{"id":31124,"date":"2019-10-31T21:39:36","date_gmt":"2019-10-31T18:39:36","guid":{"rendered":"https:\/\/prohoster.info\/blog\/stroitelnye-bloki-raspredelennyh-prilozhenij-vtoroe-priblizhenie\/"},"modified":"2019-10-31T21:39:36","modified_gmt":"2019-10-31T18:39:36","slug":"stroitelnye-bloki-raspredelennyh-prilozhenij-vtoroe-priblizhenie","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sq\/blog\/administrirovanie\/stroitelnye-bloki-raspredelennyh-prilozhenij-vtoroe-priblizhenie","title":{"rendered":"Blloqet e nd\u00ebrtimit t\u00eb aplikacioneve t\u00eb shp\u00ebrndara. Qasja e dyt\u00eb","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Njoftim<\/strong><\/p>\n

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T\u00eb dashur koleg\u00eb, n\u00eb mesin e ver\u00ebs planifikoj t\u00eb publikoj nj\u00eb cik\u00ebl tjet\u00ebr artikujsh mbi projektimin e sistemeve t\u00eb sh\u00ebrbimit masiv: \u201cEksperiment VTrade\u201d \u2014 nj\u00eb p\u00ebrpjekje p\u00ebr t\u00eb shkruar nj\u00eb korniz\u00eb p\u00ebr sistemet tregtare. N\u00eb k\u00ebt\u00eb cik\u00ebl do t\u00eb shqyrtohet teoria dhe praktika e nd\u00ebrtimit t\u00eb nj\u00eb tregu, ankandi dhe dyqani. N\u00eb fund t\u00eb artikullit, ju ftoj t\u00eb votoni p\u00ebr temat m\u00eb t\u00eb interesuara p\u00ebr ju.
\n<\/em><\/p>\n

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\"Blloqet<\/p>\n

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Ky \u00ebsht\u00eb artikulli p\u00ebrfundimtar i ciklit p\u00ebr aplikacione reaktive t\u00eb shp\u00ebrndara n\u00eb Erlang\/Elixir. N\u00eb artikullin e par\u00eb<\/a><\/noindex> mund t\u00eb gjeni bazat teorike t\u00eb arkitektur\u00ebs reaktive. Artikulli i dyt\u00eb<\/a><\/noindex> ilustron modelet dhe mekanizmat kryesor\u00eb t\u00eb nd\u00ebrtimit t\u00eb sistemeve t\u00eb tilla.<\/p>\n

<\/p>\n

Sot do t\u00eb diskutojm\u00eb p\u00ebr zhvillimin e kodit baz\u00eb dhe projekteve n\u00eb p\u00ebrgjith\u00ebsi. <\/p>\n

<\/a><\/noindex><\/p>\n

Organizimi i sh\u00ebrbimeve<\/h2>\n

<\/p>\n

N\u00eb jet\u00ebn reale, gjat\u00eb zhvillimit t\u00eb nj\u00eb sh\u00ebrbimi, shpesh duhet t\u00eb bashkohen disa modele nd\u00ebrveprimi n\u00eb nj\u00eb kontrollues. P\u00ebr shembull, sh\u00ebrbimi users, i cili zgjidh problemet e menaxhimit t\u00eb profileve t\u00eb p\u00ebrdoruesve t\u00eb projektit, duhet t\u00eb p\u00ebrgjigjet n\u00eb k\u00ebrkesat req-resp dhe t\u00eb raportoj\u00eb p\u00ebr p\u00ebrdit\u00ebsimet e profileve p\u00ebrmes pub-sub. Ky rast \u00ebsht\u00eb mjaft i thjesht\u00eb: p\u00ebr messaging q\u00ebndron nj\u00eb kontrollues, i cili implementon logjik\u00ebn e sh\u00ebrbimit dhe publikon p\u00ebrdit\u00ebsime.<\/p>\n

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Situata komplikohet kur na nevojitet t\u00eb implementojm\u00eb nj\u00eb sh\u00ebrbim t\u00eb shp\u00ebrndar\u00eb rezistent ndaj d\u00ebshtimeve. Le t\u00eb imagjinojm\u00eb se k\u00ebrkesat p\u00ebr users jan\u00eb ndryshuar: <\/p>\n

<\/p>\n

    \n
  1. tani sh\u00ebrbimi duhet t\u00eb p\u00ebrpunoj\u00eb k\u00ebrkesat n\u00eb 5 nyje t\u00eb klasterit, <\/li>\n
  2. t\u00eb ket\u00eb mund\u00ebsin\u00eb e ekzekutimit t\u00eb detyrave t\u00eb prapame, <\/li>\n
  3. si dhe t\u00eb din\u00eb t\u00eb menaxhojn\u00eb dinamikisht listat e abonimit p\u00ebr p\u00ebrdit\u00ebsimet e profileve.<\/li>\n<\/ol>\n

