added logging() for redirection of info/warn/error messages

NEWS.md

@@ -52,6 +52,9 @@ Language changes
   * The built-in `NTuple` type has been removed; `NTuple{N,T}` is now
     implemented internally as `Tuple{Vararg{T,N}}` ([#11242]).
 
+  * `logging` can be used to redirect `info`, `warn`, and `error` messages
+    either universally or on a per-module/function basis ([#16213]).
+
 Command-line option changes
 ---------------------------
 

base/REPL.jl

@@ -95,13 +95,6 @@ function start_repl_backend(repl_channel::Channel, response_channel::Channel)
     backend
 end
 
-function display_error(io::IO, er, bt)
-    Base.with_output_color(:red, io) do io
-        print(io, "ERROR: ")
-        Base.showerror(io, er, bt)
-    end
-end
-
 immutable REPLDisplay{R<:AbstractREPL} <: Display
     repl::R
 end
@@ -124,8 +117,7 @@ function print_response(errio::IO, val::ANY, bt, show_value::Bool, have_color::B
     while true
         try
             if bt !== nothing
-                display_error(errio, val, bt)
-                println(errio)
+                Base.display_error(errio, val, bt)
                 iserr, lasterr = false, ()
             else
                 if val !== nothing && show_value

base/client.jl

@@ -90,14 +90,17 @@ function repl_cmd(cmd, out)
     nothing
 end
 
-display_error(er) = display_error(er, [])
-function display_error(er, bt)
-    with_output_color(:red, STDERR) do io
+function display_error(io::IO, er, bt)
+    sf = StackTraces.remove_frames!(stacktrace(bt), :error)[1]
+    io, mo, fu = redirect(io, log_error_to, sf)
+    with_output_color(:red, io) do io
         print(io, "ERROR: ")
         showerror(io, er, bt)
         println(io)
     end
 end
+display_error(er, bt) = display_error(STDERR, er, bt)
+display_error(er) = display_error(er, [])
 
 function eval_user_input(ast::ANY, show_value)
     errcount, lasterr, bt = 0, (), nothing

base/docs/helpdb/Base.jl

@@ -3592,13 +3592,6 @@ behavior, including program corruption or segfaults, at any later time.
 """
 unsafe_convert
 
-"""
-    warn(msg)
-
-Display a warning. Argument `msg` is a string describing the warning to be displayed.
-"""
-warn
-
 """
     erfinv(x)
 
@@ -4641,13 +4634,6 @@ multiple of four, this is equivalent to a `copy`.
 """
 rotl90(A, k)
 
-"""
-    info(msg)
-
-Display an informational message. Argument `msg` is a string describing the information to be displayed.
-"""
-info
-
 """
     eigmin(A)
 
@@ -6858,13 +6844,6 @@ Airy function ``\\operatorname{Ai}(x)``.
 """
 airyai
 
-"""
-    error(message::AbstractString)
-
-Raise an `ErrorException` with the given message.
-"""
-error
-
 """
     less(file::AbstractString, [line])
 

base/error.jl

@@ -19,7 +19,15 @@
 ## native julia error handling ##
 
 error(s::AbstractString) = throw(Main.Base.ErrorException(s))
-error(s...) = throw(Main.Base.ErrorException(Main.Base.string(s...)))
+
+"""
+    error(msg...)
+
+Raise an `ErrorException` with the given message.
+
+See also `logging`.
+"""
+error(msg...) = error(Main.Base.string(msg...))
 
 rethrow() = ccall(:jl_rethrow, Bottom, ())
 rethrow(e) = ccall(:jl_rethrow_other, Bottom, (Any,), e)

base/exports.jl

@@ -846,6 +846,7 @@ export
     isxdigit,
     join,
     lcfirst,
+    logging,
     lowercase,
     lpad,
     lstrip,

base/sysimg.jl

@@ -272,6 +272,10 @@ include("REPLCompletions.jl")
 include("REPL.jl")
 include("client.jl")
 
+# Stack frames and traces
+include("stacktraces.jl")
+importall .StackTraces
+
 # misc useful functions & macros
 include("util.jl")
 
@@ -314,10 +318,6 @@ include("libgit2.jl")
 include("pkg.jl")
 const Git = Pkg.Git
 
-# Stack frames and traces
-include("stacktraces.jl")
-importall .StackTraces
-
 # profiler
 include("profile.jl")
 importall .Profile

base/util.jl

@@ -332,18 +332,79 @@ println_with_color(color::Symbol, msg::AbstractString...) =
 
 ## warnings and messages ##
 
-function info(io::IO, msg...; prefix="INFO: ")
-    println_with_color(info_color(), io, prefix, chomp(string(msg...)))
+const have_warned = Set()
+const log_info_to = Dict()
+const log_warn_to = Dict()
+const log_error_to = Dict()
+
+function redirect(io::IO, log_to::Dict, sf::StackTraces.StackFrame)
+    mo = sf.outer_linfo.value.def.module
+    fu = sf.func
+    if !isempty(log_to)
+        if haskey(log_to, (mo,fu))
+            io = log_to[(mo,fu)]
+        elseif haskey(log_to, (mo,nothing))
+            io = log_to[(mo,nothing)]
+        elseif haskey(log_to, (nothing,nothing))
+            io = log_to[(nothing,nothing)]
+        end
+    end
+    io, mo, fu
 end
-info(msg...; prefix="INFO: ") = info(STDERR, msg..., prefix=prefix)
 
-# print a warning only once
+"""
+    logging(io [, m [, f]][; kind=:all])
+    logging([; kind=:all])
+
+Stream output of informational, warning, and/or error messages to `io`,
+overriding what was otherwise specified.  Optionally, divert stream only for
+module `m`, or specifically function `f` within `m`.  `kind` can also be
+`:info`, `:warn`, and `:error`.  See `Base.log_{info,warn,error}_to` for the
+current set of redirections.  Call `logging` with no arguments (or just the `kind`)
+to reset everything.
+"""
+function logging(io::IO, m::Union{Module,Void}=nothing, f::Union{Symbol,Void}=nothing;
+                 kind::Symbol=:all)
+    (kind==:all || kind==:info)  && (log_info_to[(m,f)] = io)
+    (kind==:all || kind==:warn)  && (log_warn_to[(m,f)] = io)
+    (kind==:all || kind==:error) && (log_error_to[(m,f)] = io)
+    nothing
+end
 
-const have_warned = Set()
+function logging(;  kind::Symbol=:all)
+    (kind==:all || kind==:info)  && empty!(log_info_to)
+    (kind==:all || kind==:warn)  && empty!(log_warn_to)
+    (kind==:all || kind==:error) && empty!(log_error_to)
+    nothing
+end
+
+"""
+    info([io, ] msg..., [prefix="INFO: "])
+
+Display an informational message. Argument `msg` is a string describing the information to be displayed.
+
+See also `logging`.
+"""
+function info(io::IO, msg...; prefix="INFO: ")
+    sf = StackTraces.remove_frames!(stacktrace(), :info)[1]
+    io, mo, fu = redirect(io, log_info_to, sf)
+    println_with_color(info_color(), io, prefix, chomp(string(msg...)), " ($mo.$fu)")
+end
+info(msg...; prefix="INFO: ") = info(STDERR, msg..., prefix=prefix)
 
 warn_once(io::IO, msg...) = warn(io, msg..., once=true)
 warn_once(msg...) = warn(STDERR, msg..., once=true)
 
+"""
+    warn([io, ] msg..., [prefix="WARNING: ", once=false, key=nothing, bt=nothing, filename=nothing, lineno::Int=0])
+
+Display a warning. Argument `msg` is a string describing the warning to be
+displayed.  Set `once` to true and specify a `key` to only display `msg` the
+first time `warn` is called.  If `bt` is not nothing a backtrace is displayed.
+If `filename` is not nothing both it and `lineno` are displayed.
+
+See also `logging`.
+"""
 function warn(io::IO, msg...;
               prefix="WARNING: ", once=false, key=nothing, bt=nothing,
               filename=nothing, lineno::Int=0)
@@ -355,7 +416,9 @@ function warn(io::IO, msg...;
         (key in have_warned) && return
         push!(have_warned, key)
     end
-    print_with_color(warn_color(), io, prefix, str)
+    sf = StackTraces.remove_frames!(stacktrace(), :warn)[1]
+    io, mo, fu = redirect(io, log_warn_to, sf)
+    print_with_color(warn_color(), io, prefix, str, " ($mo.$fu)")
     if bt !== nothing
         show_backtrace(io, bt)
     end

doc/stdlib/base.rst

@@ -1028,12 +1028,14 @@ System
 Errors
 ------
 
-.. function:: error(message::AbstractString)
+.. function:: error(msg...)
 
    .. Docstring generated from Julia source
 
    Raise an ``ErrorException`` with the given message.
 
+   See also ``logging``\ .
+
 .. function:: throw(e)
 
    .. Docstring generated from Julia source

doc/stdlib/io-network.rst

@@ -470,17 +470,28 @@ Text I/O
 
    ``color`` may take any of the values ``:normal``\ , ``:bold``\ , ``:black``\ , ``:blue``\ , ``:cyan``\ , ``:green``\ , ``:magenta``\ , ``:red``\ , ``:white``\ , or  ``:yellow``\ .
 
-.. function:: info(msg)
+.. function:: info([io, ] msg..., [prefix="INFO: "])
 
    .. Docstring generated from Julia source
 
    Display an informational message. Argument ``msg`` is a string describing the information to be displayed.
 
-.. function:: warn(msg)
+   See also ``logging``\ .
+
+.. function:: warn([io, ] msg..., [prefix="WARNING: ", once=false, key=nothing, bt=nothing, filename=nothing, lineno::Int=0])
+
+   .. Docstring generated from Julia source
+
+   Display a warning. Argument ``msg`` is a string describing the warning to be displayed.  Set ``once`` to true and specify a ``key`` to only display ``msg`` the first time ``warn`` is called.  If ``bt`` is not nothing a backtrace is displayed. If ``filename`` is not nothing both it and ``lineno`` are displayed.
+
+   See also ``logging``\ .
+
+.. function:: logging(io [, m [, f]][; kind=:all])
+              logging([; kind=:all])
 
    .. Docstring generated from Julia source
 
-   Display a warning. Argument ``msg`` is a string describing the warning to be displayed.
+   Stream output of informational, warning, and/or error messages to ``io``\ , overriding what was otherwise specified.  Optionally, divert stream only for module ``m``\ , or specifically function ``f`` within ``m``\ .  ``kind`` can also be ``:info``\ , ``:warn``\ , and ``:error``\ .  See ``Base.log_{info,warn,error}_to`` for the current set of redirections.  Call ``logging`` with no arguments (or just the ``kind``\ ) to reset everything.
 
 .. function:: @printf([io::IOStream], "%Fmt", args...)