nikogura/guestbook

Just playing around with go and databases

guestbook

A really simple implementation of your classic guestbook hello world app.

Why? I wanted to play with some database stuff in go.

I also needed a frontend/backend app to mess with as a subject for some infrastructre projects.

This isn't going to win any points, but as long as it stands up and does something, it's good enough.

Running the Code Locally

Prerequisites

• A properly set up Go SDK

• Git, and access to GitHub

• Postgres running locally on port 5432

• A Database called 'guestbook' with a user called 'guestbook' and a password 'guestbook'. Imaginative, I know

Installation

Be sure to set $GOPATH, and put $GOPATH/bin into your $PATH

Once you have one, install the guestbook app with:

    go get github.com/nikogura/guestbook

The service expects a config file at /etc/guestbook/guestbook.json. It's contents should look like:

    {
      "state": {
        "manager": {
          "type": "gorm",
    	  "dialect": "postgres",
          "connect_string": "postgresql://guestbook:guestbook@localhost:5432/guestbook?sslmode=disable"
        }
      },
      "server": {
        "addr": "0.0.0.0:8080"
      }
    }

Running

You can run the service with:

    guestbook run

You can run the snapshot tool with:

    guestbook snapshot <space separated list of instance names>

Snapshotting only works with AWS, not VirtualBox. If you call guestbook snapshot without additional arguments, it will snapshot all your running instances. Use with care.

You can get help by running:

    guestbook help

Running the Stack with Vagrant and VirtualBox

Prereqs

• VirtualBox https://www.virtualbox.org/wiki/Downloads

• Vagrant https://www.vagrantup.com/downloads.html

Run Service

From the root of this cloned repository run the following:

    cd vagrant
    
    vagrant up

Test

Point a browser at http://localhost:8080/guestbook/

Enjoy!

Running the Stack in AWS

Prereqs

• Appropriate AWS creds positioned in ~/.aws/credentials .

• Region config in ~/.aws/config. This demo architecture is hardcoded for the region us-east-1.

• Terraform. You can install manually via: Terraform Download Page Alternately, on a Mac, you can just run brew install terraform. Your choice.

• SSH keys installed in the normal location (~/.ssh/id_rsa and ~/.ssh/id_rsa.pub)

Configuration

The terraform config as writen is set to allow my ip access to the backend, not yours. You'll need to modify the file terraform/variables.tf with your IP information.

NOTE: There is a 'bug' with the external ELB config in that Terraform does not like setting an elb in multiple subnets in the same availability zone. Likewise, it doesn't like you setting availability zones and subnets at the same time. Depending on your user config, there is a chance that the front end ELB will not spring up with all the relevant availability zones enabled for the frontend servers.

If this happens, you just need to add the availability zones to the ELB via the console. There are ways to fix this, but so far I have not found one that entirely satisfies me, or works every time in every situation. This message will disappear if I find an acceptable solution

Run Service

To spin it all up, from the root of this checked out repository run Terraform thusly:

    cd terraform
    
    terraform apply

Test

The Terraform command above will output the front end ELB's url. Point a browser at that and enjoy!

NOTE: It can take a few minutes for DNS to pick up the change and activate the above url. Please be patient.