Skip building HotROD for all platforms for pull requests (#5765)

## Which problem is this PR solving?
- Resolves #5743 

## Description of the changes
- Similar to the functionality we have for all-in-one image I tried to
achieve same build configuration supported by corresponding script file.

## Checklist
- [x] I have read
https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
- [x] I have signed all commits
- [ ] I have added unit tests for the new functionality
- [x] I have run lint and test steps successfully
  - for `jaeger`: `make lint test`
  - for `jaeger-ui`: `yarn lint` and `yarn test`

---------

Signed-off-by: Manoramsharma <[email protected]>
Signed-off-by: Yuri Shkuro <[email protected]>
Co-authored-by: Yuri Shkuro <[email protected]>

.github/workflows/ci-docker-hotrod.yml

@@ -39,13 +39,21 @@ jobs:
     - name: Export BRANCH variable
       uses: ./.github/actions/setup-branch
 
-    - name: Install tools
-      run: make install-ci
-
     - uses: docker/setup-qemu-action@5927c834f5b4fdf503fca6f4c7eccda82949e1ee # v3.1.0
 
+    - name: Define BUILD_FLAGS var if running on a Pull Request
+      run: |
+        case ${GITHUB_EVENT_NAME} in
+          pull_request)
+            echo "BUILD_FLAGS=-l -p linux/amd64" >> ${GITHUB_ENV}
+            ;;
+          *)
+            echo "BUILD_FLAGS=" >> ${GITHUB_ENV}
+            ;;
+        esac
+
     - name: Build, test, and publish hotrod image
-      run: bash scripts/hotrod-integration-test.sh
+      run: bash scripts/hotrod-integration-test.sh ${{ env.BUILD_FLAGS }}
       env:
         DOCKERHUB_TOKEN: ${{ secrets.DOCKERHUB_TOKEN }}
         QUAY_TOKEN: ${{ secrets.QUAY_TOKEN }}

scripts/hotrod-integration-test.sh

@@ -2,33 +2,60 @@
 
 set -euxf -o pipefail
 
+print_help() {
+  echo "Usage: $0 [-l] [-D] [-p platforms] [-h]"
+  echo "-h: Print help"
+  echo "-l: Enable local-only mode that only pushes images to local registry"
+  echo "-p: Comma-separated list of platforms to build for (default: all supported)"
+  exit 1
+}
+
 docker_compose_file="./examples/hotrod/docker-compose.yml"
 platforms="linux/amd64,linux/s390x,linux/ppc64le,linux/arm64"
+current_platform="$(go env GOOS)/$(go env GOARCH)"
+LOCAL_FLAG=''
+
+while getopts "lp:h" opt; do
+	case "${opt}" in
+	l)
+		# in the local-only mode the images will only be pushed to local registry
+		LOCAL_FLAG='-l'
+		;;
+	p)
+		platforms=${OPTARG}
+		;;
+	*)
+		print_help
+		;;
+	esac
+done
 
 teardown() {
   echo "Tearing down..."
   docker compose -f "$docker_compose_file" down
 }
 trap teardown EXIT
 
-make build-examples GOOS=linux GOARCH=amd64
-make build-examples GOOS=linux GOARCH=s390x
-make build-examples GOOS=linux GOARCH=ppc64le
-make build-examples GOOS=linux GOARCH=arm64
-
 make prepare-docker-buildx
 make create-baseimg
 
-# Loop through each platform (separated by commas)
+# Build hotrod binary for each target platform (separated by commas)
 for platform in $(echo "$platforms" | tr ',' ' '); do
+  # Extract the operating system from the platform string
+  os=${platform%%/*}  #remove everything after the last slash
   # Extract the architecture from the platform string
   arch=${platform##*/}  # Remove everything before the last slash
-  make "build-all-in-one" GOOS=linux GOARCH="${arch}"
+  make build-examples GOOS="${os}" GOARCH="${arch}"
 done
 
-# Build image locally (-l) for integration test
-bash scripts/build-upload-a-docker-image.sh -l -c example-hotrod -d examples/hotrod -p "${platforms}"
-bash scripts/build-upload-a-docker-image.sh -l -b -c all-in-one -d cmd/all-in-one -p "${platforms}" -t release
+# Build hotrod image locally (-l) for integration test.
+# Note: hotrod's Dockerfile is different from main binaries,
+# so we do not pass flags like -b and -t.
+bash scripts/build-upload-a-docker-image.sh -l -c example-hotrod -d examples/hotrod -p "${current_platform}"
+
+# Build all-in-one image locally (-l) for integration test
+make build-all-in-one
+bash scripts/build-upload-a-docker-image.sh -l -b -c all-in-one -d cmd/all-in-one -p "${current_platform}" -t release
 
 JAEGER_VERSION=$GITHUB_SHA REGISTRY="localhost:5000/" docker compose -f "$docker_compose_file" up -d
 
@@ -57,17 +84,16 @@ fi
 JAEGER_QUERY_URL="http://localhost:16686"
 EXPECTED_SPANS=35
 MAX_RETRIES=30
-SLEEP_INTERVAL=10
+SLEEP_INTERVAL=3
 
-# Function to poll Jaeger for the trace
 poll_jaeger() {
   local trace_id=$1
   local url="${JAEGER_QUERY_URL}/api/traces/${trace_id}"
 
   curl -s "${url}" | jq '.data[0].spans | length' || echo "0"
 }
 
-# Polling loop
+# Poll Jaeger until trace with desired number of spans is loaded or we timeout.
 span_count=0
 for ((i=1; i<=MAX_RETRIES; i++)); do
   span_count=$(poll_jaeger "${TRACE_ID}")
@@ -86,5 +112,6 @@ if [[ "$span_count" -lt "$EXPECTED_SPANS" ]]; then
   exit 1
 fi
 
-# Ensure the image is published after successful test (no -l flag)
-bash scripts/build-upload-a-docker-image.sh -c example-hotrod -d examples/hotrod -p "${platforms}"
+# Ensure the image is published after successful test (maybe with -l flag if on a pull request).
+# This is where all those multi-platform binaries we built earlier are utilized.
+bash scripts/build-upload-a-docker-image.sh ${LOCAL_FLAG} -c example-hotrod -d examples/hotrod -p "${platforms}"