allow unnesting JSON (#17)

* allow unnesting JSON

* bump version

* Apply suggestions from code review

Co-authored-by: Glenn Moynihan <glennmoy@gmail.com>

* Update src/LoggingFormats.jl

* Apply suggestions from code review

---------

Co-authored-by: Glenn Moynihan <glennmoy@gmail.com>

Project.toml

@@ -1,15 +1,13 @@
 name = "LoggingFormats"
 uuid = "98105f81-4425-4516-93fd-1664fb551ab6"
-version = "1.3.0"
+version = "1.4.0"
 
 [deps]
 JSON3 = "0f8b85d8-7281-11e9-16c2-39a750bddbf1"
 Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
-StructTypes = "856f2bd8-1eba-4b0a-8007-ebc267875bd4"
 
 [compat]
 JSON3 = "1"
-StructTypes = "1"
 julia = "1"
 
 [extras]

src/LoggingFormats.jl

@@ -1,6 +1,8 @@
 module LoggingFormats
 
-import Logging, JSON3, StructTypes
+import Logging, JSON3
+
+const STANDARD_KEYS = (:level, :msg, :module, :file, :line, :group, :id)
 
 ###############
 ## Truncated ##
@@ -56,16 +58,6 @@ lvlstr(lvl::Logging.LogLevel) = lvl >= Logging.Error ? "error" :
                                 lvl >= Logging.Info  ? "info"  :
                                                        "debug"
 
-struct JSONLogMessage{T}
-    level::String
-    msg::String
-    _module::Union{String,Nothing}
-    file::Union{String,Nothing}
-    line::Union{Int,Nothing}
-    group::Union{String,Nothing}
-    id::Union{String,Nothing}
-    kwargs::Dict{String,T}
-end
 
 transform(::Type{String}, v) = string(v)
 transform(::Type{Any}, v) = v
@@ -74,39 +66,76 @@ maybe_stringify_exceptions((e, bt)::Tuple{Exception,Any}) = sprint(Base.display_
 maybe_stringify_exceptions(e::Exception) = sprint(showerror, e)
 maybe_stringify_exceptions(v) = v
 
-function JSONLogMessage{T}(args) where {T}
-    JSONLogMessage{T}(
+unclash_key(k) = k in STANDARD_KEYS ? Symbol("_", k) : k
+
+function to_namedtuple(::Type{T}, args; nest_kwargs) where {T}
+    kw = (k => transform(T, maybe_stringify_exceptions(v)) for (k, v) in args.kwargs)
+    if nest_kwargs
+        kw = (:kwargs => Dict{String, T}(string(k) => transform(T, maybe_stringify_exceptions(v)) for (k, v) in args.kwargs),)
+    else
+        kw = (unclash_key(k) => transform(T, maybe_stringify_exceptions(v)) for (k, v) in args.kwargs)
+    end
+    standard_message = NamedTuple{STANDARD_KEYS}((
         lvlstr(args.level),
         args.message isa AbstractString ? args.message : string(args.message),
         args._module === nothing ? nothing : string(args._module),
         args.file,
         args.line,
         args.group === nothing ? nothing : string(args.group),
         args.id === nothing ? nothing : string(args.id),
-        Dict{String,T}(string(k) => transform(T, maybe_stringify_exceptions(v)) for (k, v) in args.kwargs)
-    )
+    ))
+    return merge(standard_message, kw)
 end
-StructTypes.StructType(::Type{<:JSONLogMessage}) = StructTypes.OrderedStruct()
-StructTypes.names(::Type{<:JSONLogMessage}) = ((:_module, :module), )
 
