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Unipi - serve git repository content as HTTPS

Unipi is a MirageOS unikernel that provides the contents of a git repository via HTTP and HTTPS. It embeds (optional) let's encrypt provisioning.

A webhook is provided to update the internal state of the git repository. An example deployment is robur.coop, which serves the robur website (using the pages branch).

Some HTTP headers are added: "content-type", which value is looked up of the file ending using magic-mime. "last-modified" and "etag" are the timestamp of the most recent commit to the git remore, respective the hash of the most recent commit. If the client sends "if-modified-since" or "if-none-match", and either matches the most recent commit, the HTTP status Not modified (304) is returned with an empty body.

Inspiration for this unikernel is taken from Canopy after discussion with the Muen developers.

Configuration

Unipi is only configured via boot parameters, as follows:

• --port configures the TCP port to listen on (defaults to 80)
• --remote configures the git remote url (e.g. https://github.com/mirage/ocaml-dns.git#gh-pages)
• --hook configures the (secret) url of the webhook, if requested unipi updates its internal git remote (default is "hook")
• --ipv4 configures the IPv4 address of unipi (e.g. 192.168.2.2/24)
• --ipv4-gateway configures the IPv4 gateway

To use git via ssh (only public/private key authentication is supported):

• --ssh-key for the ssh private key - either rsa:<seed> or ed25519:<b64-encoded private key> (you can use the tool awa_gen_key to produce a random seed and public key)
• --ssh-authenticator to authenticate the ssh remote (format is SHA256:b64-encoded-public-key hash, the output of ssh-keygen -lf <(ssh-keyscan -t rsa|ed25519 remote-host 2>/dev/null))

For HTTPS service with let's encrypt certificate:

• --tls=true enables tls
• --hostname=my-server.example.com configuring the server name
• --production=true for let's encrypt production environment (default is false, which uses the let's encrypt staging environment)
• (optional) --cert-seed=<my-seed> seed for the private key of the certificate (dd if=/dev/random bs=32 count=1 | b64encode -m -)
• (optional) --account-seed=<my-seed> seed for the let's encrypt account (see above how to generate this)
• (optional) --email=<account email> email address used for let's encrypt account registration

For a complete list of boot parameters, execute the binary with --help as argument.

Installation from source

To install this unikernel from source, you need to have opam (>= 2.1.0) and ocaml (>= 4.08.0) installed. Also, mirage is required (>= 4.5.0). Please follow the installation instructions.

The following steps will clone this git repository and compile the unikernel:

$ git clone https://github.com/robur-coop/unipi.git
$ cd unipi
$ mirage configure -t <your-favourite-target> #i.e. hvt, spt, xen
$ make depend
$ make build

Installing as binary

Binaries are available at Reproducible OPAM builds, see Deploying binary MirageOS unikernels and Reproducible MirageOS unikernel builds for details.

Questions?

Please open an issue if you have questions, feature requests, or comments.