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Example apps

Go and Redis HTTP Server

This guide explains how to create and deploy a Go app with a Redis database. To run this example, follow these steps:

1. Install the unikraft CLI. You need a BuildKit builder. The easiest way to get one is via Docker. Alternatively, you can also directly set up and use BuildKit, see the quick start.

2. Clone the examples repository and cd into the examples/httpserver-go1.22-redis directory:

   Code
   git clone https://github.com/unikraft-cloud/examples
   cd examples/httpserver-go1.22-redis/

Make sure to log into Unikraft Cloud and pick a metro close to you. This guide uses fra (Frankfurt, 🇩🇪):

Code
unikraft login

Redis

First, deploy the Redis instance. Redis is an internal service (not publicly accessible), reached via the go122-redis.internal domain. The Redis password is set at runtime via the REDIS_PASSWORD environment variable (defaults to unikraft if not provided).

Code
unikraft build ./redis --output <my-org>/httpserver-go-122-redis-db:latest
unikraft run --metro fra \
  -m 256M \
  --scale-to-zero policy=idle,cooldown-time=1000,stateful=true \
  --domain go122-redis.internal \
  -e REDIS_PASSWORD=unikraft \
  --image <my-org>/httpserver-go-122-redis-db:latest

Make sure to replace <my-org> with your username / org-name.

The output shows the Redis instance details:

Code
metro:           fra
name:            httpserver-go-122-redis-db-2xc9u
uuid:            8abe24f6-5670-4e9b-8955-8ec10f3bad21
state:           starting
image:           <my-org>/httpserver-go-122-redis-db
resources:
  memory:        256MiB
  vcpus:         1
service:
  name:          late-sound-rhboe98o
  uuid:          01953c15-8a2e-4c1a-ac24-98a9417c5aa2
  domains:
  - fqdn:        go122-redis.internal
networks:
- uuid:          e76ae319-d210-4566-ad75-baed32fc3d2b
  private-ip:    10.0.0.85
  mac:           12:b0:0a:00:00:55
timestamps:
  created:       just now
scale-to-zero:
  enabled:       true
  policy:        idle
  stateful:      true
  cooldown-time: 1s

Go HTTP Server

Next, deploy the Go HTTP server. It connects to Redis using the REDIS_ADDR and REDIS_PASS environment variables:

Code
unikraft build ./httpserver-go --output <my-org>/httpserver-go-122-redis-app:latest
unikraft run --metro fra \
  -m 256M \
  -p 443:8080/tls+http \
  --scale-to-zero policy=on,cooldown-time=1000 \
  --env REDIS_ADDR=go122-redis.internal:6379 \
  --env REDIS_PASS=unikraft \
  --image <my-org>/httpserver-go-122-redis-app:latest

The output shows the instance address and other details:

Code
metro:           fra
name:            httpserver-go-122-redis-app-bnnnc
uuid:            82093bcf-fc4c-471c-89c8-4d0b7810e280
state:           starting
image:           <my-org>/httpserver-go-122-redis-app
runtime:
  env:
    REDIS_ADDR:  go122-redis.internal:6379
    REDIS_PASS:  unikraft
resources:
  memory:        256MiB
  vcpus:         1
service:
  name:          frosty-cherry-32qs6na2
  uuid:          bcb9a2af-cfce-4731-9844-5a368696ee7d
  domains:
  - fqdn:        frosty-cherry-32qs6na2.fra.unikraft.app
networks:
- uuid:          f9030f74-4e85-445b-a57e-36ec76137c88
  private-ip:    10.0.0.173
  mac:           12:b0:0a:00:00:ad
timestamps:
  created:       just now
scale-to-zero:
  enabled:       true
  policy:        on
  cooldown-time: 1s

In this case, the instance names are httpserver-go-122-redis-db-2xc9u and httpserver-go-122-redis-app-bnnnc. They're different for each run.

To set a value in Redis via the Go server, use the URL from the fqdn field:

Code
curl -X POST -d "key=my-key" -d "value=my-value" https://<FQDN>

Code
Success!

You can then retrieve the value:

Code
curl https://<FQDN>/?key=my-key

Code
Key "my-key" has value "my-value"

You can list information about the instances by running:

Code
unikraft instances list

Code
METRO  NAME                               STATE    IMAGE                                 ARGS  MEMORY  VCPUS  FQDN                                     CREATED
fra    httpserver-go-122-redis-app-bnnnc  standby  <my-org>/httpserver-go-122-redis-app        256MiB  1      frosty-cherry-32qs6na2.fra.unikraft.app  4 minutes ago
fra    httpserver-go-122-redis-db-2xc9u   standby  <my-org>/httpserver-go-122-redis-db         256MiB  1      go122-redis.internal                     5 minutes ago

Clean up

When done, remove the instances:

Code
unikraft instances delete httpserver-go-122-redis-db-2xc9u httpserver-go-122-redis-app-bnnnc

Learn more

Use the --help option for detailed information on using Unikraft Cloud:

Code
unikraft --help

Or visit the CLI Reference.