Introduce a Handler hierarchy and DictHandler

Project.toml

@@ -1,7 +1,7 @@
 name = "Checkpoints"
 uuid = "b4a3413d-e481-5afc-88ff-bdfbd6a50dce"
 authors = "Invenia Technical Computing Corporation"
-version = "0.3.20"
+version = "0.3.21"
 
 [deps]
 AWSS3 = "1c724243-ef5b-51ab-93f4-b0a88ac62a95"

src/Checkpoints.jl

@@ -29,7 +29,7 @@ __init__() = Memento.register(LOGGER)
 
 include("handler.jl")
 
-const CHECKPOINTS = Dict{String, Union{Nothing, String, Handler}}()
+const CHECKPOINTS = Dict{String, Union{Nothing, String, AbstractHandler}}()
 @contextvar CONTEXT_TAGS::Tuple{Vararg{Pair{Symbol, Any}}} = Tuple{}()
 
 include("session.jl")
@@ -75,7 +75,7 @@ available() = collect(keys(CHECKPOINTS))
 Returns a vector of all enabled ([`config`](@ref)ured) and not [`deprecate`](@ref)d checkpoints.
 Use [`deprecated_checkpoints`](@ref) to retrieve a mapping of old / deprecated checkpoints.
 """
-enabled_checkpoints() = filter(k -> CHECKPOINTS[k] isa Handler, available())
+enabled_checkpoints() = filter(k -> CHECKPOINTS[k] isa AbstractHandler, available())
 
 """
     deprecated_checkpoints() -> Dict{String, String}
@@ -130,31 +130,31 @@ function checkpoint(prefix::Union{Module, String}, name::String, args...; tags..
 end
 
 """
-    config(handler::Handler, labels::Vector{String})
-    config(handler::Handler, prefix::String)
+    config(handler::AbstractHandler, labels::Vector{String})
+    config(handler::AbstractHandler, prefix::String)
     config(labels::Vector{String}, args...; kwargs...)
     config(prefix::String, args...; kwargs...)
 
-Configures the specified checkpoints with a `Handler`.
-If the first argument is not a `Handler` then all `args` and `kwargs` are passed to a
-`Handler` constructor for you.
+Configures the specified checkpoints with a `AbstractHandler`.
+If the first argument is not an `AbstractHandler` then all `args` and `kwargs` are
+passed to a `JLSOHandler` constructor for you.
 """
-function config(handler::Handler, names::Vector{String})
+function config(handler::AbstractHandler, names::Vector{String})
     for n in names
         _config(handler, n)
     end
 end
 
-function config(handler::Handler, prefix::Union{Module, String})
+function config(handler::AbstractHandler, prefix::Union{Module, String})
     config(handler, filter(l -> startswith(l, prefix), available()))
 end
 
 function config(names::Vector{String}, args...; kwargs...)
-    config(Handler(args...; kwargs...), names)
+    config(JLSOHandler(args...; kwargs...), names)
 end
 
 function config(prefix::Union{Module, String}, args...; kwargs...)
-    config(Handler(args...; kwargs...), prefix)
+    config(JLSOHandler(args...; kwargs...), prefix)
 end
 
 # To avoid collisions with `prefix` method above, which should probably use

src/deprecated.jl

@@ -11,3 +11,5 @@ function checkpoint_deprecation(tags...)
         :checkpoint
     )
 end
+
+Base.@deprecate_binding Handler JLSOHandler

src/handler.jl

@@ -1,56 +1,82 @@
-struct Handler{P<:AbstractPath}
-    path::P
-    settings        # Could be Vector or Pairs on 0.6 or 1.0 respectively
-end
+abstract type AbstractHandler end
 
 """
-    Handler(path::Union{String, AbstractPath}; kwargs...)
-    Handler(bucket::String, prefix::String; kwargs...)
+    getkey(handler, name, separator="/") -> String
 
-Handles iteratively saving JLSO file to the specified path location.
-FilePath are used to abstract away differences between paths on S3 or locally.
+Combine the `CONTEXT_TAGS` and `name` into a unique checkpoint key as a string.
+If the checkpoint name includes `.`, usually representing nested modules, these are
+also replaced with the provided separator.
 """
-Handler(path::AbstractPath; kwargs...) = Handler(path, kwargs)
-Handler(path::String; kwargs...) = Handler(Path(path), kwargs)
-Handler(bucket::String, prefix::String; kwargs...) = Handler(S3Path("s3://$bucket/$prefix"), kwargs)
+function getkey(::AbstractHandler, name::String, separator="/")::String
+    prefix = ["$key=$val" for (key, val) in CONTEXT_TAGS[]]
+    parts = split(name, '.')  # Split up the name by '.'
+    return Base.join(vcat(prefix, parts), separator)
+end
 
-"""
-    path(handler, name)
+path(args...) = Path(getkey(args...))
 
