From c426c23567f62a74a9d65944c8c449afc7ed0e3e Mon Sep 17 00:00:00 2001
From: Vlad Stan <stan.v.vlad@gmail.com>
Date: Wed, 24 Jun 2026 08:59:55 +0300
Subject: [PATCH] perf: cache wasm component

---
 lnbits/core/extensions/loader.py |  3 +++
 lnbits/core/extensions/wasm.py   | 26 +++++++++++++++++++++++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/lnbits/core/extensions/loader.py b/lnbits/core/extensions/loader.py
index 4a825d973..bbff64e97 100644
--- a/lnbits/core/extensions/loader.py
+++ b/lnbits/core/extensions/loader.py
@@ -44,6 +44,9 @@ def load_wasm_extension_config(ext_id: str) -> dict[str, Any] | None:
 
 def register_wasm_extension(app: FastAPI, ext_id: str) -> WasmExtension:
     loaded = load_wasm_extension(ext_id)
+    from .wasm import warm_wasm_extension
+
+    warm_wasm_extension(loaded)
     _mount_wasm_extension_static(app, loaded)
     _register_wasm_extension_routes(app, loaded)
     _register_wasm_extension_api_routes(app, loaded)
diff --git a/lnbits/core/extensions/wasm.py b/lnbits/core/extensions/wasm.py
index a2d28439c..0dd8ad688 100644
--- a/lnbits/core/extensions/wasm.py
+++ b/lnbits/core/extensions/wasm.py
@@ -35,6 +35,10 @@ async def invoke_wasm_extension_export(
     )
 
 
+def warm_wasm_extension(extension: WasmExtension) -> None:
+    _wasm_component(extension)
+
+
 def _invoke_wasm_extension_export_sync(
     extension: WasmExtension,
     export_name: str,
@@ -57,7 +61,7 @@ def _invoke_wasm_extension_export_sync(
     linker.add_wasip2()
     _add_extension_host_imports(linker, ExtensionAPIHost(api))
 
-    wasm_component = component.Component.from_file(engine, extension.module_path)
+    wasm_component = _wasm_component(extension)
     instance = linker.instantiate(store, wasm_component)
     function = instance.get_func(store, export_name)
     if not function:
@@ -83,6 +87,26 @@ def _wasm_engine() -> Any:
     return Engine(config)
 
 
+def _wasm_component(extension: WasmExtension) -> Any:
+    stat = extension.module_path.stat()
+    return _cached_wasm_component(
+        str(extension.module_path),
+        stat.st_mtime_ns,
+        stat.st_size,
+    )
+
+
+@lru_cache(maxsize=32)
+def _cached_wasm_component(
+    module_path: str,
+    mtime_ns: int,
+    size: int,
+) -> Any:
+    from wasmtime import component
+
+    return component.Component.from_file(_wasm_engine(), module_path)
+
+
 def _add_extension_host_imports(linker: Any, api_host: ExtensionAPIHost) -> None:
     with linker.root() as root:
         with root.add_instance("lnbits:extension/host") as host: