enable custom compiled lightgbm package

Project.toml

@@ -5,6 +5,7 @@ version = "0.4.3"
 [deps]
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
+Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
 MLJModelInterface = "e80e1ace-859a-464e-9ed9-23947d8ae3ea"
 StatsBase = "2913bbd2-ae8a-5f71-8c99-4fb6c76f3a91"
 

src/LightGBM.jl

@@ -1,13 +1,39 @@
 module LightGBM
 
 using Dates
-
+using Logging
 import Base
 import Libdl
 import StatsBase
+import Libdl
+
+struct LibraryNotFoundError <: Exception
+    msg::String
+end
+
+
+function find_library(library_name::String, custom_paths::Vector{String})
+
+    # Search system filedirs first, returns empty string if not found
+    output = Libdl.find_library(library_name)
+
+    if output == ""
+        # try specified paths
+        @info("$(library_name) not found in system dirs, trying fallback")
+        output = Libdl.find_library(library_name, custom_paths)
+    else
+        @info("$(library_name) found in system dirs!")
+    end
+
+    if output == ""
+        throw(LibraryNotFoundError("$(library_name) not found. Please ensure this library is either in system dirs or the dedicated paths: $(custom_paths)"))
+    end
+
+    return output
+
+end
 
-# we build it so we can assert it is present...
-const LGBM_library = abspath(joinpath(@__DIR__, "lib_lightgbm.$(Libdl.dlext)"))
+const LGBM_library = find_library("lib_lightgbm", [@__DIR__])
 
 include("wrapper.jl")
 include("estimators.jl")

test/basic/test_lightgbm.jl

@@ -0,0 +1,97 @@
+module TestLightGBM
+
+import Libdl
+using LightGBM
+using Test
+
+src_dir = abspath(joinpath(@__DIR__, "..", "..", "src"))
+
+# These set of tests use common libraries of each system to test `find_library` without having to modify env variables
+function setup_env()
+    output = Dict()
+
+    if Sys.islinux()
+        output["sample_lib"] = "libcrypt"
+    elseif Sys.isunix()
+        output["sample_lib"] = "libevent"
+    elseif Sys.iswindows()
+        output["sample_lib"] = "netmsg"
+    end
+
+    output["ref_path"] = joinpath(src_dir, "lib_lightgbm.$(Libdl.dlext)")
+    output["custom_fixture_path"] = joinpath(src_dir, "$(output["sample_lib"]).$(Libdl.dlext)")
+    output["lib_not_on_sys_fixture_path"] = joinpath(src_dir, "lib_not_on_sys.$(Libdl.dlext)")
+
+    return output
+
+end
+
+function teardown(settings::Dict)
+
+    rm(settings["custom_fixture_path"], force=true)
+    rm(settings["lib_not_on_sys_fixture_path"], force=true)
+
+    return nothing
+
+end
+
+@testset "find_library" begin
+
+    @testset "find_library works with no system lib" begin
+
+        # Arrange
+        settings = setup_env()
+        cp(settings["ref_path"], settings["lib_not_on_sys_fixture_path"]) # fake file copied from lightgbm
+
+        # Act
+        output = LightGBM.find_library("lib_not_on_sys", [src_dir])
+
+        # Assert
+        @test output == joinpath(src_dir, "lib_not_on_sys") # custom path detected (without extension)
+
+        teardown(settings)
+    end
+
+    @testset "find_library finds system lib first" begin
+
+        # Arrange
+        settings = setup_env()
+        cp(settings["ref_path"], settings["custom_fixture_path"]) # fake file copied from lightgbm
+
+        # Act
+        output = LightGBM.find_library(settings["sample_lib"], [src_dir])
+
+        # Assert
+        @test output == settings["sample_lib"] # sys lib detected
+
+        teardown(settings)
+    end
+
+    @testset "find_library finds system lib" begin
+
+        # Arrange
+        settings = setup_env()
+
+        # Act
+        output = LightGBM.find_library(settings["sample_lib"], [src_dir]) # sample_lib should only exist in syspath
+
+        # Assert
+        @test output == settings["sample_lib"]
+
+        teardown(settings)
+    end
+
+    @testset "find_library throws error if cannot find lib" begin
+
+        # Arrange
+        settings = setup_env()
+
+        # Act and assert
+        @test_throws LightGBM.LibraryNotFoundError LightGBM.find_library("lib_that_simply_doesnt_exist", [src_dir])
+
+        teardown(settings)
+
+    end
+end
+
+end # module

test/runtests.jl

@@ -73,6 +73,10 @@ end
         include(joinpath("basic", "test_search_cv.jl"))
     end
 
+    @testset "LightGBM" begin
+        include(joinpath("basic", "test_lightgbm.jl"))
+    end
+
 end
 
 @testset "Integration tests" begin