開発期間数年のサービスの完成間際にcontext対応をぶち込む / introduce context.Context into long term project

kamakura.go #5 @ 鎌倉

1. ࣮࿥ʂ։ൃظؒ਺೥ͷ
   αʔϏεͷ׬੒ؒࡍʹ
   DPOUFYUରԠΛͿͪࠐΉ LBNBLVSBHP
   
   
   !BDJEMFNPOɹ@
2. ͜Μʹͪ͸ʙ w ໘ന๏ਓΧϠοΫ
   ιʔγϟϧήʔϜࣄۀ෦
 ήʔϜٕݚ
   Ϧʔμʔ
 ֤ϓϩδΣΫτΛԣஅͰαϙʔτ͢ΔνʔϜ
   w ීஈ͸ओʹ(Pॻ͍ͨΓ1FSMॻ͍ͨΓ
 ௚ۙ͸$Λॻ͍͍ͯΔ 6OJUZ 
 &NBDT೿͚ͩͬͨͲ࠷ۙ74$PEF࢖ͬͯΔ
   w ח૔ࡏॅ
   Ո͔Β͜ͷձ৔·Ͱెา෼ !BDJEMFNPO
3. ࣄͷ࢝·Γ w ͋Β͢͡
   w ɹɹɹΑ͠
   ͍ͭ΋ͷΑ͏ʹෛՙࢼݧ͢Δͧ
   w ɹɹɹ"84
   93BZͰ෼ࢄτϨʔγϯάͩ
   ਺೥͔͚ͯ։ൃͨ͠(PͷαʔόϓϩάϥϜ͕ͦΖͦΖ
 αʔϏεΠϯ͢Δ͜ͱʹ
   ΊͰ͍ͨͰ͢Ͷʙ
4. 93BZͰ෼ࢄτϨʔγϯά w ૊௕ !GVKJXBSB ͷ:"1$5PLZP
   ͷൃදͳͲͰ͓ͳ͡Έ IUUQTTQFBLFSEFDLDPNGVKJXBSBZBQDUPLZP
   w ΧϠοΫͰ͸ࡢ೥͔Βෛՙࢼݧ΍ຊ൪؀ڥͷௐࠪʹ"84
   93BZΛ ར༻͍ͯ͠Δ
   w ૊௕͕࠷ॳʹೖΕͨࣄྫ͸1FSM͕ͩͬͨɺࠓճ͸(PϓϩμΫτ
 (PͳΒ"84͕4%,Λग़͍ͯ͠ΔͷͰࣗલͰϥΠϒϥϦ࡞ΔΈ͍ͨ ͳ͜ͱ͠ͳͯ͘΋େৎ෉
   ͜Ε͸উͬͨͳʜʜ
   ϑϥάͷཱͭԻ
5. 93BZ͸ԿΛ͢Δ͔ w 8FCαʔϏεʹ͓͚Δ͔͔࣌ؒΔཁૉͷՄࢹԽ
   w جຊతʹ֎෦*0 σʔλϕʔεɺ,74ɺ)551ͳͲʜ
   ͕͔࣌ؒ ͔Δॲཧ
   w ηάϝϯτΛ࡞ͬͯ։࢝࣌ؒͱ
 ऴྃ࣌ؒɺΤϥʔͳͲΛه࿥ͯ͠ૹΔ
   w "84͞ΜʹૹΓ͚ͭΔͱ͍͍ײ͡ʹ
 ՄࢹԽͯ͘͠ΕΔ
   ˠ͜Μͳײ͡ˠ
6. 93BZ
   4%,
   GPS
   (Pͷ৔߹
   DPOUFYUͷҾ͖ճ͠Ͱ࣮ݱ
7. ͜Μͳײ͡ w YSBZ$BQUVSFʹDUYͱ࣮ߦ͍ͨ͠ॲཧΛแΜͩؔ਺Λ౉͢ͱɺ $BQUVSF͕։࢝࣌ࠁͱऴྃ࣌ࠁΛDUYʹه࿥ͯ͘͠ΕΔ
 93BZ
   )551ΫϥΠΞϯτͳͲ͸಺෦Ͱ͜ΕΛ΍͍ͬͯΔ func criticalSection(ctx context.Context) { //this is an example of a subsegment xray.Capture(ctx, "GameModel.saveGame", func(ctx1 context.Context) error { var err error section.Lock() result := someLockedResource.Go() section.Unlock() xray.AddMetadata(ctx1, "ResourceResult", result) }) } IUUQTEPDTBXTBNB[PODPNKB@KQYSBZMBUFTUEFWHVJEFYSBZTELHPTVCTFHNFOUTIUNM
8. ͳΔ΄Ͳʜ w 93BZ
   4%,
   GPS
   (PΛ࢖͏ʹ͸DPOUFYU$POUFYU͕ඞཁ
   w ͜ͷϓϩδΣΫτ͸DPOUFYUᴈ໌ظʹ։ൃ͕ελʔτͨ͠ͷͰɺ%# ΞΫηε΍3FEJTૢ࡞ͷ෦෼ʹDPOUFYUΛར༻͍ͯ͠ͳ͍
   w ϦϑΝΫλϦϯάͯ͠DPOUFYUΛҾ͖ճ͍ͯ͘͠ඞཁ͕͋Δͳʜ
9. DPOUFYUҾ͖ճ͠ϦϑΝΫλ w 3FEJT
   w SFEJHPΛར༻͍ͯͯ͠ɺࣗલͷ3FEJT
   $MJFOUͰXSBQ͍ͯͨ͠ ͷͰͦͷҾ਺ʹ
   DPOUFYU$POUFYU
   Λ௥Ճ
 SFEJHP͸3FEJT
   $MVTUFSඇରԠͳͷͰޙʹHPSFEJTʹೖΕସ͑ͨ
   w 3FEJTͷ13
   
