Amazon IoT

Github Repo	C Header	C source	JS source
mongoose-os-libs/aws	mgos_aws_greengrass.h		api_aws.js

This library implements integration of Mongoose OS with AWS IoT.

See tutorial at https://mongoose-os.com/docs/mongoose-os/cloud/aws.md

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AWS GreenGrass API.

There is not much here, because GreenGrass support is almost transparent. Enable GG in the configuration aws.greengrass.enable=true and magically the global MQTT connection goes to GG instead of AWS IoT. GG core bootstrapping is done transparently by the library.

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aws_gg_net_ready

void aws_gg_net_ready(int ev, void *evd, void *arg);

Network configuration hook handler for the AWS GreenGrass.

aws_gg_reconnect

void aws_gg_reconnect(void);

Reconnect to GreenGrass.

JS API

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AWS.isConnected

AWS.isConnected()

Return value: true if AWS connection is up, false otherwise.

AWS.Shadow.setStateHandler

AWS.Shadow.setStateHandler(callback, userdata)

Set AWS shadow state handler callback.

When AWS shadow state changes, the callback is called with the following arguments: (userdata, event, reported, desired, reported_metadata, desired_metadata), where userdata is the userdata given to setStateHandler, event is one of the following: AWS.Shadow.CONNECTED, AWS.Shadow.GET_ACCEPTED, AWS.Shadow.GET_REJECTED, AWS.Shadow.UPDATE_ACCEPTED, AWS.Shadow.UPDATE_REJECTED, AWS.Shadow.UPDATE_DELTA. reported is previously reported state object (if any), and desired is the desired state (if present).

Example:

let state = { on: false, counter: 0 };  // device state: shadow metadata

// Upon startup, report current actual state, "reported"
// When cloud sends us a command to update state ("desired"), do it
AWS.Shadow.setStateHandler(function(data, event, reported, desired, reported_metadata, desired_metadata) {
  if (event === AWS.Shadow.CONNECTED) {
    AWS.Shadow.update(0, state);  // Report device state
  } else if (event === AWS.Shadow.UPDATE_DELTA) {
    for (let key in state) {
      if (desired[key] !== undefined) state[key] = desired[key];
    }
    AWS.Shadow.update(0, state);  // Report device state
  }
  print(JSON.stringify(reported), JSON.stringify(desired));
}, null);

AWS.Shadow.get

AWS.Shadow.get()

Request shadow state. The event handler (see AWS.Shadow.setStateHandler()) will receive a GET_ACCEPTED event. Returns true in case of success, false otherwise.

AWS.Shadow.getVersion

AWS.Shadow.getVersion();

Return last shadow state version (a number).

AWS.Shadow.update

AWS.Shadow.update(version, state);

Update AWS shadow state.

State should be an object with "reported" and/or "desired" keys.

Response will arrive via UPDATE_ACCEPTED or UPDATE_REJECTED events. If you want the update to be aplied only if a particular version is current, specify the version. Otherwise set it to 0 to apply to any version.

Example:

// On a button press, update press counter via the shadow
let buttonPin = 0;
GPIO.set_button_handler(buttonPin, GPIO.PULL_UP, GPIO.INT_EDGE_NEG, 200, function() {
  AWS.Shadow.update(0, {desired: {on: state.on, counter: state.counter + 1}});
}, null);

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