Make TimeZones.jl and Syslogs.jl optional dependencies

Project.toml

@@ -7,22 +7,24 @@ version = "1.3.0"
 [deps]
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
-JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
+Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 Serialization = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
 Sockets = "6462fe0b-24de-5631-8697-dd941f90decc"
-Syslogs = "cea106d9-e007-5e6c-ad93-58fe2094e9c4"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
-TimeZones = "f269a46b-ccf7-5d73-abea-4c690281aa53"
 UUIDs = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
 
 [compat]
 JSON = "0.16.1, 0.17, 0.18, 0.19, 0.20, 0.21"
+Requires = "1"
 Syslogs = "0.0.1, 0.1, 0.2, 0.3"
 TimeZones = "0.7, 0.8, 0.9, 0.10, 0.11, 1"
 julia = "1"
 
 [extras]
+JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
 Suppressor = "fd094767-a336-5f1f-9728-57cf17d0bbfb"
+Syslogs = "cea106d9-e007-5e6c-ad93-58fe2094e9c4"
+TimeZones = "f269a46b-ccf7-5d73-abea-4c690281aa53"
 
 [targets]
-test = ["Suppressor"]
+test = ["JSON", "Suppressor", "Syslogs", "TimeZones"]

src/Memento.jl

@@ -5,12 +5,9 @@ using UUIDs
 using Dates
 using Sockets
 using Distributed
+using Requires
 using Serialization
 
-using Syslogs
-using JSON
-using TimeZones
-
 # We're often extending these methods
 import Base: error, log
 
@@ -45,7 +42,6 @@ include("filters.jl")
 include("formatters.jl")
 include("handlers.jl")
 include("loggers.jl")
-include("syslog.jl")
 include("stdlib.jl")
 include("config.jl")
 include("exceptions.jl")
@@ -64,6 +60,9 @@ const LOGGER = getlogger(@__MODULE__)
 function __init__()
     Memento.config!(DEFAULT_LOG_LEVEL)
     Memento.register(LOGGER)
+
+    @require TimeZones="f269a46b-ccf7-5d73-abea-4c690281aa53" include("tz.jl")
+    @require Syslogs="cea106d9-e007-5e6c-ad93-58fe2094e9c4" include("syslog.jl")
 end
 
 _precompile_()

src/formatters.jl

@@ -79,15 +79,7 @@ function format(fmt::DefaultFormatter, rec::Record)
 
                 value = string(" stack:[", join(str_frames, ", "), "]")
             elseif content === :date
-                value = if tmp_val isa ZonedDateTime
-                    # `localzone` is expensive, so we don't call it until it is required.
-                    tzout = fmt.output_tz === nothing ? localzone() : fmt.output_tz
-                    Dates.format(astimezone(tmp_val, tzout), fmt.date_fmt_string)
-                elseif tmp_val isa DateTime
-                    Dates.format(tmp_val, fmt.date_fmt_string)
-                else
-                    tmp_val
-                end
+                value = _format_datetime(tmp_val, fmt.date_fmt_string, fmt.output_tz)
             else
                 value = tmp_val
             end
@@ -172,3 +164,7 @@ function format(fmt::DictFormatter, rec::Record)
 
     return fmt.serializer(dict)
 end
+
+# This is overloaded to return a ZonedDateTime only when an output_tz is specified
+_format_datetime(dt, args...) = dt
+_format_datetime(dt::DateTime, fmt::AbstractString, tz::Nothing) = Dates.format(dt, fmt)

src/records.jl

@@ -120,7 +120,7 @@ NOTE: if you'd like more logging attributes you can:
 2. make a custom `Record` type.
 
 # Fields
-* `date::Attribute{ZonedDateTime}`: timestamp of log event
+* `date::Attribute{DateTime}`: timestamp of log event
 * `level::Attribute{AbstractString}`: log level
 * `levelnum::Attribute{Int}`: integer value for log level
 * `msg::Attribute{AbstractString}`: the log message itself
@@ -157,7 +157,7 @@ function DefaultRecord(name::AbstractString, level::AbstractString, levelnum::In
     trace = Attribute{StackTrace}(get_trace)
 
     DefaultRecord(
-        Attribute{ZonedDateTime}(() -> Dates.now(tz"UTC")),
+        Attribute{DateTime}(() -> Dates.now()),
         Attribute(level),
         Attribute(levelnum),
         Attribute{AbstractString}(msg),

src/syslog.jl

@@ -1,3 +1,5 @@
+using .Syslogs
+
 # This is necessary or Memento will attempt to use `println` with one argument (unsupported by Syslog)
 # This should be handled by optional dependency stuff in the future
 """

src/tz.jl

@@ -0,0 +1,17 @@
+using .TimeZones
+
+# We're just adding one timezone specific method for constructing and formatting a ZonedDateTime
+function _format_datetime(dt::DateTime, fmt::AbstractString, tz::Dates.TimeZone)
+    return Dates.format(ZonedDateTime(dt, tz), fmt)
+end
+
+# Since we already default to local zone in the base case explicitly convert a
+# ZonedDateTime to be consistent.
+function _format_datetime(zdt::ZonedDateTime, fmt::AbstractString, tz::Nothing)
+    return Dates.format(astimezone(zdt, localzone()), fmt)
+end
+
+# Convert ZonedDateTimes to a specified output tz
+function _format_datetime(zdt::ZonedDateTime, fmt::AbstractString, tz::Dates.TimeZone)
+    return Dates.format(astimezone(zdt, tz), fmt)
+end