagnosing_tls_ssl_and_https
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ JDK9 improvements • ALPN support (work in progress) • cipher updates • HTTP/2 Client • replace HTTPUrlConnection • async notifications on headers, body, server push… • CompletableFuture and lambdas 39 JEP 110: https://bugs.openjdk.java.net/browse/JDK-8042950
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Servlet 4.0 • Servlet 3.1 shipped with async IO • Supporting http/2 additional capabilities (stream prioritization & server push APIs) • Considering Reactive Streams support and java.util.concurrent.Flow 40 Source: https://java.net/projects/servlet-spec/lists/jsr369-experts/archive/2015-08/message/1
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP/2 Flow Control 42 Client Server Stream: 5 HEADERS Stream: 5 DATA Stream: 5 DATA Stream: 5 WINDOW_UPDATE xx octets
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Differentiating features • IO & programming model • Optional features in HTTP/2 • Server Push • Stream prioritization • Proxy capacities 43
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP/2 browser support 44 Source: caniuse.com
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP/2 browser support (market share) 45 Source: caniuse.com
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Pre-flight HTTP/2 checklist (6 steps) 47
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Step 1: Improve TCP support on servers • Upgrade Linux kernels to 3.2+ • Set Initial Congestion Window to 10 segments • TCP Fast Open support • Proportional Rate Reduction 48
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Step 2: Enforce HTTP 1.1 best practices • Cache-Control and ETag headers • gzip/deflate • image compression / media queries • get ready to remove HTTP 1.1 workarounds 49
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Step 4: Secure your application with TLS • New requirements for certificates: SHA256 RSA, 2048bits • TLS v1.2 (limited list of ciphers) • h2c won’t really help here • letsencrypt.org 51
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Step 5: Undo HTTP1.1 workarounds? • Most of those are harmful when applied to HTTP/2 • What about supporting both HTTP 1.1 & HTTP/2 52
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Step 6: Update your development toolset • Web developer tools, Wireshark, NSSKeyLog • Test your app with latency! 53
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Push_Promise 55 Client Server Stream: 5 HEADERS GET /resource Stream: 5 PUSH_PROMISE Promised Stream: 8 GET /other Stream: 8 DATA Stream: 5 HEADERS Stream: 8 HEADERS
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP/2 Server Push // Latency solved! Off to the pub! @HttpPush("/*.css", "/*.js") public void myControllerHandler() { // Some code here } 56
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Push Promise: order of frames « The server SHOULD send PUSH_PROMISE (Section 6.6) frames prior to sending any frames that reference the promised responses. This avoids a race where clients issue requests prior to receiving any PUSH_PROMISE frames. » 58 Source: https://httpwg.github.io/specs/rfc7540.html#rfc.section.8.2.1.p.1
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Push_Promise: order of frames 59 Client Server Stream: 5 HEADERS GET /index Stream: 5 PUSH_PROMISE Promised Stream: 8 GET /main.css Stream: 5 DATA Stream: 5 HEADERS Stream: 11 HEADERS GET /main.css Duplicate!?!
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Server push; code example @Override public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException { // Pushing resources here chain.doFilter(req, resp); // Too late? } 60
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Jetty PushCacheFilter • Use the « Referer » HTTP header • Maintain a Map of page -> List of resources • Automatically pushing associated resources • Limits? 61
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Is pushing everything really efficient? • Only when page loaded with empty cache? • Resources already cached? • All pushed resources necessary for initial render? Or app ready to be used? • Maintain the list of resources to push manually? • Aren’t we denying all browser heuristics? 62
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ So what do we need? • Private browser info: cache state, CPU, battery • Knowledge of Browser internals (layout, painting?) • Could we have priority information for each resource? 63
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Stream dependency / weight 65 Stream: 11 HEADERS Dependency: 8 Weight: 55 GET /other
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Resource Dependency Tree (in theory) 66 Stream 0 S1;W12 S2;W50 S3;W34 S4;W20 S5;W20
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Is this enough? • Is there a way to manually set a priority on a resource? • So HTTP/2 Server Push is the only mechanism to improve latency? • This works only for our own resources, what about 3rd party resources like fonts, JavaScript libraries? 69
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Server Push with Spring Boot + Jetty 70
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Resource Hints: a W3C draft Assisting User Agents in their decision process of fetching resources. http://w3c.github.io/resource-hints/ 72
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Resource Hints, HTML markup <!DOCTYPE html> <html> <head> <!-‐-‐ resolve DNS as early as possible -‐-‐> <link rel="dns-‐prefetch" href="//example.org"></script> <!-‐-‐ dns-‐prefetch + TCP handshake -‐-‐> <link rel="preconnect" href="//example.org" /> </head> <body> </body> </html> 73
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Resource Hints browser support 76
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Comparing with HTML5 async/defer <!DOCTYPE html> <html> <head></head> <body> <!-‐-‐ loading asynchronously, executing as soon as possible -‐-‐> <script src="/app.js" async></script> <!-‐-‐ loading & executing after page load -‐-‐> <script src="/other.js" defer></script> </body> </html> 78
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Performance: combining strategies is the key We need to consider: • Server implementation • Browser capabilities • HTTP/2 features • front-end « optimization » • Hosting Infrastructure 80
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Clever Proxies 81 Client Server Proxy 1) HTML + Resource Hint 2) Resource fetch 2) HTML + Server push
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Packaging your app with ALPN • Snowflakes in production? • Repeatable staging • Runtime support with Cloud Foundry buildpacks? 83
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Distributing secrets… Making certs+keys available in a distributed environment: • Spring Cloud Config server? • Tools for managing secrets (Vault?) 84
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ Apple Push Notification Service 85 Provider APNS Feedback APNS HTTP 1.1 polling for feedback
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HTTP/2 chosen for next version of APNS 86 Provider APNS HTTP/2
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ HAL + Server Push { ... "_links": { "self": { "href": "/issue/123456" }, "assigned": { "href": "/user/bclozel" } } } 88 Push this resource?
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ https://github.com/bclozel/http2-experiments 89
Inc. and licensed under a Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/ 90 Enjoy SpringOne2GX! Don’t miss « Introduction to Reactive Programming » - 10:30AM, this room Learn More. Stay Connected. @springcentral Spring.io/video
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