Make ElasticManager more convenient

Project.toml

@@ -5,6 +5,7 @@ version = "0.4.0"
 [deps]
 Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
 Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
+Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 Sockets = "6462fe0b-24de-5631-8697-dd941f90decc"
 
 [compat]

README.md

@@ -19,7 +19,7 @@ You can also write your own custom cluster manager; see the instructions in the
 
 ### Slurm: a simple example
 
-```jl
+```julia
 using ClusterManagers
 
 # Arguments to the Slurm srun(1) command can be given as keyword
@@ -52,7 +52,7 @@ end
 
 ### SGE - a simple interactive example
 
-```jl
+```julia
 julia> using ClusterManagers
 
 julia> ClusterManagers.addprocs_sge(5)
@@ -79,7 +79,7 @@ julia>  From worker 2:  compute-6
 
 Some clusters require the user to specify a list of required resources. For example, it may be necessary to specify how much memory will be needed by the job - see this [issue](https://github.com/JuliaLang/julia/issues/10390).
 
-```jl
+```julia
 julia> using ClusterManagers
 
 julia> addprocs_sge(5,res_list="h_vmem=4G,tmem=4G")
@@ -136,36 +136,27 @@ The `ElasticManager` is useful in scenarios where we want to dynamically add wor
 It achieves this by listening on a known port on the master. The launched workers connect to this
 port and publish their own host/port information for other workers to connect to.
 
-##### Usage
-
 On the master, you need to instantiate an instance of `ElasticManager`. The constructors defined are:
-```jl
-ElasticManager(;addr=IPv4("127.0.0.1"), port=9009, cookie=nothing, topology=:all_to_all)
+
+```julia
+ElasticManager(;addr=IPv4("127.0.0.1"), port=9009, cookie=nothing, topology=:all_to_all, printing_kwargs=())
 ElasticManager(port) = ElasticManager(;port=port)
 ElasticManager(addr, port) = ElasticManager(;addr=addr, port=port)
 ElasticManager(addr, port, cookie) = ElasticManager(;addr=addr, port=port, cookie=cookie)
 ```
 
-On the worker, you need to call `ClusterManagers.elastic_worker` with the addr/port that the master
-is listening on and the same cookie. `elastic_worker` is defined as:
-```
-ClusterManagers.elastic_worker(cookie, addr="127.0.0.1", port=9009; stdout_to_master=true)
-```
-
-For example, on the master:
+On Linux and Mac, you can set `addr=:auto` to automatically use the host's private IP address on the local network, which will allow other workers on this network to connect. You can also use `port=0` to let the OS choose a random free port for you (some systems may not support this). Once created, printing the `ElasticManager` object prints the command which you can run on workers to connect them to the master, e.g.:
 
-```jl
-using ClusterManagers
-em=ElasticManager(cookie="foobar")
+```julia
+julia> em = ElasticManager(addr=:auto, port=0)
+ElasticManager:
+  Active workers : []
+  Number of workers to be added  : 0
+  Terminated workers : []
+  Worker connect command : 
+    /home/user/bin/julia --project=/home/user/myproject/Project.toml -e 'using ClusterManagers; ClusterManagers.elastic_worker("4cOSyaYpgSl6BC0C","127.0.1.1",36275)'
 ```
 
-and launch each worker locally as
-`echo "using ClusterManagers; ClusterManagers.elastic_worker(\"foobar\")" | julia  &`
-
-or if you want a REPL on the worker, you can start a julia process normally and manually enter
-```jl
-using ClusterManagers
-@schedule ClusterManagers.elastic_worker("foobar", "addr_of_master", port_of_master; stdout_to_master=false)
-```
+By default, the printed command uses the absolute path to the current Julia executable and activates the same project as the current session. You can change either of these defaults by passing `printing_kwargs=(absolute_exename=false, same_project=false))` to the first form of the `ElasticManager` constructor. 
 
