Wasmcloud sysext

This sysext ships wasmcloud.

The sysext includes a service unit file to start the wasmcloud and nats services at boot. Basic customisation options are discussed in the “Usage” section below.

Usage

Download and merge the sysext at provisioning time using the below butane snippet.

The snippet includes automated updates via systemd-sysupdate. Sysupdate will merge the new sysext immediately after successful download. You can deactivate updates by changing enabled: true to enabled: false in systemd-sysupdate.timer.

Note that the snippet is for the x86-64 version of wasmcloud 1.2.1.

The following customisations have been made (see comments in the config snippet)

1. Provide a different configuration to setup the nats-server to act as a leaf node to a pre-existing wasmCloud deployment (/etc/nats-server.conf).
2. Provide a set of credentials for the nats-server leaf node to connect with (/etc/nats.creds).
3. Override the bundled NATS_CONFIG environment variable to point it to the newly created configuration (NATS_CONFIG=/etc/nats-server.conf).
4. Override the lattice the wasmCloud host is configured to connect (WASMCLOUD_LATTICE=<redacted>).

variant: flatcar
version: 1.0.0

storage:
  links:
    - target: /opt/extensions/wasmcloud/wasmcloud-1.2.1-x86-64.raw
      path: /etc/extensions/wasmcloud.raw
      hard: false
  files:
    - path: /opt/extensions/wasmcloud/wasmcloud-1.2.1-x86-64.raw
      contents:
        source: https://github.com/flatcar/sysext-bakery/releases/download/latest/wasmcloud-1.2.1-x86-64.raw
    - path: /etc/sysupdate.wasmcloud.d/wasmcloud.conf
      contents:
        source: https://github.com/flatcar/sysext-bakery/releases/download/latest/wasmcloud.conf
    - path: /etc/sysupdate.d/noop.conf
      contents:
      source: https://github.com/flatcar/sysext-bakery/releases/download/latest/noop.conf
  #
  # Custom WasmCloud Config
  #
  files:
    - path: /etc/nats-server.conf
      # NATS server leaf node config
      contents:
        inline: |
          jetstream {
            domain: default
          }
          leafnodes {
              remotes = [
                  {
                      url: "tls://connect.cosmonic.sh"
                      credentials: "/etc/nats.creds"
                  }
              ]
          }
    - path: /etc/nats.creds
      # NATS server cretentials. TODO: actually add the credentials.
      contents:
        inline: |
          <redacted>
systemd:
  units:
    - name: systemd-sysupdate.timer
      enabled: true
    - name: systemd-sysupdate.service
      dropins:
        - name: wasmcloud.conf
          contents: |
            [Service]
            ExecStartPre=/usr/bin/sh -c "readlink --canonicalize /etc/extensions/wasmcloud.raw > /tmp/wasmcloud"
            ExecStartPre=/usr/lib/systemd/systemd-sysupdate -C wasmcloud update
            ExecStartPost=/usr/bin/sh -c "readlink --canonicalize /etc/extensions/wasmcloud.raw > /tmp/wasmcloud-new"
            ExecStartPost=/usr/bin/sh -c "if ! cmp --silent /tmp/wasmcloud /tmp/wasmcloud-new; then systemd-sysext refresh; fi"

    #
    # Custom WasmCloud Config
    #
    - name: nats.service
      enabled: true
      dropins:
        - name: 10-nats-env-override.conf
          contents: |
            [Service]
            Environment=NATS_CONFIG=/etc/nats-server.conf
    - name: wasmcloud.service
      # Wasmcloud env override. TODO: add lattice.
      enabled: true
      dropins:
        - name: 10-wasmcloud-env-override.conf
          contents: |
            [Service]
            Environment=WASMCLOUD_LATTICE=<redacted>