-Determines the path to save to based on the handlers path prefix, name, and context.
-Tags are used to dynamically prefix the named file with the handler's path.
-Names with a '.' separators will be used to form subdirectories
-(e.g., "Foo.bar.x" will be saved to "\$prefix/Foo/bar/x.jlso").
 """
-function path(handler::Handler{P}, name::String) where P
-    prefix = ["$key=$val" for (key,val) in CONTEXT_TAGS[]]
+    stage!(handler::AbstractHandler, objects, data::Dict{Symbol})
 
-    # Split up the name by '.' and add the jlso extension
-    parts = split(name, '.')
-    parts[end] = string(parts[end], ".jlso")
+Update the objects with the new data.
+By default all handlers assume objects implements the associative interface.
+"""
+function stage!(handler::AbstractHandler, objects, data::Dict{Symbol})
+    for (k, v) in data
+        objects[k] = v
+    end
 
-    return join(handler.path, prefix..., parts...)
+    return objects
 end
 
 """
-    stage!(handler::Handler, jlso::JLSOFIle, data::Dict{Symbol})
+    commit!(handler, prefix, objects)
 
-Update the JLSOFile with the new data.
+Serialize and write objects to a given path/prefix/key as defined by the handler.
 """
-function stage!(handler::Handler, jlso::JLSO.JLSOFile, data::Dict{Symbol})
-    for (k, v) in data
-        jlso[k] = v
+commit!
+
+#=
+Define our no-op conditions just to be safe
+=#
+function checkpoint(handler::Nothing, name::String, data::Dict{Symbol}; tags...)
+    checkpoint_deprecation(tags...)
+    with_checkpoint_tags(tags...) do
+        debug(LOGGER, "Checkpoint $name triggered, but no handler has been set.")
+        nothing
     end
+end
+
 
-    return jlso
+struct JLSOHandler{P<:AbstractPath} <: AbstractHandler
+    path::P
+    settings        # Could be Vector or Pairs on 0.6 or 1.0 respectively
 end
 
 """
-    commit!(handler, path, jlso)
+    JLSOHandler(path::Union{String, AbstractPath}; kwargs...)
+    JLSOHandler(bucket::String, prefix::String; kwargs...)
+
+Handles iteratively saving JLSO file to the specified path location.
+FilePath are used to abstract away differences between paths on S3 or locally.
+"""
+JLSOHandler(path::AbstractPath; kwargs...) = JLSOHandler(path, kwargs)
+JLSOHandler(path::String; kwargs...) = JLSOHandler(Path(path), kwargs)
+JLSOHandler(bucket::String, prefix::String; kwargs...) = JLSOHandler(S3Path("s3://$bucket/$prefix"), kwargs)
+
+"""
+    path(handler, name)
 
-Write the JLSOFile to the path as bytes.
+Determines the path to save to based on the handlers path prefix, name, and context.
+Tags are used to dynamically prefix the named file with the handler's path.
+Names with a '.' separators will be used to form subdirectories
+(e.g., "Foo.bar.x" will be saved to "\$prefix/Foo/bar/x.jlso").
 """
-function commit!(handler::Handler{P}, path::P, jlso::JLSO.JLSOFile) where P <: AbstractPath
+function path(handler::JLSOHandler{P}, name::String) where P
+    return join(handler.path, getkey(handler, name) * ".jlso")
+end
+
+function commit!(handler::JLSOHandler{P}, path::P, jlso::JLSO.JLSOFile) where P <: AbstractPath
     # NOTE: This is only necessary because FilePathsBase.FileBuffer needs to support
     # write(::FileBuffer, ::UInt8)
     # https://github.com/rofinn/FilePathsBase.jl/issues/45
@@ -61,7 +87,7 @@ function commit!(handler::Handler{P}, path::P, jlso::JLSO.JLSOFile) where P <: A
     write(path, bytes)
 end
 
-function checkpoint(handler::Handler, name::String, data::Dict{Symbol}; tags...)
+function checkpoint(handler::JLSOHandler, name::String, data::Dict{Symbol}; tags...)
     checkpoint_deprecation(tags...)
     with_checkpoint_tags(tags...) do
         debug(LOGGER, "Checkpoint $name triggered, with context: $(join(CONTEXT_TAGS[], ", ")).")
@@ -72,13 +98,24 @@ function checkpoint(handler::Handler, name::String, data::Dict{Symbol}; tags...)
     end
 end
 
