ci: only build baseline if we cannot find a wheel anywhere for it

.gitlab/benchmarks/steps/build-baseline.sh

@@ -2,20 +2,37 @@
 set -e -o pipefail
 
 # If we have a tag (e.g. v2.21.1), then use the PyPI published wheel
-# Otherwise, build the wheel from commit hash
 if [[ -n "${BASELINE_TAG}" ]];
 then
+  echo "Downloading wheel for tag ${BASELINE_TAG} from PyPI"
   python3.9 -m pip download --no-deps "ddtrace==${BASELINE_TAG:1}"
-else
-  ulimit -c unlimited
-  curl -sSf https://sh.rustup.rs | sh -s -- -y;
-  export PATH="$HOME/.cargo/bin:$PATH"
-  echo "Building wheel for ${BASELINE_BRANCH}:${BASELINE_COMMIT_SHA}"
-  git checkout "${BASELINE_COMMIT_SHA}"
-  mkdir ./tmp
-  PYO3_PYTHON=python3.9 CIBW_BUILD=1 python3.9 -m pip wheel --no-deps -w ./tmp/ ./
-  for wheel in ./tmp/*.whl;
-  do
-    auditwheel repair "$wheel" --plat "manylinux2014_x86_64" -w ./
-  done
+  exit 0
 fi
+
+
+# If we have a commit SHA, try to download the prebuild wheel from GitHub Actions
+if [[ -n "${BASELINE_COMMIT_SHA}" ]];
+then
+  # Try to download the wheel from the public S3 bucket if we have one
+  PIPELINE_ID=$(.gitlab/scripts/get-pipelines-for-ref.sh "${BASELINE_COMMIT_SHA}" | jq -r 'if length > 0 then .[0].id else empty end')
+
+  if [[ -n "${PIPELINE_ID}" ]];
+  then
+    echo "Downloading prebuilt wheel for ${BASELINE_BRANCH}:${BASELINE_COMMIT_SHA} from pipeline ${PIPELINE_ID}"
+    python3.9 -m pip download --no-deps --index-url "https://dd-trace-py-builds.s3.amazonaws.com/${PIPELINE_ID}/" "ddtrace"
+    exit 0
+  fi
+fi
+
+# Otherwise, build from source
+ulimit -c unlimited
+curl -sSf https://sh.rustup.rs | sh -s -- -y;
+export PATH="$HOME/.cargo/bin:$PATH"
+echo "Building wheel for ${BASELINE_BRANCH}:${BASELINE_COMMIT_SHA}"
+git checkout "${BASELINE_COMMIT_SHA}"
+mkdir ./tmp
+PYO3_PYTHON=python3.9 CIBW_BUILD=1 python3.9 -m pip wheel --no-deps -w ./tmp/ ./
+for wheel in ./tmp/*.whl;
+do
+  auditwheel repair "$wheel" --plat "manylinux2014_x86_64" -w ./
+done

.gitlab/scripts/get-pipelines-for-ref.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Usage:
+#   ./get-pipelines-for-ref.sh <ref>
+#
+# Example:
+#   ./get-pipelines-for-ref.sh 3dbf82a
+#
+# Environment:
+#   GITLAB_TOKEN (required)
+
+GITLAB_API_URL=${GITLAB_API_URL:-"https://gitlab.ddbuild.io/api/v4"}
+GITLAB_PROJECT_ID=${GITLAB_PROJECT_ID:-"358"}
+
+if [[ $# -ne 1 ]]; then
+  echo "usage: $0 <commit-sha-or-tag>" >&2
+  exit 1
+fi
+
+if [[ -z "${GITLAB_TOKEN:-}" ]]; then
+  echo "GITLAB_TOKEN is not set" >&2
+  exit 1
+fi
+
+REF="$1"
+
+curl --show-error --silent --fail \
+  --header "PRIVATE-TOKEN: ${GITLAB_TOKEN}" \
+  "${GITLAB_API_URL}/projects/${GITLAB_PROJECT_ID}/pipelines?sha=${REF}"