Getting started with Ruby on Compute Engine

Running the app in Cloud Shell

1. In Cloud Shell, install your app dependencies using bundle:

   bundle install
   

2. Run the Sinatra app:

   bundle exec ruby app.rb -p 8080
   

3. In Cloud Shell, click Web preview , and select Preview on port 8080. This opens a new window with your running app.

4. To stop the local web server, press Control+C.

Deploying to a single instance

This section walks you through running a single instance of your app on Compute Engine.

From Cloud Shell, you can deploy to a single Compute Engine instance virtual machine (VM) which runs your app.

Use a startup script to initialize an instance

You need a way to instruct your instance to download and run your code. An instance can have a startup script that runs whenever the instance is started or restarted.

# Install Stackdriver logging agent
curl -sSO https://dl.google.com/cloudagents/add-logging-agent-repo.sh
bash add-logging-agent-repo.sh --also-install

# Install dependencies
apt-get update && apt-get -y upgrade && apt-get install -y autoconf bison \
    build-essential git libssl-dev libyaml-dev libreadline6-dev zlib1g-dev \
    libncurses5-dev libffi-dev libgdbm3 libgdbm-dev nginx supervisor

# Account to own server process
useradd -m -d /home/rubyapp rubyapp

# Install Ruby and Bundler
mkdir /home/rubyapp/.ruby
git clone https://github.com/rbenv/ruby-build.git /home/rubyapp/.ruby-build
/home/rubyapp/.ruby-build/bin/ruby-build 2.6.5 /home/rubyapp/.ruby

chown -R rubyapp:rubyapp /home/rubyapp

cat >/home/rubyapp/.profile << EOF
export PATH="/home/rubyapp/.ruby/bin:$PATH"
EOF

su -l rubyapp -c "gem install bundler"

# Fetch source code
git clone https://github.com/GoogleCloudPlatform/getting-started-ruby.git /opt/app

# Set ownership to newly created account
chown -R rubyapp:rubyapp /opt/app

# Install ruby dependencies
su -l rubyapp -c "cd /opt/app/gce && bundle install"

# Disable the default NGINX configuration
rm /etc/nginx/sites-enabled/default

# Enable our NGINX configuration
cp /opt/app/gce/rubyapp.conf /etc/nginx/sites-available/rubyapp.conf
ln -s /etc/nginx/sites-available/rubyapp.conf /etc/nginx/sites-enabled/rubyapp.conf

# Start NGINX
systemctl restart nginx.service

# Configure supervisor to run the ruby app
cat >/etc/supervisor/conf.d/rubyapp.conf << EOF
[program:rubyapp]
directory=/opt/app/gce
command=bash -lc "bundle exec ruby app.rb"
autostart=true
autorestart=true
user=rubyapp
environment=HOME="/home/rubyapp",USER="rubyapp"
stdout_logfile=syslog
stderr_logfile=syslog
EOF

supervisorctl reread
supervisorctl update

# Application should now be running under supervisor

The startup script performs these tasks:

• Installs the Cloud Logging agent. The agent automatically collects logs from syslog.

• Installs Ruby 2.6.5, Bundler, and their system dependencies.

• Clones the app's source code from the Cloud Source Repositories and installs dependencies.

• Install and configures Nginx.

• Installs Supervisor to run the app as a daemon.

• Configures Supervisor to run the app. Supervisor makes sure the app is restarted if it exits unexpectedly or is terminated by an admin or other process. It also sends the app's stdout and stderr to syslog to be collected by the Logging agent.

Create and configure a Compute Engine instance

1. Create a Compute Engine instance:

   Linux/macOS

   MY_INSTANCE_NAME="my-app-instance"
   ZONE=us-central1-a
   
   gcloud compute instances create $MY_INSTANCE_NAME \
       --image-family=debian-9 \
       --image-project=debian-cloud \
       --machine-type=g1-small \
       --scopes userinfo-email,cloud-platform \
       --metadata-from-file startup-script=startup-script.sh \
       --zone $ZONE \
       --tags http-server

   Windows

   gcloud compute instances create my-app-instance ^
       --image-family=debian-9 ^
       --image-project=debian-cloud ^
       --machine-type=g1-small ^
       --scopes userinfo-email,cloud-platform ^
       --metadata-from-file startup-script=gce/startup-script.sh ^
       --zone us-central1-a ^
       --tags http-server
   

   Replace the zone with a development zone, for example us-central1-a. For more information on regions and zones, see Geography and regions.

   This creates a new instance, allows it to access Cloud de Confiance services, and runs your startup script. The instance name is my-app-instance.

2. Check the progress of the instance creation:

   gcloud compute instances get-serial-port-output my-app-instance --zone YOUR_ZONE
   

   Replace YOUR_ZONE with the zone you deployed your instance to.

   When the startup script is complete, you see the following message:

   startup-script: INFO Finished running startup scripts.
   

3. Create a firewall rule to allow traffic to your instance:

   gcloud compute firewall-rules create default-allow-http-80 \
       --allow tcp:80 \
       --source-ranges 0.0.0.0/0 \
       --target-tags http-server \
       --description "Allow port 80 access to http-server"
   

4. Get the external IP address of your instance:

   gcloud compute instances list
   

5. To see your app running, enter this URL in your browser:

   http://YOUR_INSTANCE_IP
   

   Replace YOUR_INSTANCE_IP with the external IP address of your instance.

Manage and monitor an instance

You can use the Cloud de Confiance console to monitor and manage your instance.

1. In the Cloud de Confiance console, go to the VM instances page.

   Go to VM instances

2. In the list of virtual machine instances, click SSH in the row of the instance that you want to connect to.

3. To view all of the logs generated by your Compute Engine resources, go to the Logs Explorer page.

   Go to Logs Explorer

   Cloud Logging is automatically configured to gather logs from various common services, including syslog.