Infrastructure

---
title: Reference Architecture
---

flowchart LR
    subgraph caddy ["Caddy"]
        reverse_proxy("Reverse Proxy\n@ api.xsnippet.org")
        webserver("Webserver\n@ xsnippet.org")
    end

    letsencrypt[/"Let's Encrypt"/]
    caddy -->|"renew TLS certificates"| letsencrypt

    user(("User"))
    user -->|"HTTPS"| reverse_proxy
    user -->|"HTTPS"| webserver

    reverse_proxy -->|"proxy to"| xsnippet_api[["localhost:8080\n@ /opt/xsnippet-api/xsnippet-api"]]
    webserver -->|"serve at"| xsnippet_web[["HTML/JS/CSS\n@ /opt/xsnippet-web/"]]

    postgres[("PostgreSQL")]
    xsnippet_api --> postgres

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The project provides the Ansible playbook to deploy XSnippet service on a single node. This includes but not limited to provisioning the following components:

• XSnippet API
• XSnippet Web
• PostgreSQL
• Caddy

Some key points about the components can be found below:

• PostgreSQL stores its data on an external volume (if attached).

• XSnippet API is managed by a system level systemd service that drops privileges to xsnippet-api user on start. It communicates with PostgreSQL via unix sockets in order avoid managing passwords.

• Caddy server has been chosen to simplify TLS certs management, since it integrates with LetsEncrypt and requests and renews TLS certs automatically as the need arise.

Usage

It's as easy as running the following command:

$ ansible-playbook -i inventories/production site.yml

Please note, in order to provision a new node from scratch, the playbook is expected to be executed from a passwordless sudo user. If such user does not exist, please create one for ansible usage.