-#=
-Define our no-op conditions just to be safe
-=#
-function checkpoint(handler::Nothing, name::String, data::Dict{Symbol}; tags...)
+"""
+    DictHandler(objects)
+
+Saves checkpointed objects into a dictionary where the keys are strings generated from
+the checkpoint tags and name.
+"""
+struct DictHandler <: AbstractHandler
+    objects::Dict{String, Dict}
+    DictHandler() = new(Dict{String, Dict}())
+end
+
+commit!(handler::DictHandler, k::AbstractString, data) = setindex!(handler.objects, data, k)
+
+function checkpoint(handler::DictHandler, name::String, data::Dict{Symbol}; tags...)
+    # TODO: Remove duplicate wrapper code
     checkpoint_deprecation(tags...)
     with_checkpoint_tags(tags...) do
-        debug(LOGGER, "Checkpoint $name triggered, but no handler has been set.")
-        nothing
+        debug(LOGGER, "Checkpoint $name triggered, with context: $(join(CONTEXT_TAGS[], ", ")).")
+        handler.objects[getkey(handler, name)] = data
     end
 end

src/session.jl

@@ -1,4 +1,4 @@
-struct Session{H<:Union{Nothing, Handler}}
+struct Session{H<:Union{Nothing, AbstractHandler}}
     name::String
     handler::H
     objects::DefaultDict
@@ -8,11 +8,7 @@ function Session(name::String)
      # Create our objects dictionary which defaults to returning
     # an empty JLSOFile
     handler = CHECKPOINTS[name]
-
-    objects = DefaultDict{AbstractPath, JLSO.JLSOFile}() do
-        JLSO.JLSOFile(Dict{Symbol, Vector{UInt8}}(); handler.settings...)
-    end
-
+    objects = session_objects(handler)
     Session{typeof(handler)}(name, handler, objects)
 end
 
@@ -34,29 +30,45 @@ function Session(f::Function, prefix::Union{Module, String}, names::Vector{Strin
     Session(f, map(n -> "$prefix.$n", names))
 end
 
+function session_objects(handler)
+    return DefaultDict{AbstractString, Dict}() do
+        Dict{Symbol, Any}()
+    end
+end
+
+function session_objects(handler::JLSOHandler)
+    return DefaultDict{AbstractPath, JLSO.JLSOFile}() do
+        JLSO.JLSOFile(Dict{Symbol, Vector{UInt8}}(); handler.settings...)
+    end
+end
+
 """
     commit!(session)
 
-Write all staged JLSOFiles to the respective paths.
+Write all staged objects to the respective keys.
 """
 function commit!(session::Session)
     # No-ops skip when handler is nothing
     session.handler === nothing && return nothing
 
-    for (p, jlso) in session.objects
-        commit!(session.handler, p, jlso)
+    for (k, v) in session.objects
+        commit!(session.handler, k, v)
     end
 end
 
 function checkpoint(session::Session, data::Dict{Symbol}; tags...)
     checkpoint_deprecation(tags...)
     with_checkpoint_tags(tags...) do
+        handler = session.handler
+        name = session.name
+        K = keytype(session.objects)
+
         # No-ops skip when handler is nothing
-        session.handler === nothing && return nothing
+        handler === nothing && return nothing
 
-        p = path(session.handler, session.name)
-        jlso = session.objects[p]
-        session.objects[p] = stage!(session.handler, jlso, data)
+        # Our handler may not always be storing data in filepaths
+        k = K <: AbstractPath ? path(handler, name) : getkey(handler, name)
+        session.objects[k] = stage!(handler, session.objects[k], data)
     end
 end
 

test/runtests.jl

@@ -10,6 +10,7 @@ using Test
 using AWS: AWSConfig
 using AWSS3: S3Path, s3_put, s3_list_buckets, s3_create_bucket
 using Tables: Tables
+using Checkpoints: JLSOHandler, DictHandler
 
 Distributed.addprocs(5)
 @everywhere using Checkpoints
@@ -256,5 +257,40 @@ Distributed.addprocs(5)
                 @test data[:data] == b
             end
         end
+
+        # We're largely reusing the same code for different handlers, but make sure
+        # that saving to a dict also works.
+        @testset "DictHandler" begin
+            a = Dict(zip(
+                map(x -> Symbol(randstring(4)), 1:10),
+                map(x -> rand(10), 1:10)
+            ))
+            b = rand(10)
+            handler = DictHandler()
+            objects = handler.objects
+            Checkpoints.config(handler, "TestPkg")
+
+            @test isempty(handler.objects)
+            TestPkg.foo(x, y)
+            @test haskey(objects, "TestPkg/foo")
+            @test issetequal(keys(objects["TestPkg/foo"]), [:x, :y])
+            @test objects["TestPkg/foo"][:x] == x
+            @test objects["TestPkg/foo"][:y] == y
+
+            TestPkg.bar(b)
+            @test haskey(objects, "date=2017-01-01/TestPkg/bar")
+            @test objects["date=2017-01-01/TestPkg/bar"][:data] == b
+
+            TestPkg.baz(a)
+            @test haskey(objects, "TestPkg/baz")
+            @test objects["TestPkg/baz"] == a
+
+            TestPkg.qux(a, b)
+            @test haskey(objects, "TestPkg/qux_a")
+            @test objects["TestPkg/qux_a"] == a
+
+            @test haskey(objects, "TestPkg/qux_b")
+            @test objects["TestPkg/qux_b"][:data] == b
+        end
     end
 end