   —
   w 'MVFOU
   -PHHFS
   w ͜Ε΋ࣗલͰXSBQͯͨ͠ͷͰҾ਺ʹ
   DPOUFYU$POUFYU
   Λ௥Ճ
   w 'MVFOU
   -PHHFSͷ13
   
   —
10. ͦͷ΄͔ w )551ϦΫΤετ
    w ֎෦಺෦ؔ܎ͳ͘93BZ
    4%,ͷ)551
    $MJFOUʹࠩ͠ସ͑
    w "84ͷ֤छαʔϏε
    w 424
    
    4
    
    $MPVE4FBSDIͳͲͳͲ͸93BZ
    4%,ͰXSBQ ͯ͠ద༻Ͱ͖ΔΑ͏ʹͳ͍ͬͯΔ
    w ͜ͷลΛϞϩϞϩద༻ͯ͠
    
    —
11. ͜͜·Ͱ͸
    !LPOCPJ
    
    
    
    
    
    ͷ࢓ࣄ
    ϝϧϖΠʹస৬͍ͯͬͯ͠͠·ͬͨʜ
12. Ұ൪෺ྔ͋Γͦ͏ͳ
    %#ΞΫηεͷͱ͜Ζ͕
    ·ͩ࢒͍ͬͯΔ
13. ਓൈ͚ͯϓϩδΣΫτଆ͸େ๩͠
    
    Θͨ͠ͷग़൪ͩ
    @
14. %#ΞΫηεͷDPOUFYUରԠ w HPSN
    HJUIVCDPNKJO[IVHPSN
    Λར༻ͯͨ͠
    w ͦ΋ͦ΋HPSN͕DPOUFYUରԠ͍ͯ͠ͳ͍
    w W@EFW
    ϒϥϯνͰDPOUFYUରԠ։ൃͯ͠Δ͚Ͳఀ଺த
    w ʜͱ͸͍͑93BZ࢖͏ͷʹ%#ΞΫηεݟΒΕͳ͍ͷ͸ࠔΔ
    w ͍Ζ͍Ζௐࠪͯ͠Έͨ
15. 93BZ
    4%,͕༻ҙͯ͠Δ΋ͷ w 42-ͷτϨʔεʹ͍ͭͯͷυΩϡϝϯτ͕৴͡ΒΕͳ͍͘Β͍ബ͍
    w ΄Μͱʹ͜Ε͔͠ॻ͍ͯͳ͍
16. 93BZ
    4%,͕༻ҙͯ͠Δ΋ͷ w ॻ͍ͯ͋Δ͜ͱ
    ʮ͓·͑ΒͨͿΜ
    sql.Open
    Ͱ%#ϓʔϧ࡞ͬͯΔ Αͳ
    ͦΕΛ
    xray.SQL
    ʹ͢Ε͹͍͍͚ͩͩͥʯ
    w ͳΔ΄Ͳ
    ΍ͬͯΈͨ
    ˠ
    ίϯύΠϧΤϥʔ
    w γάωνϟΛ֬ೝ
    ˠ
    ໭Γ஋
    TRM%#
    ͡Όͳͯ͘
    YSBZ%#
    ͩʜ package xray func SQL(driver, dsn string) (*DB, error)
17. YSBZ%#ͩ w HPSN͸
    42-$PNNPO
    ͱ͍͏TRM%#ͷίϯςΩετͳ͠ϝιο υΛΠϯλϑΣʔεԽ͍ͯ͠Δ
    w YSBZ%#͸શ෦DUY෇͖ͰTRM%#ͷDUYϝιουΛ࣮૷͍ͯ͠Δ
    w ͭ·ΓΠϯλϑΣʔε͕ద߹͠ͳ͍ʜ type SQLCommon interface { Exec(query string, args ...interface{}) (sql.Result, error) Prepare(query string) (*sql.Stmt, error) Query(query string, args ...interface{}) (*sql.Rows, error) QueryRow(query string, args ...interface{}) *sql.Row } package xray func (db *DB) Exec(ctx context.Context, query string, args ...interface{}) (sql.Result, error) func (db *DB) Prepare(ctx context.Context, query string) (*Stmt, error) func (db *DB) Query(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error) func (db *DB) QueryRow(ctx context.Context, query string, args ...interface{}) *sql.Row HPSN YSBZ
18. ཧ૝ͱݱ࣮ w HPSNʹ౉͢TRM%#తͳԿ͔ʹࡉ޻Λͯ͠ɺHPSNΛXSBQͨ͠ϓ ϩδΣΫτͷ%#ΞΫηεΦϒδΣΫτ͔ΒͦͷDUYΛ஫ೖ͍ͨ͠
    w ͱʹ͔͍͘Ζ͍Ζ΍ͬͯΈ·͕ͨ͠ɺͰ͖·ͤΜͰͨ͠
 HPSN͕DPOUFYUରԠͯ͠ͳ͍ͷͰҾ͖ճ͕͠HPSNͰ෼அ͞Εͯ ͠·ͬͯ౉ͤͳ͍ʜ
    ΧελϜύϥϝʔλΛ౉͢ํ๏΋༻ҙ͞Εͯͳ͍
 &YFD2VFSZͷBSHTͷ࠷ॳʹDUY౉ͯ͠ϥούʔ͕෼཭͢Δࠇຐ๏Έ͍ͨͳ΍ͭ΋ࢼ͚ͨ͠Ͳͪΐͬͱແཧ͕͋ͬͨ
 ͋ͱɺTUSVDUͷϝϯόʹDUY࣋ͨͤΔํࣜ͸TRM%#΍HPSN͕දݱ͢Δ΋ͷ͸ίωΫγϣϯϓʔϧͰ͋ͬͯίωΫγϣϯ Ͱ͸ͳ͍ʜͱ͍͏͜ͱ͔ΒHPSPVUJOF
    TBGFʹͳΒͳ͍ͷͰ΍ͬͯ͸͍͚ͳ͍Ϡπ
19. ଥڠͨ͠ํ਑ w %#ΞΫηε෦෼͕DPOUFYUରԠͯ͠ྫ͑͹EFBEMJOFͱ͔DBODFM ͰΫΤϦதஅͰ͖ΔΑ͏ʹ͢Δͷ͸ʜఘΊΔ
    w HPSNΛXSBQͨ͠΋ͷΛ࡞ͬͯDUY͕౉ΔΑ͏ʹͯ͠ɺ93BZͷ $BQUVSF͚ͩ͸ͪΌΜͱ͢Δ
20. (PSNͷϥούΛ࡞ͬͯ࢓ࠐΉ w ಋೖखॱͱͯ͠͸͜Μͳ͔Μ͡
    HPSN%#
    ͷϝιουͷ͏ͪ࢖ͬͯΔ΍ͭΛશ෦ಉ͡γάωνϟ Ͱఆٛͯ͠ɺ·ͣ͸ίϯύΠϧΛ௨͢ த਎͸HPSNΛݺͿ͚ͩ
    ࣍ʹϥούͷୈҰҾ਺ʹશ෦
    ctx context.Context
    Λ௥Ճ͢Δ
    (PSNΛݺͼग़ͯ͠Δ෦෼Ͱຊ౰ʹେྔͷίϯύΠϧΤϥʔ͕Ͱ ΔͷͰɺͦΕΛશ෦௚͢
    93BZͷ$BQUVSFΛϥούʔʹ࢓ࠐΉ
    w ͱʹ͔͕͘େมͳ΍ͭͰ͢
21. ࣮ࡍͷ࡞ۀ
22. ࣗಈੜ੒ܥͷରԠ w ϦϦʔε௚લͷ͍·DUYೖΕͳ͔ͬͨΒ͍ΘΏΔٕज़తෛ࠴͕υΧʔϯͱͳ ΔΑͶʜ
    Έ͍ͨͳ͜ͱΛ13ίϝϯτʹॻ͍͍ͯͨ
    w ࣗಈੜ੒ܥ͸େͨۤ͠࿑ͯ͠ͳ͍͚ͲɺEJGG͸
     
