Implement other_workers() and other_procs()

These are handy if you want to iterate over every worker/process except the
current one.

Author: JamesWrigley

docs/src/_changelog.md

@@ -16,6 +16,8 @@ This documents notable changes in DistributedNext.jl. The format is based on
 - A watcher mechanism has been added to detect when both the Distributed stdlib
   and DistributedNext may be active and adding workers. This should help prevent
   incompatibilities from both libraries being used simultaneously ([#10]).
+- [`other_workers()`](@ref) and [`other_procs()`](@ref) were implemented and
+  exported ([#18]).
 
 ## [v1.0.0] - 2024-12-02
 

docs/src/index.md

@@ -7,7 +7,9 @@ DistributedNext.nprocs
 DistributedNext.nworkers
 DistributedNext.procs()
 DistributedNext.procs(::Integer)
+DistributedNext.other_procs()
 DistributedNext.workers
+DistributedNext.other_workers
 DistributedNext.rmprocs
 DistributedNext.interrupt
 DistributedNext.myid

src/DistributedNext.jl

@@ -48,13 +48,15 @@ export
     nworkers,
     pmap,
     procs,
+    other_procs,
     remote,
     remotecall,
     remotecall_fetch,
     remotecall_wait,
     remote_do,
     rmprocs,
     workers,
+    other_workers,
     WorkerPool,
     RemoteChannel,
     Future,

src/cluster.jl

@@ -937,6 +937,8 @@ end
 
 Return a list of all process identifiers, including pid 1 (which is not included by [`workers()`](@ref)).
 
+See also [`other_procs()`](@ref).
+
 # Examples
 ```julia-repl
 \$ julia -p 2
@@ -957,6 +959,14 @@ function procs()
     end
 end
 
+"""
+    other_procs([pid::Integer])
+
+Identical to [`procs()`](@ref) and [`procs(::Integer)`](@ref), except that the
+current worker is filtered out.
+"""
+other_procs() = filter(!=(myid()), procs())
+
 function id_in_procs(id)  # faster version of `id in procs()`
     if myid() == 1 || (PGRP.topology === :all_to_all  && !isclusterlazy())
         for x in PGRP.workers
@@ -979,6 +989,8 @@ end
 
 Return a list of all process identifiers on the same physical node.
 Specifically all workers bound to the same ip-address as `pid` are returned.
+
+See also [`other_procs()`](@ref).
 """
 function procs(pid::Integer)
     if myid() == 1
@@ -994,11 +1006,15 @@ function procs(pid::Integer)
     end
 end
 
+other_procs(pid::Integer) = filter(!=(myid()), procs(pid))
+
 """
     workers()
 
 Return a list of all worker process identifiers.
 
+See also [`other_workers()`](@ref).
+
 # Examples
 ```julia-repl
 \$ julia -p 2
@@ -1018,6 +1034,13 @@ function workers()
     end
 end
 
+"""
+    other_workers()
+
+Identical to [`workers()`](@ref) except that the current worker is filtered out.
+"""
+other_workers() = filter(!=(myid()), workers())
+
 function cluster_mgmt_from_master_check()
     if myid() != 1
         throw(ErrorException("Only process 1 can add and remove workers"))

test/distributed_exec.jl

@@ -30,8 +30,15 @@ end
 end
 
 @testset "Distributed loading of packages" begin
-    addprocs_with_testenv(4)
+    @test isempty(other_workers())
+    @test isempty(other_procs())
+
+    pids = addprocs_with_testenv(4)
+
     @test nprocs() == 5
+    @test other_workers() == workers()
+    @test other_procs() == pids
+    @test other_procs(1) == pids
 
     global id_me = myid()
     global id_other = filter(x -> x != id_me, procs())[rand(1:(nprocs()-1))]