Google Cloud Run inaccessible even on successful build - google-cloud-platform

Question

My Google Cloud Run image was build successfully using Cloud Build via Github repo. I don't see anything concerning in the build logs.
This is my Dockerfile:
# Use the official lightweight Node.js 10 image.
# https://hub.docker.com/_/node
FROM node:17-slim
RUN set -ex; \
apt-get -y update; \
apt-get -y install ghostscript; \
apt-get -y install pngquant; \
rm -rf /var/lib/apt/lists/*
# Create and change to the app directory.
WORKDIR /usr/src/app
# Copy application dependency manifests to the container image.
# A wildcard is used to ensure both package.json AND package-lock.json are copied.
# Copying this separately prevents re-running npm install on every code change.
COPY package*.json ./
# Install dependencies.
# If you add a package-lock.json speed your build by switching to 'npm ci'.
RUN npm ci --only=production
# RUN npm install --production
# Copy local code to the container image.
COPY . ./
# Run the web service on container startup.
CMD [ "npm", "start" ]
But when I try to access the cloud through the public URL I see:
Oops, something went wrong…
Continuous deployment has been set up, but your repository has failed to build and deploy.
This revision is a placeholder until your code successfully builds and deploys to the Cloud Run service myapi in asia-east1 of the GCP project myproject.
What's next?
From the Cloud Run service page, click "Build History".
Examine your build logs to understand why it failed.
Fix the issue in your code or Dockerfile (if any).
Commit and push the change to your repository.
It appears that the node app did not run. What am I doing wrong?

Answer 1

Turns out that cloudbuild.yaml is not really optional. Adding the file with the following resolved the issue:
steps:
# Build the container image
- name: "gcr.io/cloud-builders/docker"
args: ["build", "-t", "gcr.io/$PROJECT_ID/myapi:$COMMIT_SHA", "."]
# Push the container image to Container Registry
- name: "gcr.io/cloud-builders/docker"
args: ["push", "gcr.io/$PROJECT_ID/myapi:$COMMIT_SHA"]
# Deploy container image to Cloud Run
- name: "gcr.io/google.com/cloudsdktool/cloud-sdk"
entrypoint: gcloud
args:
- "run"
- "deploy"
- "myapi"
- "--image"
- "gcr.io/$PROJECT_ID/myapi:$COMMIT_SHA"
- "--region"
- "asia-east1"
images:
- "gcr.io/$PROJECT_ID/myapi:$COMMIT_SHA"