RFCから読むHTTP/2の仕組みと速さの秘密

http://minteku.connpass.com/event/41262/
こちらの勉強会で発表した資料です。
HTTP/2の速さの秘密を、RFCを読み解いて解説します。
内容は主にストリームとフレームについて。

1. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έ ͱ଎͞ͷൿີ
2. yusuke.saito.1982 RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ࣗݾ঺հ ▸ ᴡ౻ ༞ีʢ͍͞ͱ͏ɹΏ͏͚͢ʣ ▸ גࣜձࣾΏΊΈɹCTO / ࠷ߴٕज़੹೚ऀ ▸ ͜ΜͳΜͰ͕͢झຯ͸ߚ஡ͱฤΈ෺Ͱ͢ ▸ ޷͖ͳ৭͸ΦϨϯδ
3. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ຊ೔ͷλʔήοτ ▸ HTTPʹ͍ͭͯͷجຊతͳ஌ࣝ͸͋ΔํΛ૝ఆ͍ͯ͠·͢ɻ ▸ RFCΛಡΈ׳Ε͍ͯͳͯ͘΋େৎ෉Ͱ͢ɻ ▸ ΋͠෼͔Βͳ͍఺͕͋Ε͹ɺ࠷ޙʹ࣭ٙԠ౴͕͋Γ·͢ɻ
4. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ࠓ೔ͷ಺༰ ▸ RFC͸ා͘ͳ͍ʂ ▸ RFCͷಡΈํ ▸ HTTP/2ͷRFCΛಡ΋͏ʂ
5. RFC͸ා͘ͳ͍
6. RFC…
8. RFC͸ಡΈํͷίπΛ஌͍ͬͯΕ͹ಡΊ·͢ʂ
9. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ RFCͷಡΈํ ▸ ͱΓ͋͑ͣਂݺٵͯ͠ɺ໨࣍ΛಡΈ·͠ΐ͏ ▸ ஌Γ͍ͨ͜ͱʹؔ࿈ͦ͠͏ͳষΛ୳͠·͠ΐ͏ ▸ ֤ষͷ࠷ॳʹɺͦͷষͷઆ໌͕͋ΔͷͰɺಡΈ·͠ΐ͏ʂ ▸ ৄ͍͠࿩ΛಡΈ͚ͨΕ͹ɺষͷதΛಡΈ·͠ΐ͏ʂ ▸ ࠓ೔΋ɺͦͷಡΈํʹै͍͖͍ͬͯͨͱࢥ͍·͢
10. HTTP/2ͷRFCΛಡ΋͏ʂ
11. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ࢿྉ ▸ RFC 7540
 https://tools.ietf.org/pdf/rfc7540.pdf ʲݪจʳ
 https://summerwind.jp/docs/rfc7540/ ʲ೔ຊޠ൛ʳ
 ɹ※Ұ෦༁จʹ໰୊͕͋Δ৔߹͕͋Γɺຊ೔Ҿ༻͸͍ͯ͠·ͤΜɻ

12. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ໨࣍Λಡ΋͏ 1. Introduction 2. HTTP/2 Protocol Overview 3. Starting HTTP/2 4. HTTP Frames 5. Streams and Multiplexing 6. Frame Definitions 7. Error Codes 8. HTTP Message Exchanges 9. Additional HTTP Requirements/ Considerations 10.Security Considerations 11.IANA Considerations 12.References
13. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ͳΜͱͳ͘౰ͨΓΛ͚ͭΔ 1. Introduction 2. HTTP/2 Protocol Overview 3. Starting HTTP/2 4. HTTP Frames 5. Streams and Multiplexing 6. Frame Definitions 7. Error Codes 8. HTTP Message Exchanges 9. Additional HTTP Requirements/ Considerations 10.Security Considerations 11.IANA Considerations 12.References
14. 1. INTRODUCTION
15. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ
16. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP1.1ͷ௨৴ͷ࢓ํ͸ྑ͘ͳ͍ʂ HTTP1.0͔ΒHTTP1.1΁վྑͨ͠ͷ͸෼͔Δɻ͕ͩμϝͩʂ
17. ໰୊఺̍ɿ௨৴ͷඇޮ཰
18. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ Client Server GET xxxxx.html GET XXX.jpg GET YYY.jpg : TCP Connection HTTP1.0
19. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP1.1 KEEP-ALIVE Client Server GET xxxxx.html GET XXX.jpg GET YYY.jpg : TCP Connection
20. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP1.1 KEEP-ALIVE PIPELINING Client Server GET xxxxx.html GET XXX.jpg GET YYY.jpg : TCP Connection GET ZZZ.jpg
21. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP1.1 KEEP-ALIVE PIPELINING Client Server GET xxxxx.html GET XXX.jpg GET YYY.jpg : TCP Connection GET ZZZ.jpg ॏ͍
22. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP1.1 KEEP-ALIVE PIPELINING Client Server GET xxxxx.html GET XXX.jpg GET YYY.jpg : TCP Connection GET ZZZ.jpg ॏ͍ HEAD OF LINE BLOCKING
23. ໰୊఺̎ɿ௨৴Ϧιʔεͷແବ
24. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP1.1
 (RFC 2616) A single-user client SHOULD NOT maintain more than 2 connections with any server or proxy.
25. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ࣮ࡍ
26. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP1.1 (RFC 7230) As a result, this specification does not mandate a particular maximum number of connections but, instead, encourages clients to be conservative when opening multiple connections.
27. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP1.1 (RFC 7230) As a result, this specification does not mandate a particular maximum number of connections but, instead, encourages clients to be conservative when opening multiple connections. ຊ࢓༷Ͱ͸ಛఆͷ઀ଓ਺ͷ্ݶΛٛ຿෇͚ͳ͍͕ɺΫϥΠΞϯτ͸ ෳ਺઀ଓΛ͢Δ͜ͱʹอकతͰ͋Δ͜ͱΛਪ঑͢Δɻ
28. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP1.1 (RFC 7230) As a result, this specification does not mandate a particular maximum number of connections but, instead, encourages clients to be conservative when opening multiple connections. ຊ࢓༷Ͱ͸ಛఆͷ઀ଓ਺ͷ্ݶΛٛ຿෇͚ͳ͍͕ɺΫϥΠΞϯτ͸ ෳ਺઀ଓΛ͢Δ͜ͱʹอकతͰ͋Δ͜ͱΛਪ঑͢Δɻ ఘΊ΍͕ͬͨʂ
29. ղܾࡦ
30. ௨৴ͷޮ཰Λ্͛Ε͹OKʂ ※ޮ཰͕े෼ߴ͚Ε͹ෳ਺઀ଓ͸͠ͳͯ͘Α͍ɻ
31. HTTP/2ͷ౴͑Λ ઌʹνϥݟͤ
32. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2ͷத৺֓೦ ▸ίωΫγϣϯ ▸ετϦʔϜ ▸ϑϨʔϜ
33. ίωΫγϣϯɺετϦʔϜɺ ϑϨʔϜͷؔ܎
34. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ CONNECTION (TCP)
35. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ CONNECTION STREAM STREAM STREAM STREAM STREAM
36. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ STREAM FRAME FRAME FRAME FRAME
37. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2ͷϙΠϯτ ▸ 1ͭͷίωΫγϣϯͷதͰɺෳ਺ͷϦιʔεͷ΍ΓऔΓΛ· ͱΊͯߦ͏ ▸ ͦΕͧΕͷϦιʔεͷ΍ΓऔΓ͸ɺʮετϦʔϜʯͱ͍͏୯ ҐͰ۠ผ͢Δɹ→HTTP/1.1ͰͷʮίωΫγϣϯʯʹ͍ۙ ▸ ͦΕͧΕͷετϦʔϜͷதͰ͸ɺʮϑϨʔϜʯͱ͍͏୯ҐͰ ௨৴Λߦ͏ɹ→HTTP/1.1Ͱͷʮϝοηʔδʯʹ͍ۙ
38. ͦΕΛ౿·͑ͯ
39. 2. HTTP/2 PROTOCOL OVERVIEW
40. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ
41. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ͜ͷηΫγϣϯ͸ɺHTTP/2ͷશ๴Λ·ͱΊ͍ͯ·͢ɻ ύϥάϥϑ͝ͱʹઆ໌͍ͨ͠·͢ɻ
42. ·ͩઆ໌Λ͍ͯ͠ͳ͍ࣄ߲͕ଟ͍ͷͰɺ Α͘෼͔Βͳ͍΋ͷ͸ʮͦ͏͍͏΋ͷ͕͋ΔΜͩʯ ͱҰ୴ड͚ೖΕ͓͍͍ͯͯͩ͘͞ɻ
43. ֓ཁ
44. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2ϓϩτίϧͷ֓ཁ ▸ HTTP/2͸సૹΛ࠷దԽ͢Δ ▸ HTTP/2͸HTTP/1.1ͷओཁͳػೳΛશͯαϙʔτ͢Δ
45. ϑϨʔϜ
46. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2ϓϩτίϧͷ֓ཁ ▸ HTTP/2ͷجຊ୯Ґ͸ʮϑϨʔϜʯ(Section 4.1) ▸ ֤ϑϨʔϜλΠϓ͸ҟͳΔ໨తΛՌͨ͢ ▸ HEADERS ͱ DATA ϑϨʔϜ͸ HTTP ϦΫΤετͱϨεϙϯ ε Λߏ੒͢Δ (Section 8.1) ▸ SETTINGS, WINDOW_UPDATE, PUSH_PROMISEͱ͍ͬͨ ϑϨʔϜ͸HTTP/2ͷผͷػೳʹ࢖ΘΕΔ