+"""
+    JSON(; recursive=false, nest_kwargs=true)
+
+Creates a `JSON` format logger. If `recursive=true`, any custom arguments will be recursively serialized as JSON; otherwise, the values will be treated as strings. If `nest_kwargs` is true (the default),  all custom keyword arguments will be under the `kwargs` key. Otherwise, they will be inlined into the top-level JSON object. In the latter case, if the key name clashes with one of the standard keys (`$STANDARD_KEYS`), it will be renamed by prefixing it with a `_`.
+
+## Examples
+
+```julia
+julia> using LoggingFormats, LoggingExtras
+
+julia> with_logger(FormatLogger(LoggingFormats.JSON(; recursive=false), stderr)) do
+    @info "hello, world" key=Dict("hello" => true)
+end
+{"level":"info","msg":"hello, world","module":"Main","file":"REPL[3]","line":2,"group":"REPL[3]","id":"Main_ffce16b4","kwargs":{"key":"Dict{String, Bool}(\"hello\" => 1)"}}
+
+julia> with_logger(FormatLogger(LoggingFormats.JSON(; recursive=true), stderr)) do
+           @info "hello, world" key=Dict("hello" => true)
+end
+{"level":"info","msg":"hello, world","module":"Main","file":"REPL[4]","line":2,"group":"REPL[4]","id":"Main_ffce16b5","kwargs":{"key":{"hello":true}}}
+
+julia> with_logger(FormatLogger(LoggingFormats.JSON(; recursive=true, nest_kwargs=false), stderr)) do
+    @info "hello, world" key=Dict("hello" => true)
+end
+{"level":"info","msg":"hello, world","module":"Main","file":"REPL[5]","line":2,"group":"REPL[5]","id":"Main_ffce16b6","key":{"hello":true}}
+```
+"""
 struct JSON <: Function
     recursive::Bool
+    nest_kwargs::Bool
 end
 
-JSON(; recursive=false) = JSON(recursive)
+JSON(; recursive=false, nest_kwargs=true) = JSON(recursive, nest_kwargs)
 
 function (j::JSON)(io, args)
     if j.recursive
-        logmsg = JSONLogMessage{Any}(args)
+        logmsg = to_namedtuple(Any, args; nest_kwargs=j.nest_kwargs)
         try
             JSON3.write(io, logmsg)
         catch e
-            fallback_msg = JSONLogMessage{String}(args)
-            fallback_msg.kwargs["LoggingFormats.FormatError"] = sprint(showerror, e)
+            if j.nest_kwargs
+                fallback_msg = to_namedtuple(String, args; nest_kwargs=true)
+                fallback_msg.kwargs["LoggingFormats.FormatError"] = sprint(showerror, e)
+            else
+                fallback_msg = (; to_namedtuple(String, args; nest_kwargs=false)..., Symbol("LoggingFormats.FormatError") => sprint(showerror, e))
+            end
             JSON3.write(io, fallback_msg)
         end
     else
-        logmsg = JSONLogMessage{String}(args)
+        logmsg = to_namedtuple(String, args; nest_kwargs=j.nest_kwargs)
         JSON3.write(io, logmsg)
     end
     println(io)

test/runtests.jl

@@ -98,60 +98,98 @@ end
     @test json.kwargs.x == "[1, 2, 3]"
     @test json.kwargs.y == "(1, 2)"
 
-    # `recursive=true`
+
+    # nest_kwargs=false
     io = IOBuffer()
-    with_logger(FormatLogger(JSON(; recursive=true), io)) do
+    with_logger(FormatLogger(JSON(; nest_kwargs=false), io)) do
         y = (1, 2)
-        @info "info msg" x = [1, 2, 3] y = Dict("hi" => Dict("hi2" => [1,2]))
+        @info "info msg" x = [1, 2, 3] y
     end
     json = JSON3.read(seekstart(io))
     @test json.level == "info"
     @test json.msg == "info msg"
     @test json.module == "Main"
     @test json.line isa Int
-    @test json.kwargs.x == [1, 2, 3]
-    @test json.kwargs.y == Dict(:hi => Dict(:hi2 => [1,2]))
+    # not tucked under `kwargs`
+    @test json.x == "[1, 2, 3]"
+    @test json.y == "(1, 2)"
 
