Merge pull request #17 from PagoPlus/feat/allow-wasm-binary-path-on-config

[FEAT] Allow wasm binary path on config

Author: fermuch

README.md

@@ -28,10 +28,12 @@ and you can override the default version.
 Available configurations:
 - `:version` the binary release version to use (see [numscript-wasm releases](https://github.com/PagoPlus/numscript-wasm/releases/)).
 - `:retries` number of times to retry the download in case of a network failure.
+- `:binary_path` where the WASM binary file will be downloaded
 
 Ex:
 ```elixir
 config :numscriptex,
+       binary_path: :numscriptex |> :code.priv_dir() |> Path.join("numscript.wasm")
        version: "0.0.2",
        retries: 3
 ```

config/config.exs

@@ -0,0 +1,4 @@
+import Config
+
+config :numscriptex,
+  binary_path: System.get_env("NUMSCRIPTEX_BINARY_PATH")

lib/numscriptex/assets_manager.ex

@@ -10,26 +10,35 @@ defmodule Numscriptex.AssetsManager do
   @retries Application.compile_env(:numscriptex, :retries, 3)
   @numscript_checksums_url "https://github.com/PagoPlus/numscript-wasm/releases/download/v#{@numscript_wasm_version}/numscript_checksums.txt"
   @numscript_wasm_url "https://github.com/PagoPlus/numscript-wasm/releases/download/v#{@numscript_wasm_version}/numscript.wasm"
-  @binary_path :numscriptex
-               |> :code.priv_dir()
-               |> Path.join("numscript.wasm")
-               |> to_charlist()
+
+  @default_binary_path :numscriptex
+                       |> :code.priv_dir()
+                       |> Path.join("numscript.wasm")
+                       |> to_charlist()
 
   defmacro ensure_wasm_binary_is_valid do
     quote do
       require Logger
 
       File.mkdir_p!(:code.priv_dir(:numscriptex))
 
-      if File.exists?(unquote(@binary_path)) do
+      if File.exists?(unquote(binary_path())) do
         unquote(maybe_retry_download(compare_checksums()))
       else
         unquote(maybe_retry_download(download_and_compare_binary()))
       end
     end
   end
 
-  def binary_path, do: @binary_path
+  def binary_path do
+    path = Application.get_env(:numscriptex, :binary_path, @default_binary_path)
+
+    if !is_nil(path) && path != "" do
+      to_charlist(path)
+    else
+      @default_binary_path
+    end
+  end
 
   def hash_wasm_binary do
     # Logic explanation:
@@ -42,7 +51,7 @@ defmodule Numscriptex.AssetsManager do
     #   3. Uses `:crypto.hash_final/1` to finalize the streaming hash calculation;
     #   4. Encode the hash to the hexadecimal base (also the same as the checksums).
     quote do
-      File.stream!(unquote(@binary_path), 1024)
+      File.stream!(unquote(binary_path()), 1024)
       |> Enum.reduce(:crypto.hash_init(:sha256), fn line, acc ->
         :crypto.hash_update(acc, line)
       end)
@@ -124,7 +133,7 @@ defmodule Numscriptex.AssetsManager do
           :get,
           {unquote(@numscript_wasm_url), []},
           [],
-          stream: unquote(@binary_path)
+          stream: unquote(binary_path())
         )
 
       case request do
@@ -138,7 +147,7 @@ defmodule Numscriptex.AssetsManager do
 
         {:error, reason} ->
           Logger.error(
-            "Failed to download Numscript-WASM binary. Reason: #{inspect(reason)}. Binary path: #{unquote(@binary_path)}"
+            "Failed to download Numscript-WASM binary. Reason: #{inspect(reason)}. Binary path: #{unquote(binary_path())}"
           )
 
           raise CompileError
@@ -148,7 +157,7 @@ defmodule Numscriptex.AssetsManager do
 
   defp maybe_delete_wasm_binary do
     quote do
-      case File.rm(unquote(@binary_path)) do
+      case File.rm(unquote(binary_path())) do
         :ok ->
           :ok
 

test/numscriptex/assets_manager_test.exs

@@ -61,5 +61,17 @@ defmodule Numscriptex.AssetsManagerTest do
 
       File.copy!(dest_path, binary_path)
     end
+
+    test "uses custom binary path when configured" do
+      new_binary_path = System.tmp_dir() |> Path.join("test_binary.wasm") |> to_charlist()
+
+      refute AssetsManager.binary_path() == new_binary_path
+
+      Application.put_env(:numscriptex, :binary_path, new_binary_path)
+
+      assert AssetsManager.binary_path() == new_binary_path
+
+      on_exit(fn -> Application.delete_env(:numscriptex, :binary_path) end)
+    end
   end
 end