Pull over the retry script that just landed in GTMSessionFetcher.

.github/workflows/retry.sh

@@ -0,0 +1,91 @@
+#!/bin/bash
+
+# A generic retry script that runs a command and retries it if it fails
+# and the output matches a specific pattern.
+
+set -eu
+set -o pipefail
+
+MAX_RETRIES=1
+PATTERN="Unable to find a device matching the provided destination specifier"
+DELAY=10
+
+# Parse arguments
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --max-retries)
+      MAX_RETRIES="$2"
+      shift 2
+      ;;
+    --pattern)
+      PATTERN="$2"
+      shift 2
+      ;;
+    --delay)
+      DELAY="$2"
+      shift 2
+      ;;
+    --)
+      shift
+      break
+      ;;
+    *)
+      echo "Unknown option: $1"
+      exit 1
+      ;;
+  esac
+done
+
+if [ $# -eq 0 ]; then
+  echo "Usage: $0 [--max-retries N] [--pattern PATTERN] [--delay SECONDS] -- COMMAND [ARGS...]"
+  exit 1
+fi
+
+if [ -z "$PATTERN" ]; then
+  echo "Error: A non-empty pattern is required to identify transient failures." >&2
+  exit 1
+fi
+
+COMMAND=("$@")
+
+ATTEMPT=0
+MAX_ATTEMPTS=$((MAX_RETRIES + 1))
+
+while [ $ATTEMPT -lt $MAX_ATTEMPTS ]; do
+  ATTEMPT=$((ATTEMPT + 1))
+  if [ $ATTEMPT -gt 1 ]; then
+    echo "Attempt $ATTEMPT of $MAX_ATTEMPTS (Retry $((ATTEMPT - 1)) of $MAX_RETRIES)..."
+  fi
+
+  # We need to capture the output to check for the pattern, but also stream it.
+  # We'll use a temp file for the log.
+  LOG_FILE=$(mktemp)
+
+  # Run the command
+  set +e
+  "${COMMAND[@]}" 2>&1 | tee "$LOG_FILE"
+  STATUS=$?
+  set -e
+
+  if [ $STATUS -eq 0 ]; then
+    rm -f "$LOG_FILE"
+    exit 0
+  fi
+
+  # Check if the failure matches the required pattern.
+  SHOULD_RETRY=false
+  if grep -q "$PATTERN" "$LOG_FILE"; then
+    echo "Warning: Command failed and output matched pattern: '$PATTERN'"
+    SHOULD_RETRY=true
+  fi
+
+  rm -f "$LOG_FILE"
+
+  if [ "$SHOULD_RETRY" = true ] && [ $ATTEMPT -lt $MAX_ATTEMPTS ]; then
+    echo "Retrying in $DELAY seconds..."
+    sleep "$DELAY"
+  else
+    exit $STATUS
+  fi
+done
+

.github/workflows/swiftpm.yml

@@ -8,6 +8,7 @@ on:
     - 'UnitTests/**'
     - 'Package*.swift'
     - 'SwiftPMTests/**'
+    - '.github/workflows/retry.sh'
     - '.github/workflows/swiftpm.yml'
   pull_request:
     branches: [ main ]
@@ -16,6 +17,7 @@ on:
     - 'UnitTests/**'
     - 'Package*.swift'
     - 'SwiftPMTests/**'
+    - '.github/workflows/retry.sh'
     - '.github/workflows/swiftpm.yml'
   schedule:
     # Run the first and fifteenth of every month at 6:12 UTC
@@ -71,7 +73,8 @@ jobs:
             ;;
         esac
 
-        xcodebuild \
+        .github/workflows/retry.sh -- \
+          xcodebuild \
             -scheme GoogleAPIClientForREST-Package \
             -configuration ${{ matrix.CONFIGURATION }} \
             -destination "${DESTINATION}" \