47. ετϦʔϜ
48. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2ϓϩτίϧͷ֓ཁ ▸ ϦΫΤετͷଟॏԽ͸֤HTTPͷϦΫΤετʗϨεϙϯεΛ ֤ετϦʔϜʹׂΓ౰ͯΔ͜ͱͰ࣮ݱ͢Δ (Section 5) ▸ ετϦʔϜ͸ͦΕͧΕ͓͓Αͦಠཱ͍ͯ͠Δ ▸ ϦΫΤετ΍Ϩεϙϯε͕ࢭ·ͬͯ΋ɺଞͷετϦʔϜʹ͸ ӨڹΛ༩͑ͳ͍
49. ϑϩʔ੍ޚ
50. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2ϓϩτίϧͷ֓ཁ ▸ ϑϩʔ੍ޚͱ༏ઌ౓෇͚ͰଟॏԽ͞ΕͨετϦʔϜΛޮ཰త ʹ࢖༻͢Δ ▸ ϑϩʔ੍ޚʹΑͬͯɺϢʔβ͕ඞཁͳσʔλͷΈసૹ͢Δ (Section 5.2) ▸ ༏ઌ౓෇͚ʹΑͬͯɺ΋ͬͱ΋ॏཁͳετϦʔϜʹϦιʔε Λ࠷༏ઌͰׂΓ౰ͯΔ (Section 5.3)
51. αʔό ϓογϡ
52. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2ϓϩτίϧͷ֓ཁ ▸ HTTP/2͸αʔό͕ΫϥΠΞϯτʹϨεϙϯεΛϓογϡ͢Δɺ৽ ͍͠ର࿩ϞʔυΛ௥Ճ (Section 8.2) ▸ ΫϥΠΞϯτ͕ඞཁʹͳΔσʔλΛ༧ଌͯ͠ΫϥΠΞϯτʹૹΔ ͜ͱ͕ग़དྷΔ ▸ αʔό͸PUSH_PROMISEϑϨʔϜͷϦΫΤετΛ߹੒ͯ͠ૹ৴͢ Δ ▸ αʔό͸ͦͷϦΫΤετʹର͢ΔϨεϙϯεΛผετϦʔϜͰૹ ৴͢Δ
53. ϔομѹॖ
54. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2ϓϩτίϧͷ֓ཁ ▸ HTTPϔομʹ͸ଟ͘ͷ৑௕ͳσʔλؚ͕·ΕΔͷͰɺͦΕ ΛؚΉϑϨʔϜ͸ѹॖ͞ΕΔ (Section 4.3)
55. Section 2 આ໌จ͸͜͜·ͰͰ͢
56. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2ͷϙΠϯτʢ࠶ܝʣ ▸ 1ͭͷίωΫγϣϯͷதͰɺෳ਺ͷϦιʔεͷ΍ΓऔΓΛ· ͱΊͯߦ͏ ▸ ͦΕͧΕͷϦιʔεͷ΍ΓऔΓ͸ɺʮετϦʔϜʯͱ͍͏୯ ҐͰ۠ผ͢Δɹ→HTTP/1.1ͰͷʮίωΫγϣϯʯʹ͍ۙ ▸ ͦΕͧΕͷετϦʔϜͷதͰ͸ɺʮϑϨʔϜʯͱ͍͏୯ҐͰ ௨৴Λߦ͏ɹ→HTTP/1.1Ͱͷʮϝοηʔδʯʹ͍ۙ
57. ࠓ೔͸ϑϨʔϜͱετϦʔϜʹߜͬͯઆ໌͠·͢ɻ ϑϩʔ੍ޚɾαʔόϓογϡʹ͍ͭͯ͸ࠓճ͸৮Ε·ͤΜɻ
58. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ॻ͍ͯ͋ͬͨ͜ͱ ▸ ετϦʔϜͰϦΫΤετɾϨεϙϯεΛଟॏԽग़དྷΔ ▸ ϑϨʔϜͰϦΫΤετɾϨεϙϯεΛߏ੒͢Δ
59. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ౰ͨΓΛ͚ͭΔʢ̎౓໨ʣ 1. Introduction 2. HTTP/2 Protocol Overview 3. Starting HTTP/2 4. HTTP Frames 5. Streams and Multiplexing 6. Frame Definitions 7. Error Codes 8. HTTP Message Exchanges 9. Additional HTTP Requirements/ Considerations 10.Security Considerations 11.IANA Considerations 12.References
60. 4. HTTP FRAMES
61. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ
62. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ϑϨʔϜͷλΠϓ ετϦʔϜࣝผࢠ
63. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ϑϨʔϜͷλΠϓ ▸ ৄࡉ͸ Section 6 ʹͯఆٛ͞Ε͍ͯΔ
64. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ
65. 5. STREAMS AND MULTIPLEXING
66. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ
67. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ 1ͭͷHTTP/2ίωΫγϣϯ͸ෳ਺ͷ։͍ͨετϦʔϜΛ࣋ͪɺ૒ํ ͕ෳ਺ͷετϦʔϜͰϑϨʔϜΛ΍ΓऔΓग़དྷΔ ετϦʔϜ಺Ͱૹ৴͢ΔϑϨʔϜͷॱং͸ॏཁɻ ετϦʔϜ͸੔਺஋Ͱ۠ผ͢Δɻ
68. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ CONNECTION ݱ࣮ʹωοτϫʔΫʹྲྀΕΔσʔλ :3 ID:2 ID:2 ID:1 ID:1 ID:2 ID:2 ID:1
69. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ CONNECTION ݱ࣮ʹωοτϫʔΫʹྲྀΕΔσʔλ
70. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ CONNECTION σʔλͷղऍ STREAM ID:1 STREAM ID:2 STREAM ID:3 STREAM ID:4 STREAM ID:5 STREAM ID:6
71. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ CONNECTION σʔλͷղऍ STREAM ID:1 STREAM ID:2 STREAM ID:3
72. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ CONNECTION STREAM ID:1 σʔλͷղऍ STREAM ID:2 STREAM ID:3 ID:2 ID:2 ID:1 ID:1 ID:1
73. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ CONNECTION STREAM ID:1 σʔλͷղऍ STREAM ID:2 STREAM ID:3 ID:2 ID:2 ID:3 ID:3 ID:3
74. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ
75. 8. HTTP MESSAGE EXCHANGES
76. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ
77. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2Ͱ͸ݱࡏ࢖༻͍ͯ͠ΔHTTPͱՄೳͳݶΓޓ׵ʹͨ͠

78. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ݁ہͷͱ͜Ζ ▸ HTTP/1.1ͷ࢓༷͸େ෦෼ҡ࣋͞ΕΔ ▸ Message Syntax and Routing [RFC7230] ͷҰ෦ ▸ Semantics and Content [RFC7231] ▸ Conditional Requests [RFC7232] ▸ Range Requests [RFC7233] ▸ Caching [RFC7234] ▸ Authentication [RFC7235]
79. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ มΘΔͷ͸ʁ ▸ ௨৴ͷํ๏ͷΈʂ ▸ ϦΫΤετɾϨεϙϯε͕ετϦʔϜ্ͰͲͷΑ͏ʹදݱ͞ Ε͍ͯΔͷ͔͕෼͔Ε͹ɺHTTP/2ͷ௨৴͕෼͔Δʂ
80. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ 8.1.3 Examplesɹ̍ϑϨʔϜͰ׬݁͢ΔϦΫΤετ
81. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ 8.1.3 Examplesɹ̍ϑϨʔϜͰ׬݁͢ΔϦΫΤετ ͜ΕҎ্ϔομ͸ͳ͍Ͱ͢Α
82. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ 8.1.3 Examplesɹ̍ϑϨʔϜͰ׬݁͢ΔϦΫΤετ ͜ΕҎ্ϔομ͸ͳ͍Ͱ͢Α ฦࣄૹͬͯ͘ΕͨΒ͜ͷετϦʔϜ ͸ด͍͍ͯ͡Ͱ͢Α
83. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ 8.1.3 ExamplesɹϨεϙϯεʢHEADERSͷΈͷ৔߹ʣ
84. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ 8.1.3 ExamplesɹϨεϙϯεʢσʔλ͕͋Δ৔߹ʣ
85. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ 8.1.3 ExamplesɹPOSTϦΫΤετ
86. ·ͱΊ
87. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ HTTP/2͕εΰ͍ͷ͸ ▸ ௨৴Λޮ཰Խ͢ΔɺετϦʔϜͷ࢓૊Έ͕εΰ͍ʂ
 Section 4, 5 ▸ HTTP/1.1ͷجຊΛҡ࣋ͯ͠ޮ཰͚ͩΛߟ͑ͨͷ͕εΰ͍ʂ
 Section 8.1
88. RFC͔ΒಡΉHTTP/2ͷ࢓૊Έͱ଎͞ͷൿີ ͦͷଞͷ࿩୊ ▸ ࠓ೔৮Εͳ͔ͬͨ෦෼ʹ͍ͭͯ ▸ ετϦʔϜͷ༏ઌ౓੍ޚ
 Section 5.3 ▸ αʔόϓογϡؔ࿈
 Section 8.2 ▸ ηΩϡϦςΟؔ࿈ࣄ߲
 Section 10