-The above will yield back the REPL prompt and also display any printed output locally.
+Once workers are connected, you can print the `em` object again to see them added to the list of active workers. 

src/ClusterManagers.jl

@@ -2,6 +2,7 @@ module ClusterManagers
 
 using Distributed
 using Sockets
+using Pkg
 
 export launch, manage, kill, init_worker, connect
 import Distributed: launch, manage, kill, init_worker, connect

src/elastic.jl

@@ -12,14 +12,19 @@ struct ElasticManager <: ClusterManager
     terminated::Set{Int}             # terminated worker ids
     topology::Symbol
     sockname
+    printing_kwargs
 
-    function ElasticManager(;addr=IPv4("127.0.0.1"), port=9009, cookie=nothing, topology=:all_to_all)
+    function ElasticManager(;addr=IPv4("127.0.0.1"), port=9009, cookie=nothing, topology=:all_to_all, printing_kwargs=())
         Distributed.init_multi()
         cookie !== nothing && cluster_cookie(cookie)
 
+        if addr == :auto
+            addr = get_private_ip()
+        end
+
         l_sock = listen(addr, port)
 
-        lman = new(Dict{Int, WorkerConfig}(), Channel{TCPSocket}(typemax(Int)), Set{Int}(), topology, getsockname(l_sock))
+        lman = new(Dict{Int, WorkerConfig}(), Channel{TCPSocket}(typemax(Int)), Set{Int}(), topology, getsockname(l_sock), printing_kwargs)
 
         @async begin
             while true
@@ -113,6 +118,9 @@ function Base.show(io::IO, mgr::ElasticManager)
     seek(iob, position(iob)-1)
     println(iob, "]")
 
+    println(iob, "  Worker connect command : ")
+    print(iob, "    ", get_connect_cmd(mgr; mgr.printing_kwargs...))
+
     print(io, String(take!(iob)))
 end
 
@@ -125,3 +133,38 @@ function elastic_worker(cookie, addr="127.0.0.1", port=9009; stdout_to_master=tr
     stdout_to_master && redirect_stdout(c)
     start_worker(c, cookie)
 end
+
+
+function get_private_ip()
+    if Sys.islinux()
+        cmd = `hostname --ip-address`
+    elseif Sys.isapple()
+        cmd = `ipconfig getifaddr en0`
+    else
+        error("`addr=:auto` is only supported on Linux and Mac")
+    end
+    try
+        return IPv4(first(split(strip(read(cmd, String)))))
+    catch err
+        error("""Failed to automatically get host's IP address (output below). Please specify `addr=` explicitly.
+        \$ $(repr(cmd))
+        $err
+        """)
+    end
+end
+
+function get_connect_cmd(em::ElasticManager; absolute_exename=true, same_project=true)
+
+    ip = string(em.sockname[1])
+    port = convert(Int,em.sockname[2])
+    cookie = cluster_cookie()
+    exename = absolute_exename ? joinpath(Sys.BINDIR, Base.julia_exename()) : "julia"
+    project = same_project ? ("--project=$(Pkg.API.Context().env.project_file)",) : ()
+
+    join([
+        exename,
+        project...,
+        "-e 'using ClusterManagers; ClusterManagers.elastic_worker(\"$cookie\",\"$ip\",$port)'"
+    ]," ")
+
+end

test/runtests.jl

@@ -1,2 +1,18 @@
-# only package loading for now
+using Test
 using ClusterManagers
+
+TIMEOUT = 10.
+
+@testset "ElasticManager" begin
+
+    em = ElasticManager(addr=:auto, port=0)
+
+    # launch worker
+    run(`sh -c $(ClusterManagers.get_connect_cmd(em))`, wait=false)
+
+    # wait at most TIMEOUT seconds for it to connect
+    @test :ok == timedwait(TIMEOUT) do
+        length(em.active) == 1
+    end
+
+end