fix: 🔧 Add Podman support to srtool runtime build script (#222)

## Summary

- Adds support for both Docker and Podman container engines in
`build-runtime-srtool.sh` via `IS_PODMAN` environment variable
- Uses `--userns=keep-id` for Podman (proper user namespace handling)
and `--user $(id -u):$(id -g)` for Docker
- Sets `IS_PODMAN=true` in `task-publish-runtime.yml` workflow to enable
Podman by default

## Changes

**`operator/scripts/build-runtime-srtool.sh`:**
- Added conditional logic to detect `IS_PODMAN` env var
- Dynamically selects between `podman` and `docker` as container engine
- Sets appropriate user/namespace flags based on container engine

**`.github/workflows/task-publish-runtime.yml`:**
- Added `IS_PODMAN: true` environment variable to the srtool build step
- Updated comment to use generic "container user" instead of "docker
user"

Co-authored-by: Claude <noreply@anthropic.com>

.github/workflows/task-publish-runtime.yml

@@ -81,8 +81,9 @@ jobs:
           GH_WORKFLOW_MATRIX_SRTOOL_IMAGE_TAG: ${{ matrix.srtool_image_tag }}
           RUNTIME_BUILD_OPTS: "--features=on-chain-release-build"
           RUNTIME_BUILD_PROFILE: "production"
+          IS_PODMAN: true
         run: |
-          # Ensure we have permissions to write to the runtime folder target for the docker user
+          # Ensure we have permissions to write to the runtime folder target for the container user
           mkdir -p operator/runtime/${GH_WORKFLOW_MATRIX_CHAIN}/target
           chmod uog+rwX operator/runtime/${GH_WORKFLOW_MATRIX_CHAIN}/target
 

operator/scripts/build-runtime-srtool.sh

@@ -6,11 +6,20 @@
 # self-hosted runner uses user `maintenance` to match srtool `builder` user 1001
 # $(~/srtool/uid-gid-mapping.sh 1001 | xargs) is used to map the user and group
 
-# Docker command to generate JSON blob of the runtime
-CMD="docker run \
+# Determine whether to use Podman or Docker
+if [ "${IS_PODMAN}" = "true" ]; then
+  CONTAINER_ENGINE="podman"
+  USER_FLAG="--userns=keep-id"
+else
+  CONTAINER_ENGINE="docker"
+  USER_FLAG="--user $(id -u):$(id -g)"
+fi
+
+# Container command to generate JSON blob of the runtime
+CMD="${CONTAINER_ENGINE} run \
   -i \
   --rm \
-  --user $(id -u):$(id -g) \
+  ${USER_FLAG} \
   -e CARGO_NET_GIT_FETCH_WITH_CLI=true \
   -e PACKAGE=datahaven-${GH_WORKFLOW_MATRIX_CHAIN}-runtime \
   -e RUNTIME_DIR=operator/runtime/${GH_WORKFLOW_MATRIX_CHAIN} \