Masterslave algorithm

masterslave.q

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+//Master slave algorithm
+//Each process initially assumes it's the master process
+//Master process is determined by oldest process start time 
+//Connect to other slave processes and retrieve details to determine which process is master
+
+//run lines
+//q torq.q -load masterslave.q -proctype lb -procname lb1 -p 6100 -debug -parentproctype wdb
+//q torq.q -load masterslave.q -proctype lb -procname lb2 -p 6101 -debug -parentproctype wdb
+
+
+// the list of processes to connect to
+.servers.CONNECTIONS:`lb
+
+// custom function, this is invoked when a new outbound connection is created
+// to be customised to invoke negotiation of processes
+.servers.connectcustom:{.lg.o[`connect;"found new connection"]; show x}
+
+// create connections
+.servers.startup[]
+
+\d .masterslave
+
+//table scehma of connected lb processes with ismaster status
+statustable:([handle:`int$()] procname:`symbol$();starttimeUTC:`timestamp$();ismaster:`boolean$())
+
+//store own process start timestamp
+start:.z.p
+
+//set details dict with own details
+details:{`procname`starttimeUTC`ismaster!(.proc.procname;.masterslave.start;1b)} 
+
+//get details of procname provided
+getdetails:{[processname] (first exec w from .servers.SERVERS where procname like processname) ".masterslave.details[]"}
+
+//update .masterslave.statustable with other proc details and update ismaster col to determine which process is master 
+addmember:{[processname]
+    update ismaster:0b from (`.masterslave.statustable upsert .masterslave.getdetails[processname],(enlist `handle)!(enlist first exec w from .servers.SERVERS  where procname like processname)) where starttimeUTC<>min starttimeUTC}
+
+//is the process itself the master
+ammaster:{exec ismaster from .masterslave.statustable where handle=0}
+
+//find which process is the master
+findmaster:{first exec handle from .masterslave.statustable where ismaster=1b}
+
+//wrapper func for finding master
+checkifmaster:{
+    .servers.startup[];
+    .masterslave.addmember each string exec procname from .servers.SERVERS where proctype like "lb", not null w
+ }
+
+//add pc override here
+//remove dropped connection from statustable
+//tell other alive processes to renegotiate who the master is 
+
+
+\d .
+
+//populate statutable and find which process is master
+.masterslave.checkifmaster[]
+
+
+//.z.pc call