Add a wrapper for docker that waits for daemon

See linked gitlab issue for more info:
https://gitlab.com/gitlab-org/gitlab-runner/-/issues/27300

Dockerfile

@@ -73,6 +73,11 @@ ENV DOCKER_CLI_EXPERIMENTAL=enabled
 
 WORKDIR /app
 
+# Add a wrapper for docker that waits for docker daemon. See:
+# https://gitlab.com/gitlab-org/gitlab-runner/-/issues/27300
+COPY ./utils/docker-wrapper.sh /usr/local/bin/docker
+RUN chmod a+x /usr/local/bin/docker
+
 RUN apk add --no-cache \
         apache2-utils \
         bash \

utils/docker-wrapper.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+
+# A wrapper for docker to check that wait for docker daemon to spin up. See:
+# https://gitlab.com/gitlab-org/gitlab-runner/-/issues/27300
+
+wait_for_dockerd() {
+    END=$(expr $(date +%s) + 30)  # Wait for 30s at most.
+    while ! /usr/bin/docker info >/dev/null 2>&1; do
+        if [ $(date +%s) -ge "$END" ]; then
+            return 1
+        fi
+        sleep 1
+    done
+}
+
+if ! wait_for_dockerd; then
+    echo "Failed to connect Docker daemon!" >&2
+    exit 1
+fi
+
+exec /usr/bin/docker "$@"