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Example apps

Imaginary

This example uses imaginary, an HTTP microservice for high-level image processing.

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/imaginary/ directory:

   Code
   git clone https://github.com/unikraft-cloud/examples
   cd examples/imaginary/

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

Code
unikraft login

When done, invoke the following command to deploy this app on Unikraft Cloud:

Code
unikraft build . --output <my-org>/imaginary:latest
unikraft run --metro fra \
  -m 512M \
  -p 443:8080/tls+http \
  --scale-to-zero policy=on,cooldown-time=1000 \
  --image <my-org>/imaginary:latest

The output shows the instance address and other details:

Code
metro:        fra
name:         imaginary-mwb4y
uuid:         8cf18bf7-2bf6-4f23-be07-f9c234c7962d
state:        starting
image:        <my-org>/imaginary
resources:
  memory:     512MiB
  vcpus:      1
service:
  uuid:       b9b7fa60-5f4f-13e5-41e9-eeea476f4398
  name:       divine-wind-1ycjvhqs
  domains:
  - fqdn:     divine-wind-1ycjvhqs.fra.unikraft.app
networks:
- uuid:       91467bd9-8d52-a378-4426-7014ca09e5d5
  private-ip: 10.0.3.3
  mac:        12:b0:e2:ed:95:49
timestamps:
  created:    just now

In this case, the instance name is imaginary-mwb4y and the address is https://divine-wind-1ycjvhqs.fra.unikraft.app. They're different for each run.

Use curl to query the Unikraft Cloud instance of Imaginary. You will get a health status of the service:

Code
curl -s https://divine-wind-1ycjvhqs.fra.unikraft.app/health | jq

Code
{
  "uptime": 414,
  "allocatedMemory": 0.19,
  "totalAllocatedMemory": 0.72,
  "goroutines": 6,
  "completedGCCycles": 13,
  "cpus": 1,
  "maxHeapUsage": 3.63,
  "heapInUse": 0.19,
  "objectsInUse": 846,
  "OSMemoryObtained": 7.73
}

To test the Imaginary instance on Unikraft Cloud use the /form endpoint. That is, open the https://divine-wind-1ycjvhqs.fra.unikraft.app/form address in the browser and use the existing forms to process an image.

To make actual use of the Imaginary instance, use the endpoints of the HTTP API. The API provides endpoints, together with parameters, for different image processing options: /crop, /resize, /flip, /convert, /watermark, /rotate, /blur etc.

You can list information about the instance by running:

Code
unikraft instances list

Code
METRO  NAME             STATE    IMAGE               ARGS  MEMORY  VCPUS  FQDN                                   CREATED
fra    imaginary-mwb4y  running  <my-org>/imaginary        512MiB  1      divine-wind-1ycjvhqs.fra.unikraft.app  2 minutes ago

When done, you can remove the instance:

Code
unikraft instances delete imaginary-mwb4y

The Imaginary Unikraft Cloud service works as is: you deploy it and then you query the endpoints of the HTTP API. You can customize the command line options used to start the service, by updating the cmd line in the Kraftfile:

Code
spec: v0.7

runtime: base-compat:latest

cmd: ["/usr/bin/imaginary", "-p", "8080"]

You can update the cmd line with command line option for Imaginary.

Learn more

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

Code
unikraft --help

Or visit the CLI Reference.