fix: tarball URL and download fallback for process injection

- Fix tarball URL from runpod/flash-worker to runpod-workers/flash
  (matching the actual GitHub repo path)
- Add python3 urllib.request fallback in download chain for base images
  without curl or wget (e.g. pytorch/pytorch runtime images)
- Update test assertions for URL and fallback chain

Author: deanq

src/runpod_flash/core/resources/constants.py

@@ -40,7 +40,7 @@ def _endpoint_domain_from_base_url(base_url: str) -> str:
 FLASH_WORKER_VERSION = os.environ.get("FLASH_WORKER_VERSION", "1.1.1")
 FLASH_WORKER_TARBALL_URL_TEMPLATE = os.environ.get(
     "FLASH_WORKER_TARBALL_URL",
-    "https://github.com/runpod/flash-worker/releases/download/"
+    "https://github.com/runpod-workers/flash/releases/download/"
     "v{version}/flash-worker-v{version}-py3.11-linux-x86_64.tar.gz",
 )
 

src/runpod_flash/core/resources/injection.py

@@ -39,7 +39,12 @@ def build_injection_cmd(
         "else "
         "mkdir -p $FW_DIR; "
         f'DL_URL="{tarball_url}"; '
-        '(command -v curl >/dev/null 2>&1 && curl -sSL "$DL_URL" || wget -qO- "$DL_URL") '
+        "dl() { "
+        '(command -v curl >/dev/null 2>&1 && curl -sSL "$1" || '
+        'command -v wget >/dev/null 2>&1 && wget -qO- "$1" || '
+        'python3 -c "import urllib.request,sys;sys.stdout.buffer.write(urllib.request.urlopen(sys.argv[1]).read())" "$1"); '
+        "}; "
+        'dl "$DL_URL" '
         "| tar xz -C $FW_DIR --strip-components=1; "
         # Cache to network volume if available
         "if [ -d /runpod-volume ]; then "

tests/unit/resources/test_injection.py

@@ -12,7 +12,7 @@ def test_default_remote_url(self):
 
         assert cmd.startswith("bash -c '")
         assert "FW_VER=1.1.1" in cmd
-        assert "flash-worker/releases/download/v1.1.1/" in cmd
+        assert "runpod-workers/flash/releases/download/v1.1.1/" in cmd
         assert "bootstrap.sh'" in cmd
 
     def test_custom_tarball_url(self):
@@ -50,12 +50,13 @@ def test_network_volume_caching(self):
         assert "/runpod-volume/.flash-worker/" in cmd
         assert "NV_CACHE" in cmd
 
-    def test_curl_wget_fallback(self):
-        """Test curl/wget fallback logic."""
+    def test_curl_wget_python_fallback(self):
+        """Test curl/wget/python3 fallback chain."""
         cmd = build_injection_cmd(worker_version="1.0.0")
 
         assert "curl -sSL" in cmd
         assert "wget -qO-" in cmd
+        assert "urllib.request" in cmd
 
     def test_default_uses_constants(self):
         """Test that calling with no args uses module-level constants."""