    — 
23. ࢒Γͷ࡞ۀ w ͱʹ͔͘%#ݺͼग़͕͠େྔʹ͋ΔͷͰςΩετஔ׵ͳͲ΋ۦ࢖ͭͭ͠ ͣͬͱϦϑΝΫλϦϯάͯ͠ςετΛճ͍ͯͨ͠
    w ౰࣌ͷϝϞʹΑΔͱɺ$SFBUF
    
    %FMFUF
    
    &YFD
    
    'JOE
    
    'JSTU
    
    3BX
    
    4BWF
    ͷछͷϝιου͕߹ܭՕॴͰݺ͹Ε͍ͯΔ
    w Օॴશ෦खͰ௚ͯ͠ɺ͞Βʹݺͼग़͠ݩ͕DUY࣋ͬͯͳ͔ͬͨ Βͦ͜·ͰDUYΛҾ͖ճͨ͢Ίʹݺͼग़͠ݩΛ૎ͬͯDUY͕ग़ͯ͘Δ· ͰୈҰҾ਺ʹDUY௥Ճ͢Δ࡞ۀ
    w ͞Βʹɺςετ΋શ෦
    context.Background()
    ͯ͠౉͢࡞ۀ͕ඞཁ
24. ్தܦաͷ༷ࢠ w ҙ֎ͱͭΒ͘ͳͦ͞͏ʹݟ͑Δͷ͸ɺࣗ෼͕ϦϑΝΫλϦϯάେ޷͖ ਓ͔ؒͩΒ
    ๨೥ձ͔Βؼ͖ͬͯͯਲͬ෷͍ͳ͕ΒϦϑΝΫλϦϯά͢Δఔ౓ʹ͸େ޷͖
25. िؒ൒͔͔ͬͯແࣄ׬ྃ w HPSNΛXSBQ͢Δ࡞ۀͷຊਞϒϥϯν͸
     
    — 
    w ͜ΕͰҰ൪͕͔͔࣌ؒΔͱ͜Ζ͸͓ΘͬͨͷͰɺ93BZͷ$BQUVSF Λ࢓ࠐΜͰ͍͘
26. ϥούʔʹ$BQUVSFΛ௥Ճ w 93BZͷ$BQUVSFΛͦΕͧΕͷϝιουͰ΍Δ
    w ͜ͷํࣜͰ͸HPSN͕࣮ࡍʹ࣮ߦ͢Δ42-ΛऔΓग़ͤͳ͍ͨΊɺ୅ΘΓ ʹݺͼग़͠ͷҾ਺ͱίʔϧελοΫΛه࿥ // Exec ͩΑ func (g *GormDB) Exec(ctx context.Context, sql string, values ...interface{}) *GormDB { if seg := xray.GetSegment(ctx); seg == nil { return g.wrap(g.db.Exec(sql, values...)) } var res *GormDB tmp := []interface{}{sql} tmp = append(tmp, values...) caller := traceCaller("Exec", tmp...) xray.Capture(ctx, g.name, func(ctx context.Context) error { g.recordSQL(ctx, caller) res = g.wrap(g.db.Exec(sql, values...)) return res.Error }) return res } 93BZະ࢖༻࣌ 93BZ
    ࢖༻࣌
27. த਎ w ίʔϧελοΫͱ42-ͷBSHTΛه࿥
    w ه࿥෦෼͸93BZ
    4%,ͷ
    xray.DB.populate()
    Λࢀߟʹ func traceCaller(name string, args ...interface{}) string { pc, _, line, _ := runtime.Caller(2) f := runtime.FuncForPC(pc) return fmt.Sprintf("from %s(Line %d): %s(%s) ", f.Name(), line, name, argsString(args...)) } func (g *GormDB) recordSQL(ctx context.Context, info string) { seg := xray.GetSegment(ctx) typ := "master" if g.slave { typ = "slave" } seg.Lock() seg.Namespace = "remote" seg.GetSQL().ConnectionString = g.name seg.GetSQL().DatabaseType = typ seg.GetSQL().SanitizedQuery = info seg.Unlock() }
28. ແࣄ93BZରԠ׬ྃ w 93BZ
    4%,
    GPS
    (PͷYSBZ42-Λ࢖ͬͨͱ͖ͷΑ͏ʹ͸ߦ͔ͳ ͔͕ͬͨɺ࠷௿ݶ͔͔ͬͨ࣌ؒͱݺͼग़͍ͯ͠Δ৔ॴ಺༰͸Έ͑Δ Α͏ʹͳͬͨɻ͜ͷ13
    
    —
    w ࠓ΋ແࣄຊ൪؀ڥͰ93BZͷτϨʔε͕ಈ͍͍ͯ·͢
29. DPOUFYUʹ͍ͭͯ
    ͦͷଞͷ࿩୊
30. ΫϥΠΞϯτ੾அʹΑΔDBODFM w ΫϥΠΞϯτཁҼͳͷͰཧ༝͸Θ͔Βͳ͍͚ͲɺεϚϗΞϓϦͰ͸ͨ ·ʹඵͱ͔ͰϦΫΤετΛΩϟϯηϧ͢ΔΫϥΠΞϯτ͕͍Δ
    w %#ίϛοτޙͷϩάॻ͍ͯΔͱ͖ʹΫϥΠΞϯτཁҼͷDPOUFYU
    DBODFM͕ൃੜ͢Δ͜ͱ͕͋ͬͯɺࠔΔ
    w IUUQ4FSWFS͔ΒΩϟϯηϧ͞Εͳ͍΄͏͕͏Ε͍͠
31. ΫϥΠΞϯτ੾அʹΑΔDBODFM w ͦ΋ͦ΋ႈ౳ͳ࡞Γͷ"1*ʹͳ͍ͬͯΕ͹ɺαʔόʹϦΫΤετ͕དྷ ͨΒΫϥΠΞϯτʹؔ܎ͳ͘૸Γ͖ͬͨ΄͏͕Α͍
    w SFR
    
