Description of generic mount flow

generic_mount_flow.plantuml

@startuml

autonumber
hide footbox

participant "wrapper\n(stage 2)" as wrapper
participant "stage 1" as stage_1
participant master
participant "rpc server" as rpc_server

wrapper -> stage_1 ** : spawn
activate stage_1
note over stage_1: prepare config
stage_1 -> wrapper: send config
deactivate stage_1

note over wrapper: create socket pair A
note over wrapper: create socket pair B
wrapper -> master ** : spawn
note over wrapper: close A[0]
activate master
note over master: close A[1]
note over master: close B[0]

wrapper -> rpc_server ** : spawn
note over rpc_server: close B[1]
note over wrapper: close B[0]
note over wrapper: close B[1]
activate rpc_server

master -> rpc_server: request open over B[1]
rpc_server -> master: send fd over B[0]
note over master: mount passing\nfd as option
master -> wrapper: send fd over A[0]

note over wrapper: enter stage 2
note over wrapper: start pre-process\nuse fd
note over wrapper: start process


@enduml

generic_mount_flow.svg

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stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="128" x="14" y="200.2231">create socket pair A</text><path d="M8,222.2891 L8,247.2891 L157,247.2891 L157,232.2891 L147,222.2891 L8,222.2891 " fill="#FBFB77" filter="url(#f17rnqlh25nd07)" style="stroke: #A80036; stroke-width: 1.0;"/><path d="M147,222.2891 L147,232.2891 L157,232.2891 L147,222.2891 " fill="#FBFB77" style="stroke: #A80036; stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="128" x="14" y="239.356">create socket pair B</text><polygon fill="#A80036" points="232,273.5547,242,277.5547,232,281.5547,236,277.5547" style="stroke: #A80036; stroke-width: 1.0;"/><line style="stroke: #A80036; stroke-width: 1.0;" x1="84" x2="238" y1="277.5547" y2="277.5547"/><text fill="#000000" font-family="sans-serif" font-size="13" font-weight="bold" lengthAdjust="spacingAndGlyphs" textLength="9" x="91" y="272.4888">3</text><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="40" x="104" y="272.4888">spawn</text><rect fill="#FEFECE" filter="url(#f17rnqlh25nd07)" height="30.2969" style="stroke: #A80036; stroke-width: 1.5;" width="62" x="244" y="256.4219"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacingAndGlyphs" textLength="48" x="251" y="276.417">master</text><path d="M39,306.7188 L39,331.7188 L124,331.7188 L124,316.7188 L114,306.7188 L39,306.7188 " fill="#FBFB77" filter="url(#f17rnqlh25nd07)" style="stroke: #A80036; stroke-width: 1.0;"/><path d="M114,306.7188 L114,316.7188 L124,316.7188 L114,306.7188 " fill="#FBFB77" style="stroke: #A80036; stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="64" x="45" y="323.7856">close A[0]</text><path d="M232,345.8516 L232,370.8516 L317,370.8516 L317,355.8516 L307,345.8516 L232,345.8516 " fill="#FBFB77" filter="url(#f17rnqlh25nd07)" style="stroke: #A80036; stroke-width: 1.0;"/><path d="M307,345.8516 L307,355.8516 L317,355.8516 L307,345.8516 " fill="#FBFB77" style="stroke: #A80036; stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="64" x="238" y="362.9185">close A[1]</text><path d="M232,384.9844 L232,409.9844 L317,409.9844 L317,394.9844 L307,384.9844 L232,384.9844 " fill="#FBFB77" filter="url(#f17rnqlh25nd07)" style="stroke: #A80036; stroke-width: 1.0;"/><path d="M307,384.9844 L307,394.9844 L317,394.9844 L307,384.9844 " fill="#FBFB77" style="stroke: #A80036; stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="64" x="238" y="402.0513">close B[0]</text><polygon fill="#A80036" points="416.5,436.25,426.5,440.25,416.5,444.25,420.5,440.25" style="stroke: #A80036; stroke-width: 1.0;"/><line style="stroke: #A80036; stroke-width: 1.0;" x1="84" x2="422.5" y1="440.25" y2="440.25"/><text fill="#000000" font-family="sans-serif" font-size="13" font-weight="bold" lengthAdjust="spacingAndGlyphs" textLength="9" x="91" y="435.1841">4</text><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="40" x="104" y="435.1841">spawn</text><rect fill="#FEFECE" filter="url(#f17rnqlh25nd07)" height="30.2969" style="stroke: #A80036; stroke-width: 1.5;" width="83" x="428.5" y="419.1172"/><text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacingAndGlyphs" textLength="69" x="435.5" y="439.1123">rpc server</text><path d="M427,469.4141 L427,494.4141 L512,494.4141 L512,479.4141 L502,469.4141 L427,469.4141 " fill="#FBFB77" filter="url(#f17rnqlh25nd07)" style="stroke: #A80036; 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stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="64" x="45" y="564.7466">close B[1]</text><polygon fill="#A80036" points="455,598.9453,465,602.9453,455,606.9453,459,602.9453" style="stroke: #A80036; stroke-width: 1.0;"/><line style="stroke: #A80036; stroke-width: 1.0;" x1="282" x2="461" y1="602.9453" y2="602.9453"/><text fill="#000000" font-family="sans-serif" font-size="13" font-weight="bold" lengthAdjust="spacingAndGlyphs" textLength="9" x="289" y="597.8794">5</text><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="148" x="302" y="597.8794">request open over B[1]</text><polygon fill="#A80036" points="293,628.0781,283,632.0781,293,636.0781,289,632.0781" style="stroke: #A80036; stroke-width: 1.0;"/><line style="stroke: #A80036; stroke-width: 1.0;" x1="287" x2="466" y1="632.0781" y2="632.0781"/><text fill="#000000" font-family="sans-serif" font-size="13" font-weight="bold" lengthAdjust="spacingAndGlyphs" textLength="9" x="299" y="627.0122">6</text><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="110" x="312" y="627.0122">send fd over B[0]</text><path d="M217,645.0781 L217,685.0781 L333,685.0781 L333,655.0781 L323,645.0781 L217,645.0781 " fill="#FBFB77" filter="url(#f17rnqlh25nd07)" style="stroke: #A80036; stroke-width: 1.0;"/><path d="M323,645.0781 L323,655.0781 L333,655.0781 L323,645.0781 " fill="#FBFB77" style="stroke: #A80036; stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="95" x="223" y="662.145">mount passing</text><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="75" x="223" y="677.2778">fd as option</text><polygon fill="#A80036" points="95,711.4766,85,715.4766,95,719.4766,91,715.4766" style="stroke: #A80036; stroke-width: 1.0;"/><line style="stroke: #A80036; stroke-width: 1.0;" x1="89" x2="271" y1="715.4766" y2="715.4766"/><text fill="#000000" font-family="sans-serif" font-size="13" font-weight="bold" lengthAdjust="spacingAndGlyphs" textLength="9" x="101" y="710.4106">7</text><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="110" x="114" y="710.4106">send fd over A[0]</text><path d="M28,728.4766 L28,753.4766 L135,753.4766 L135,738.4766 L125,728.4766 L28,728.4766 " fill="#FBFB77" filter="url(#f17rnqlh25nd07)" style="stroke: #A80036; stroke-width: 1.0;"/><path d="M125,728.4766 L125,738.4766 L135,738.4766 L125,728.4766 " fill="#FBFB77" style="stroke: #A80036; stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="86" x="34" y="745.5435">enter stage 2</text><path d="M16,767.6094 L16,807.6094 L147,807.6094 L147,777.6094 L137,767.6094 L16,767.6094 " fill="#FBFB77" filter="url(#f17rnqlh25nd07)" style="stroke: #A80036; stroke-width: 1.0;"/><path d="M137,767.6094 L137,777.6094 L147,777.6094 L137,767.6094 " fill="#FBFB77" style="stroke: #A80036; stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="110" x="22" y="784.6763">start pre-process</text><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="39" x="22" y="799.8091">use fd</text><path d="M29,821.875 L29,846.875 L134,846.875 L134,831.875 L124,821.875 L29,821.875 " fill="#FBFB77" filter="url(#f17rnqlh25nd07)" style="stroke: #A80036; stroke-width: 1.0;"/><path d="M124,821.875 L124,831.875 L134,831.875 L124,821.875 " fill="#FBFB77" style="stroke: #A80036; stroke-width: 1.0;"/><text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="84" x="35" y="838.9419">start process</text><!--
@startuml
autonumber
hide footbox

