Creating the start up script

The start up script is used to initialize the VM during a boot or a restart with the necessary software (MongoDB, Node.js, supervisor, and others) and loads the application from the source code repository. The following script can be found in the /Chapter01/ folder of the Git repository. The start up script performs the following tasks:

1. Installs the logging agent which is an application based on Fluentd.
2. Installs the MongoDB database to be used by the KeystoneJS application.
3. Installs Node.js, Git, and supervisor. Supervisor is a process control system which is used to run our KeystoneJS application as a process.
4. Clones the application code from the repository to the local folder. Update the code at #Line 60, to reflect your repository's URL:

git clone https://source.developers.google.com/p/<PROJECT ID>/r/<REPOSITORY NAME> /opt/app #Line 60

5. Installs the dependencies and creates the .env file to hold the environment variables:

COOKIE_SECRET=<Long Random String>

6. The application is configured to run under the supervisor:

#! /bin/bash 
# Source url: https://github.com/GoogleCloudPlatform/nodejs-getting-started/blob/master/7-gce/gce/startup-script.sh 
# The startup-script is modified to suit the Chapter 01-Recipe 01 of our book
#  Copyright 2017, Google, Inc. 
# Licensed under the Apache License, Version 2.0 (the "License"); 
# you may not use this file except in compliance with the License. 
# You may obtain a copy of the License at 
# 
#    http://www.apache.org/licenses/LICENSE-2.0 
# 
# Unless required by applicable law or agreed to in writing, software 
# distributed under the License is distributed on an "AS IS" BASIS, 
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
# See the License for the specific language governing permissions and 
# limitations under the License. 
 
# [START startup] 
set -v  

7. Talks to the metadata server to get the project ID:

PROJECTID=$(curl -s "http://metadata.google.internal/computeMetadata/v1/project/project-id" -H "Metadata-Flavor: Google")
# Install logging monitor. The monitor will automatically pick up logs sent to
# syslog.
# [START logging]
curl -s "https://storage.googleapis.com/signals-agents/logging/google-fluentd-install.sh" | bash
service google-fluentd restart &
# [END logging]

8. Installs MongoDB:

apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv EA312927
echo "deb http://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.2 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.2.list
apt-get update
apt-get install -y mongodb-org
cat > /etc/systemd/system/mongodb.service << EOF
[Unit]
Description=High-performance, schema-free document-oriented database
After=network.target
[Service]
User=mongodb
ExecStart=/usr/bin/mongod --quiet --config /etc/mongod.conf
[Install]
WantedBy=multi-user.target
EOF
systemctl start mongodb
systemctl enable mongodb 

9. Installs dependencies from apt:

apt-get install -yq ca-certificates git nodejs build-essential supervisor

mkdir /opt/nodejs
curl https://nodejs.org/dist/v4.2.2/node-v4.2.2-linux-x64.tar.gz | tar xvzf - -C /opt/nodejs --strip-components=1
ln -s /opt/nodejs/bin/node /usr/bin/node
ln -s /opt/nodejs/bin/npm /usr/bin/npm

11. Gets the application source code from the Google Cloud Source Repositories:

# git requires $HOME and it's not set during the startup script.
export HOME=/root
git config --global credential.helper gcloud.sh
git clone https://source.developers.google.com/p/<Project ID>/r/gcpcookbook  /opt/app

cd /opt/app/Chapter01/mysite
npm install
cat >./.env << EOF
COOKIE_SECRET=d44d5c45e7f8149aabc06a830dba5716b4bd952a639c82499954
MONGODB_URI=mongodb://localhost:27017
EOF

13. Creates a nodeapp user. The application will run as this user:

useradd -m -d /home/nodeapp nodeapp
chown -R nodeapp:nodeapp /opt/app

14. Configures the supervisor to run the nodeapp:

cat >/etc/supervisor/conf.d/node-app.conf << EOF
[program:nodeapp]
directory=/opt/app/Chapter01/mysite
command=npm start
autostart=true
autorestart=true
user=nodeapp
environment=HOME="/home/nodeapp",USER="nodeapp",NODE_ENV="production"
stdout_logfile=syslog
stderr_logfile=syslog
EOF
supervisorctl reread
supervisorctl update
# Application should now be running under supervisor
# [END startup]