    SFR8JUI$POUFYU OFX$UY
    Ͱࠩ͠ସ͑Ͱ͖Δ
    w ϦΫΤετࣗମͷλΠϜΞ΢τ͸ඞཁͳͷͰɺSFRͷDUYΛܧঝͤͣ ʹDPOUFYU#BDLHSPVOE
    Ͱ৽͍͠ίϯςΩετΛ࡞ͬͯλΠϜ Ξ΢τΛઃఆ͢Δ
    w 4FSWFSΛ(SBDFGVMʹTIVUEPXO͢Δͷ͸ϦΫΤετλΠϜΞ ΢τ෼͘Β͍଴ͯ͹৽͍͠ϦΫΤετड͚෇͚ͳ͍ͷͰେৎ෉
32. ·ͱΊ
33. ·ͱΊײ૝ w ઌԆ͹͍ͯ͠͠Δͱޙ͔ΒϦϑΝΫλϦϯά͢Δίετ͕͍͢͝ࣄʹ ͳΔͷͰͬ͞͞ͱDPOUFYUରԠͨ͠΄͏͕Α͍
    w ࠓ͔Β։ൃΛ࢝ΊΔͳΒɺ࢖͍ͬͯΔ%#
    03.΍3FEJTΞΫηεͳ Ͳͷύοέʔδ͸DPOUFYUରԠ͍ͯ͠Δ΋ͷΛબͿ΂͖
 ٕज़બఆͷ༏ઌ౓ͱ͔ͯ͠ͳΓߴ͍ͱ͜ΖʹҐஔ͚ͮΔ΂͖
    w ઃܭํ਑ͱͯ͠ɺ ͨͱ͑ͦΕΛ࣮૷͢Δͱ͖͸࢖ͬͯͳͯ͘΋ ϩ δοΫతʹ֎෦ͷ*0͕͋Δ΋ͷ͸DPOUFYUΛ౉͓ͯ͘͠ͱΑ͍
 ͦ͏ͳΔͱ'MVFOUEͰϩάऔΔՄೳੑ͕͋Δͱ͜Ζ͸શ෦౉ͦ͏ʜͱͳΔ͚Ͳͦ͏͍͏΋Μͩ
34. ิ଍ ͕࣌ؒ͋Ε͹
35. ิ଍ w YSBZ42-
    ͱ
    DPOUFYUඇରԠ03.ͷ૬ੑʹ͍ͭͯɺ13ʹϝϞ͕ ͋ΔͷͰͦΕΛҾ༻
36. ิ଍ ͖ͭͮ w HPSN͔Β࣮ߦ͢Δੜͷ42-ΛऔΓग़ͯ͠93BZʹه࿥Ͱ͖ͳ͍ཧ༝
    w ิ଍͢ΔͱɺXSBQ͍ͯ͠ΔͷͰHPSNͷ࣮ମΛݺ͹ͳ͍ͱ8)&3&ͷ৚݅Λ૊Έཱ ͯͯ͘Εͳ͍ͷͰɺ࣮ମΛݺͿલʹه࿥Ͱ͖ͳ͍
 ࣮ମΛݺΜͩ͋ͱʹ஌Δํ๏͸ίʔϧόοΫͳΜ͚ͩͲͦΕʹDUY౉͢ํ๏͕ͳ͍ʜ