How to Build and Install an Edge App

Before you start

• At least one Controller added and online — see How to Add a Controller
• Familiarity with the bridge.* runtime — see What are Edge Apps?

Step 1 — Create the Edge App

Create a new Edge App with a handle and name. It starts as a Draft you can edit freely.

Step 2 — Declare connections and config

In the app’s manifest, declare:

• The MQTT brokers and/or OPC-UA servers it talks to, each under a server alias you’ll reference in code
• A config schema for any per-installation variables (e.g. a broker URL or a unit ID) and secrets (e.g. a password)

Broker fields can use ${config:NAME} templates so each installation can supply its own value.

Step 3 — Write the handlers

Handlers run in the bridge.* runtime (gopher-lua) — there is no ctx. A common export is onMessage. Example:

function onMessage(msg)
  -- forward an incoming reading to a local MQTT broker
  local ok, err = bridge.mqtt.publish("default", "factory/state", msg.payload, { qos = 1 })
  if not ok then
    bridge.log.warning("publish failed", { err = err })
  end

  -- remember the last value across restarts
  bridge.state.set("last", msg.payload)
  return { ok = true }
end

Use bridge.opcua.write(server, nodeId, value) / bridge.opcua.call(...) for OPC-UA, and bridge.graphql to push data into CoCoCo.

Step 4 — Publish the Draft

When the Draft is ready, Publish it. Publishing freezes the version and flips it to Published; the previously published version for the same handle is automatically deprecated.

Step 5 — Install it on a Controller

Install the published app onto a Controller:

1. Select the Controller
2. Fill in the variables and secrets defined by the config schema
3. Save

CoCoCo validates the variables against the config schema and pushes the configuration to the Controller, which starts running the app under a dedicated bot identity.

Step 6 — Verify

• Check the Controller shows the installation as active
• Invoke a handler (the app’s onMessage export) to test it end to end
• Inspect bridge.log output for errors

Managing installations

• Upgrade an installation to a newer published version (the Controller restarts with the new content)
• Deprecate a published app to retire it without breaking existing installations
• Uninstall by deleting the installation (pushes an updated config to the Controller)
• Export / Import an app as YAML or JSON to move it between environments

Related articles

• How to Add a Controller
• What are Edge Apps?