    <\/p>\n

    Sh\u00ebnim:<\/em> Ne nuk e shqyrtojm\u00eb \u00e7\u00ebshtjen e ruajtjes konsistente dhe replikimit t\u00eb t\u00eb dh\u00ebnave. Supozojm\u00eb se k\u00ebto \u00e7\u00ebshtje jan\u00eb zgjidhur m\u00eb par\u00eb dhe n\u00eb sistem tashm\u00eb ekziston nj\u00eb shtres\u00eb e besueshme dhe e shkall\u00ebzueshme e ruajtjes, dhe p\u00ebrpunuesit kan\u00eb mekanizma nd\u00ebrveprimi me t\u00eb.<\/p>\n

    <\/p>\n

    P\u00ebrshkrimi formal i sh\u00ebrbimit users \u00ebsht\u00eb komplikuar. Nga k\u00ebndv\u00ebshtrimi i programuesit, fal\u00eb p\u00ebrdorimit t\u00eb messaging-ut, ndryshimet jan\u00eb minime. P\u00ebr t\u00eb p\u00ebrmbushur k\u00ebrkes\u00ebn e par\u00eb, na nevojitet t\u00eb konfigurojm\u00eb balancimin n\u00eb pik\u00ebn e ndarjes req-resp. <\/p>\n

    <\/p>\n

    K\u00ebrkesa p\u00ebr p\u00ebrcaktimin e detyrave n\u00eb sfond ndodh shpesh. N\u00eb p\u00ebrdoruesit kjo mund t\u00eb jet\u00eb verifikimi i dokumenteve t\u00eb p\u00ebrdoruesve, p\u00ebrpunimi i multimediave t\u00eb ngarkuara, ose sinkronizimi i t\u00eb dh\u00ebnave me rrjetet sociale. K\u00ebto detyra duhet ndar\u00eb ndonj\u00ebfar\u00eb m\u00ebnyre brenda klasterit dhe t\u00eb kontrollohet progresi i ekzekutimit. Prandaj kemi dy mund\u00ebsi zgjidhjeje: ose t\u00eb p\u00ebrdorim modelin e shp\u00ebrndarjes s\u00eb detyrave nga Artikulli i kaluar, ose, n\u00ebse ai nuk \u00ebsht\u00eb i p\u00ebrshtatsh\u00ebm, t\u00eb shkruajm\u00eb nj\u00eb planifikues t\u00eb personalizuar t\u00eb detyrave q\u00eb do t\u00eb menaxhoj\u00eb pool-in e p\u00ebrpunuesve ashtu si\u00e7 na nevojitet. <\/p>\n

    <\/p>\n

    Pika 3 k\u00ebrkon zgjerimin e modelit pub-sub. Dhe p\u00ebr ta realizuar, pas krijimit t\u00eb pik\u00ebs s\u00eb k\u00ebmbimit pub-sub, na nevojitet t\u00eb aktivizojm\u00eb nj\u00eb kontrollues t\u00eb k\u00ebsaj pike brenda sh\u00ebrbimit ton\u00eb. K\u00ebshtu, duket sikur e heqim logjik\u00ebn e p\u00ebrpunimit t\u00eb abonimeve dhe shk\u00ebputjeve nga sipari messaging n\u00eb implementimin e p\u00ebrdoruesve.<\/p>\n

    <\/p>\n

    Si rezultat, dekompozimi i detyr\u00ebs tregoi se p\u00ebr t\u00eb p\u00ebrmbushur k\u00ebrkesat, na nevojitet t\u00eb aktivizojm\u00eb n\u00eb nyje t\u00eb ndryshme 5 kopje t\u00eb sh\u00ebrbimit dhe t\u00eb krijojm\u00eb nj\u00eb entitet shtes\u00eb \u2013 kontrolluesin pub-sub, p\u00ebrgjegj\u00ebs p\u00ebr abonimin.
    \nP\u00ebr t\u00eb aktivizuar 5 p\u00ebrpunuesit, nuk k\u00ebrkohet t\u00eb ndryshojm\u00eb kodin e sh\u00ebrbimit. Veprimi i vet\u00ebm shtes\u00eb \u00ebsht\u00eb konfigurimi i rregullave t\u00eb balancimit n\u00eb pik\u00ebn e k\u00ebmbimit, p\u00ebr t\u00eb cilin do t\u00eb flasim pak m\u00eb von\u00eb.
    \nGjithashtu ka nj\u00eb kompleksitet shtes\u00eb: kontrolluesi pub-sub dhe planifikuesi i personalizuar i detyrave duhet t\u00eb punojn\u00eb n\u00eb nj\u00eb kopje t\u00eb vetme. Po ashtu, sh\u00ebrbimi messaging, si nj\u00eb themelor, duhet t\u00eb ofroj\u00eb nj\u00eb mekaniz\u00ebm p\u00ebr zgjedhjen e liderit.<\/p>\n

