Use resilient wheel bootstrap sources

Author: EthanSteinberg

.github/scripts/run_cibuildwheel.py

@@ -28,7 +28,9 @@ def prefetch_windows_virtualenv() -> None:
     if cache_path.exists():
         return
 
-    url = f"https://github.com/pypa/get-virtualenv/releases/download/{version}/virtualenv.pyz"
+    # PyPA documents this CDN endpoint for the zipapp. It avoids depending on
+    # GitHub release assets merely to start cibuildwheel.
+    url = "https://bootstrap.pypa.io/virtualenv.pyz"
     cache_path.parent.mkdir(parents=True, exist_ok=True)
     temporary_path = cache_path.with_suffix(".tmp")
 

build/linux_setup.sh

@@ -1,12 +1,22 @@
 set -euo pipefail
 
-curl \
-    --fail \
-    --location \
-    --retry 8 \
-    --retry-all-errors \
-    --retry-delay 2 \
-    --connect-timeout 30 \
-    --output /tmp/meds-reader-bazelisk \
-    https://github.com/bazelbuild/bazelisk/releases/download/v1.27.0/bazelisk-linux-amd64
+download_succeeded=0
+for attempt in {1..8}; do
+    if curl \
+        --fail \
+        --location \
+        --connect-timeout 30 \
+        --max-time 120 \
+        --output /tmp/meds-reader-bazelisk \
+        https://github.com/bazelbuild/bazelisk/releases/download/v1.27.0/bazelisk-linux-amd64; then
+        download_succeeded=1
+        break
+    fi
+
+    if [ "$attempt" -lt 8 ]; then
+        sleep "$((attempt * 2))"
+    fi
+done
+
+test "$download_succeeded" -eq 1
 install -m 0755 /tmp/meds-reader-bazelisk /usr/local/bin/bazel