participant "wrapper\n(stage 2)" as wrapper
participant "stage 1" as stage_1
participant master
participant "rpc server" as rpc_server

wrapper -> stage_1 ** : spawn
activate stage_1
note over stage_1: prepare config
stage_1 -> wrapper: send config
deactivate stage_1

note over wrapper: create socket pair A
note over wrapper: create socket pair B
wrapper -> master ** : spawn
note over wrapper: close A[0]
activate master
note over master: close A[1]
note over master: close B[0]

wrapper -> rpc_server ** : spawn
note over rpc_server: close B[1]
note over wrapper: close B[0]
note over wrapper: close B[1]
activate rpc_server

master -> rpc_server: request open over B[1]
rpc_server -> master: send fd over B[0]
note over master: mount passing\nfd as option
master -> wrapper: send fd over A[0]

note over wrapper: enter stage 2
note over wrapper: start pre-process\nuse fd
note over wrapper: start process
@enduml

PlantUML version 1.2019.04(Fri Mar 29 15:44:36 UTC 2019)
(GPL source distribution)
Java Runtime: OpenJDK Runtime Environment
JVM: OpenJDK 64-Bit Server VM
Java Version: 1.8.0_201-heroku-b09
Operating System: Linux
OS Version: 4.4.0-1042-aws
Default Encoding: UTF-8
Language: en
Country: US
--></g></svg>