Run a lambda

The run lambda command invokes an existing lambda. Lambdas run on a remote device where the On Prem Agent is running. You may provide a --device option to specify where the lambda is run.

Note that manually invoking a lambda on a device requires connectivity, and might be something you're only able to do during the factory burn-in phase of your project. In air-gapped environments, lambdas can work on high-throughput low-latency signals without any need of network connectivity.

Running on a device

graph LR;

cli --> control_plane;
control_plane <-- tunnel --> agent;
agent --> lua_vm;

subgraph user_edge[User Edge]
cli[CLI];
end

subgraph cloud[Cloud: api.on-prem.net]
control_plane[Control Plane];
end

subgraph device_edge[Device Edge]
agent[Agent];
lua_vm[Embedded Lua VM];
end

Register the lambda

# mylambda.yaml
id: abcd
name: example
description: >
  A simple example that performs a transformation on the input event.
scriptContentType: text/x-lua
script: >
  local M = {}

  function M.handler(event, context)
    local retval = event
    if event['a'] ~= nil then
      retval['d'] = event['a']+1
    end
    return retval
  end

  return M

$ onprem import lambdas mylambda.yaml

Run it

$ onprem run lambda abcd --device ci2fabp32ckvhk1g9qe0 --event '{"a":123,"b":true,"c":"dog"}'
{"a":123,"b":true,"c":"dog","d":124}