demo-app

README

demo-app

A small http UI echo server to use as a platform engineering example application. This listens with HTTP on port 8080 and can output various facts about the request and server. This is great for demonstrating:

• Deployment lifecycle
  • Update the message-of-the-day or background color, redeploy, and watch the replicas update.
• Customisation of environment variables and files in the container
  • For example, a different message-of-the-day per environment.
• Customisation of container resources
  • The detailed drop down shows the platform and number of cpus available.
• Load-balancing between replicas
  • The HTTP endpoint and readiness checks can be used as a load balancing target.
  • The HTTP page reloads itself every few seconds to continuously generate requests.
• Demonstrating a Redis and/or Mysql/Postgres connection
  • A counter is stored in Redis, and a query is performed against a database to validate the connection.

Docker image for Linux

docker pull ghcr.io/astromechza/demo-app:latest

Go binary

To install the binary into your own image or system, do the following and it should be available on $GOPATH/bin/demo-app.

go install github.com/astromechza/demo-app@latest

Options

The following flags are available and may also be set through the OVERRIDE_<flag uppercase> environment variables.

  -color string
    	the background color to display (default "random")
  -listen string
    	the address to listen on (default ":8080")
  -motd string
    	specify a message of the day, prefix with '@' to read from a file (default "Hello World")
  -postgres string
    	Optional postgres url 'postgres://<user>:<pass>@<host>:<port>/<database>'
  -mysql string
    	Optional postgres url '<user>:<pass>@tcp(<host>:<port>)/<database>'
  -proxy string
    	forward the request to the given http or https endpoint
  -redis string
    	Optional redis url 'redis://<user>:<pass>@<host>:<port>'

Running with Score

A Score file is provided in score.yaml which can be used to easily run this demo with the postgres and redis provisioned.

score-compose init
score-compose generate score.yaml --image ghcr.io/astromechza/demo-app:latest
docker compose up -d
score-compose resources get-outputs 'dns.default#example.dns' --format 'http://{{.host}}:8080'