populate os.environ at runtime

Since Python populates `os.environ` in the Wizer init function, we need to clear
that out and replace it with the runtime environment prior to calling into the
app.

Signed-off-by: Joel Dice <[email protected]>

Author: dicej

Makefile

@@ -1,10 +1,10 @@
 .PHONY: build
 build: target/config.txt target/lib
 	PYO3_CONFIG_FILE=$$(pwd)/target/config.txt cargo build --release --target=wasm32-wasi
-	wasi-vfs/target/release/wasi-vfs pack target/wasm32-wasi/release/python_wasi.wasm \
+	env -i wasi-vfs/target/release/wasi-vfs pack target/wasm32-wasi/release/python_wasi.wasm \
 		--mapdir lib::$$(pwd)/target/lib \
 		-o target/wasm32-wasi/release/python-wasi-vfs.wasm
-	PYTHONUNBUFFERED=1 PYTHONPATH=/py wizer target/wasm32-wasi/release/python-wasi-vfs.wasm \
+	env -i PYTHONUNBUFFERED=1 PYTHONPATH=/py $$(which wizer) target/wasm32-wasi/release/python-wasi-vfs.wasm \
 		--inherit-env true --wasm-bulk-memory true --allow-wasi --dir py \
 		-o target/wasm32-wasi/release/python-wasi-vfs-wizer.wasm
 

py/app.py

@@ -1,10 +1,13 @@
 from spin_http import Request, Response, http_send
 from spin_redis import redis_get, redis_set
 from spin_config import config_get
+from os import environ
 
 def handle_request(request):
     print(f"Got request URI: {request.uri}")
 
+    print(f"Here's my environment: {environ}")
+
     response = http_send(Request("GET", "https://some-random-api.ml/facts/dog", [], None))
     print(f"Got dog fact: {str(response.body, 'utf-8')}")
 

spin.toml

@@ -7,6 +7,7 @@ version = "0.1.0"
 
 [[component]]
 id = "spin-webrtc"
+environment = { hello = "teapot" }
 config = { redis_address = "redis://127.0.0.1:6379" }
 source = "target/wasm32-wasi/release/python-wasi-vfs-wizer.wasm"
 allowed_http_hosts = ["insecure:allow-all"]

src/lib.rs

@@ -7,19 +7,20 @@ use {
     once_cell::unsync::OnceCell,
     pyo3::{
         exceptions::PyAssertionError,
-        types::{PyBytes, PyModule},
+        types::{PyBytes, PyMapping, PyModule},
         Py, PyErr, PyObject, PyResult, Python,
     },
     spin_sdk::{
         config,
         http::{Request, Response},
         outbound_http, redis,
     },
-    std::{ops::Deref, str},
+    std::{env, ops::Deref, str},
 };
 
 thread_local! {
     static HANDLE_REQUEST: OnceCell<PyObject> = OnceCell::new();
+    static ENVIRON: OnceCell<Py<PyMapping>> = OnceCell::new();
 }
 
 fn bytes(py: Python<'_>, src: &[u8]) -> PyResult<Py<PyBytes>> {
@@ -203,6 +204,24 @@ fn do_init() -> Result<()> {
             cell.set(py.import("app")?.getattr("handle_request")?.into())
                 .unwrap();
 
+            Ok::<_, PyErr>(())
+        })?;
+
+        ENVIRON.with(|cell| {
+            let environ = py
+                .import("os")?
+                .getattr("environ")?
+                .downcast::<PyMapping>()
+                .unwrap();
+
+            let keys = environ.keys()?;
+
+            for i in 0..keys.len()? {
+                environ.del_item(keys.get_item(i)?)?;
+            }
+
+            cell.set(environ.into()).unwrap();
+
             Ok(())
         })
     })
@@ -242,6 +261,16 @@ fn handle(request: Request) -> Result<Response> {
                 .transpose()?,
         };
 
+        ENVIRON.with(|cell| {
+            let environ = cell.get().unwrap().as_ref(py);
+
+            for (k, v) in env::vars() {
+                environ.set_item(k, v)?;
+            }
+
+            Ok::<(), PyErr>(())
+        })?;
+
         let response = HANDLE_REQUEST.with(|cell| {
             cell.get()
                 .unwrap()