-    # Fallback to strings
+
+    # With clash
+    io = IOBuffer()
+    with_logger(FormatLogger(JSON(; nest_kwargs=false), io)) do
+        @info "info msg" line = [1, 2, 3]
+    end
+    json = JSON3.read(seekstart(io))
+    @test json.level == "info"
+    @test json.msg == "info msg"
+    @test json.module == "Main"
+    @test json.line isa Int
+    # key was renamed to prevent clash:
+    @test json._line == "[1, 2, 3]"
+
+    # `recursive=true`
     io = IOBuffer()
     with_logger(FormatLogger(JSON(; recursive=true), io)) do
-        y = (1, 2)
-        @info "info msg" x = [1, 2, 3] y = Dict("hi" => NaN)
+        @info "info msg" x = [1, 2, 3] y = Dict("hi" => Dict("hi2" => [1,2]))
     end
     json = JSON3.read(seekstart(io))
     @test json.level == "info"
     @test json.msg == "info msg"
     @test json.module == "Main"
     @test json.line isa Int
-    @test json.kwargs.x == "[1, 2, 3]"
-    y = json.kwargs.y
-    must_have = ("Dict", "\"hi\"", "=>", "NaN")
-    @test all(h -> occursin(h, y), must_have) # avoid issues with printing changing with versions
-    @test json.kwargs[Symbol("LoggingFormats.FormatError")] == "NaN not allowed to be written in JSON spec"
+    @test json.kwargs.x == [1, 2, 3]
+    @test json.kwargs.y == Dict(:hi => Dict(:hi2 => [1,2]))
+
+    # Fallback to strings
+    for nest_kwargs in (true, false)
+        io = IOBuffer()
+        with_logger(FormatLogger(JSON(; recursive=true, nest_kwargs=nest_kwargs), io)) do
+            @info "info msg" x = [1, 2, 3] y = Dict("hi" => NaN)
+        end
+        json = JSON3.read(seekstart(io))
+        @test json.level == "info"
+        @test json.msg == "info msg"
+        @test json.module == "Main"
+        @test json.line isa Int
+        if nest_kwargs
+            @test json.kwargs.x == "[1, 2, 3]"
+            @test json.kwargs[Symbol("LoggingFormats.FormatError")] == "NaN not allowed to be written in JSON spec"
+            y = json.kwargs.y
+        else
+            @test json.x == "[1, 2, 3]"
+            @test json[Symbol("LoggingFormats.FormatError")] == "NaN not allowed to be written in JSON spec"
+            y = json.y
+        end
+        must_have = ("Dict", "\"hi\"", "=>", "NaN")
+        @test all(h -> occursin(h, y), must_have) # avoid issues with printing changing with versions
+    end
 
     # Test logging exceptions
-    for recursive in (false, true)
+    for recursive in (false, true), nest_kwargs in (true, false)
         # no stacktrace
         io = IOBuffer()
-        with_logger(FormatLogger(JSON(; recursive=recursive), io)) do
+        with_logger(FormatLogger(JSON(; recursive=recursive, nest_kwargs=nest_kwargs), io)) do
             @error "Oh no" exception = ArgumentError("no")
         end
         logs = JSON3.read(seekstart(io))
         @test logs["msg"] == "Oh no"
-        @test logs["kwargs"]["exception"] == "ArgumentError: no"
+        ex = nest_kwargs ? logs["kwargs"]["exception"] : logs["exception"]
+        @test ex == "ArgumentError: no"
 
         # non-standard exception key
         io = IOBuffer()
-        with_logger(FormatLogger(JSON(; recursive=recursive), io)) do
+        with_logger(FormatLogger(JSON(; recursive=recursive, nest_kwargs=nest_kwargs), io)) do
             @error "Oh no" ex = ArgumentError("no")
         end
         logs = JSON3.read(seekstart(io))
         @test logs["msg"] == "Oh no"
-        @test logs["kwargs"]["ex"] == "ArgumentError: no"
+        ex = nest_kwargs ? logs["kwargs"]["ex"] : logs["ex"]
+        @test ex == "ArgumentError: no"
 
         # stacktrace
         io = IOBuffer()
-        with_logger(FormatLogger(JSON(; recursive=recursive), io)) do
+        with_logger(FormatLogger(JSON(; recursive=recursive, nest_kwargs=nest_kwargs), io)) do
             try
                 throw(ArgumentError("no"))
             catch e
@@ -161,10 +199,10 @@ end
         logs = JSON3.read(seekstart(io))
         @test logs["msg"] == "Oh no"
 
-        @test occursin("ArgumentError: no", logs["kwargs"]["exception"])
+        ex = nest_kwargs ? logs["kwargs"]["exception"] : logs["exception"]
+        @test occursin("ArgumentError: no", ex)
         # Make sure we get a stacktrace out:
-        @test occursin(r"ArgumentError: no\nStacktrace:\s* \[1\]",
-                    logs["kwargs"]["exception"])
+        @test occursin(r"ArgumentError: no\nStacktrace:\s* \[1\]", ex)
     end
 end