    <\/p>\n

    Zgjedhja e liderit<\/h3>\n

    <\/p>\n

    N\u00eb sistemet e shp\u00ebrndara, zgjedhja e liderit \u00ebsht\u00eb nj\u00eb procedur\u00eb p\u00ebr em\u00ebrimin e nj\u00eb procesi t\u00eb vet\u00ebm, p\u00ebrgjegj\u00ebs p\u00ebr planifikimin e p\u00ebrpunimit t\u00eb shp\u00ebrndar\u00eb t\u00eb ndonj\u00eb ngarkese. <\/p>\n

    <\/p>\n

    N\u00eb sistemet q\u00eb nuk e preferojn\u00eb centralizimin, p\u00ebrdoren algoritme universale dhe algoritme t\u00eb bazuara n\u00eb konsensus, si\u00e7 jan\u00eb paxos ose raft.
    \nDhe meq\u00eb messaging \u00ebsht\u00eb nj\u00eb broker dhe element qendror, ai di p\u00ebr t\u00eb gjith\u00eb kontrolluesit e sh\u00ebrbimit \u2013 kandidat\u00ebt p\u00ebr lider\u00eb. Messaging mund t\u00eb em\u00ebroj\u00eb nj\u00eb lider pa organizuar votim.<\/p>\n

    <\/p>\n

    T\u00eb gjitha sh\u00ebrbimet pas fillimit dhe lidhjes me pik\u00ebn e k\u00ebmbimit marrin nj\u00eb mesazh sistemik #'$leader'{exchange = ?EXCHANGE, pid = LeaderPid, servers = Servers}<\/code>. N\u00eb rast se LeaderPid<\/code> p\u00ebrputhet me pid<\/code> e procesit aktual, ai em\u00ebrohet lider, dhe lista Servers<\/code> p\u00ebrfshin t\u00eb gjitha nyjet dhe parametrat e tyre.
    \nN\u00eb momentin e shfaqjes s\u00eb nj\u00eb nyjeje t\u00eb re dhe \u00e7aktivizimit t\u00eb nj\u00eb nyjeje funksionale t\u00eb klasterit, t\u00eb gjitha kontrolluesit e sh\u00ebrbimit marrin #'$slave_up'{exchange = ?EXCHANGE, pid = SlavePid, options = SlaveOpts}<\/code> \u0438 #'$slave_down'{exchange = ?EXCHANGE, pid = SlavePid, options = SlaveOpts}<\/code> p\u00ebrkat\u00ebsisht.<\/p>\n

    <\/p>\n

    K\u00ebshtu, t\u00eb gjitha komponent\u00ebt e din\u00eb p\u00ebr t\u00eb gjitha ndryshimet, dhe n\u00eb klaster n\u00eb \u00e7do moment \u00ebsht\u00eb garantuar nj\u00eb lider.<\/p>\n

    <\/p>\n

    M\u00ebnyra t\u00eb nd\u00ebrmjetme<\/h2>\n

    <\/p>\n

    P\u00ebr realizimin e proceseve t\u00eb ndar\u00eb t\u00eb p\u00ebrpunimit t\u00eb informacionit, si dhe n\u00eb detyrat e optimizimit t\u00eb arkitektur\u00ebs ekzistuese, \u00ebsht\u00eb e leht\u00eb t\u00eb aplikohen nd\u00ebrmjet\u00ebs.
    \nP\u00ebr t\u00eb mos ndryshuar kodin e sh\u00ebrbimeve dhe p\u00ebr t\u00eb zgjidhur, p\u00ebr shembull, problemet e p\u00ebrpunimit shtes\u00eb, ruterizimit ose regjistrimit t\u00eb mesazheve, para sh\u00ebrbimit mund t\u00eb aktivizohet nj\u00eb p\u00ebrpunues proxy, i cili do t\u00eb b\u00ebj\u00eb t\u00eb gjith\u00eb pun\u00ebn shtes\u00eb.<\/p>\n

    <\/p>\n

    Nj\u00eb shembull klasik i optimizimit pub-sub \u00ebsht\u00eb nj\u00eb aplikacion i shp\u00ebrndar\u00eb me b\u00ebrtham\u00ebn e biznesit, q\u00eb gjeneron ngjarje t\u00eb p\u00ebrdit\u00ebsimeve, p\u00ebr shembull ndryshimin e \u00e7mimit n\u00eb treg, dhe shtresa e aksesit \u2014 N server\u00eb q\u00eb ofrojn\u00eb API websocket p\u00ebr klient\u00ebt web.
    \nN\u00ebse e zgjidhim \u2018ashtu si\u00e7 \u00ebsht\u00eb\u2019, sh\u00ebrbimi p\u00ebr klientin duket k\u00ebshtu:<\/p>\n

    <\/p>\n