Add RemoteLogger

Project.toml

@@ -3,6 +3,7 @@ uuid = "8ba89e20-285c-5b6f-9357-94700520ee1b"
 version = "1.11.0"
 
 [deps]
+Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Serialization = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
 Sockets = "6462fe0b-24de-5631-8697-dd941f90decc"

README.md

@@ -38,6 +38,7 @@ For controlling other processes via RPC:
 For communicating between processes in the style of a channel or stream:
 
 - `RemoteChannel` - a `Channel`-like object that can be `put!` to or `take!` from any process
+- `RemoteLogger`  - an `AbstractLogger` forwarding logs to a given worker 
 
 For controlling multiple processes at once:
 

src/Distributed.jl

@@ -21,6 +21,7 @@ using Base.Threads: Event
 using Serialization, Sockets
 import Serialization: serialize, deserialize
 import Sockets: connect, wait_connected
+import Logging
 
 # NOTE: clusterserialize.jl imports additional symbols from Serialization for use
 
@@ -60,6 +61,7 @@ export
     WorkerConfig,
     RemoteException,
     ProcessExitedException,
+    RemoteLogger,
 
     process_messages,
     remoteref_id,
@@ -107,6 +109,7 @@ include("messages.jl")
 include("process_messages.jl")  # process incoming messages
 include("remotecall.jl")  # the remotecall* api
 include("macros.jl")      # @spawn and friends
+include("logger.jl")
 include("workerpool.jl")
 include("pmap.jl")
 include("managers.jl")    # LocalManager and SSHManager

src/logger.jl

@@ -0,0 +1,27 @@
+"""
+    RemoteLogger(pid=1, min_level=Info)
+
+Logger that forward all logging to worker `pid` via `remote_do` along with
+adding the current worker `id` as a `pid` kwarg.
+"""
+struct RemoteLogger <: Logging.AbstractLogger
+    pid::Int
+    min_level::Logging.LogLevel
+end
+function RemoteLogger(pid=1)
+    RemoteLogger(pid, Logging.Info)
+end
+
+Logging.min_enabled_level(logger::RemoteLogger) = logger.min_level
+Logging.shouldlog(logger::RemoteLogger, level, _module, group, id) = true
+
+# TODO: probably should live in base/logging.jl?
+function logmsg(level::Logging.LogLevel, message, _module, _group, _id, _file, _line; kwargs...)
+    Logging.@logmsg level message _module=_module _group=_group _id=_id _file=_file _line=_line kwargs...
+end
+
+function Logging.handle_message(logger::RemoteLogger, level::Logging.LogLevel, message, _module, _group, _id,
+    _file, _line; kwargs...)
+    @nospecialize
+    remote_do(logmsg, logger.pid, level, message, _module, _group, _id, _file, _line; pid=myid(), kwargs...)
+end

test/distributed_exec.jl

@@ -1,6 +1,6 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
-using Test, Distributed, Random, Serialization, Sockets
+using Test, Distributed, Random, Serialization, Sockets, Logging
 import Distributed: launch, manage
 
 sharedir = normpath(joinpath(Sys.BINDIR, "..", "share"))
@@ -1927,6 +1927,21 @@ begin
     end
 end
 
+# test logging
+w = only(addprocs(1))
+@everywhere using Logging
+@test_logs (:info, "from pid $w") begin
+    prev_logger = global_logger(current_logger())
+    try
+        wait(@spawnat w with_logger(RemoteLogger(1)) do
+                @info("from pid $(myid())")
+            end)
+    finally
+        global_logger(prev_logger)
+    end
+end
+wait(rmprocs([w]))
+
 # Run topology tests last after removing all workers, since a given
 # cluster at any time only supports a single topology.
 nprocs() > 1 && rmprocs(workers())