Copy page

Example apps

C++ Boost HTTP Server

This guide explains how to create and deploy a C++-based HTTP web server using the Boost libraries. 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 example repository and cd into the examples/httpserver-boost1.74-gpp13.2/ directory:

   Code
   git clone https://github.com/unikraft-cloud/examples
   cd examples/httpserver-boost1.74-gpp13.2/

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>/httpserver-boost174-gpp132:latest
unikraft run --metro fra \
  -m 256M \
  -p 443:8080/tls+http \
  --scale-to-zero policy=on,cooldown-time=1000 \
  --image <my-org>/httpserver-boost174-gpp132:latest

The output shows the instance address and other details:

Code
metro:        fra
name:         httpserver-boost174-gpp132-rae7s
uuid:         5a9886fa-f8a3-4860-afcf-d5eb13fdc38d
state:        starting
image:        <my-org>/httpserver-boost174-gpp132
resources:
  memory:     256MiB
  vcpus:      1
service:
  uuid:       52cfb573-c035-9f0c-5db7-63615d26f182
  name:       red-snow-3bn7bzc8
  domains:
  - fqdn:     red-snow-3bn7bzc8.fra.unikraft.app
networks:
- uuid:       44a3d2c5-9ee5-fffc-b72f-d6109072bb8c
  private-ip: 10.0.6.4
  mac:        12:b0:97:bc:2c:03
timestamps:
  created:    just now

In this case, the instance name is httpserver-boost174-gpp132-rae7s and the address is https://red-snow-3bn7bzc8.fra.unikraft.app. They're different for each run.

Use curl to query the Unikraft Cloud instance of the C++ Boost HTTP web server:

Code
curl https://red-snow-3bn7bzc8.fra.unikraft.app

Code
Hello, World!

You can list information about the instance by running:

Code
unikraft instances list

Code
METRO  NAME                              STATE    IMAGE                                ARGS  MEMORY  VCPUS  FQDN                                CREATED
fra    httpserver-boost174-gpp132-rae7s  running  <my-org>/httpserver-boost174-gpp132        256MiB  1      red-snow-3bn7bzc8.fra.unikraft.app  2 minutes ago

When done, you can remove the instance:

Code
unikraft instances delete httpserver-boost174-gpp132-rae7s

Customize your app

To customize the app, update the files in the repository, listed below:

• http_server.cpp: the C++ HTTP server implementation
• Kraftfile: the Unikraft Cloud specification
• Dockerfile: the Docker-specified app filesystem

Lines in the Kraftfile have the following roles:

• spec: v0.7: The current Kraftfile specification version is 0.7.

• runtime: base: The Unikraft runtime kernel to use is its base one.

• rootfs: Build the app root filesystem. source: ./Dockerfile means the filesystem is built using the Dockerfile. format: erofs means the filesystem type is EROFS.

• cmd: ["/http_server"]: Use /http_server as the starting command of the instance.

Lines in the Dockerfile have the following roles:

• COPY ./http_server.cpp /src/http_server.cpp: Copy the server implementation file (http_server.cpp) in the Docker filesystem (in /src/http_server.cpp).

The following options are available for customizing the app:

• If you only update the implementation in the http_server.cpp source file, you don't need to make any other changes.

• If you create any new source files, copy them into the app filesystem by using the COPY command in the Dockerfile.

• More extensive changes may require extending the Dockerfile (see Dockerfile syntax reference).

Learn more

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

Code
unikraft --help

Or visit the CLI Reference.