I am currently doing a POC where I would like to know if this is possible using Azure Services. I get certain data from Iot hub in my Event hub which triggers a logic app, and based on the message received from Event hub, My logic app would send a message to IoT Edge device. i would like to know if it is possible to send message to IoT hub device from logic app? and if yes how can we do that?
I am more looking Yes or No answer to my question and If I get the services to be used to achieve this.. It will be great
Yes, this is possible. Logic Apps have an Event Hub connector that you can use to start your app when a message comes in.
To send a message to your Azure IoT Edge device from a logic app, you could use the REST API. It allows you to send a direct method to a specific module on the device. The device needs to be online for it to receive the message, otherwise, the REST call will result in an error.
The challenge is that you will need to get a valid security token to complete this call, you could certainly add this to your app as a variable, but you shouldn't. You also run the risk of exposing this secret value in your run history. You could write an Azure Function to generate this security token and retrieve it with the Logic App. At this point you're writing code anyway, the problem you're trying to solve with a Logic App would be a better fit for an Azure Function.
Related
I am able to register a device on Cumulocity IoT and send measurements from the device to Cumuloicty via MQTT. Now I want to send measurement from Cumulocity to that registered device using MQTT. How can I achieve this ?
I tried going through all the documents available on cumulocity but its not mentioned clearly in those docs how we can achieve this flow. I tried the control tab in device which lets us send some single and bulk operations but did not get to a solution.
All communication from Cumulocity IoT to devices is technically covered through operations. Even if maybe in your case the content of the operation is a measurement value, set point or something like this.
The structure of the operation doesn't matter for Cumulocity IoT. Your device in the end needs to understand it.
If you have for example a case where device A sends a measurement (to Cumulocity IoT) and you want device B to receive this measurement you will need to create an operation for device B out of the measurement of device A.
This can be quite easily achieved utilizing the built-in streaming analytics in Cumulocity IoT (see https://cumulocity.com/guides/apama/overview-analytics/). Fastest approach would be the Analytics Builder.
I have a working monolith application (deployed in a container), for which I want to add notifications feature as a separate microservice.
I'm planning for the monolith to emit events to a message bus (RabbitMQ) where they will be received by the new service, which will send the notification to user. In order to compose a notification, it will need other information about the user from the monolit, so it will call monolith's REST API in order to obtain it.
The problem is, that access to the monolith's API requires authentication in form of a token. I was thinking of:
using the secret from the monolith to issue a never-expiring token - I don't think this is a great idea from the security perspective, and also I know that sometimes the keys rotate in which case the token would became invalid eventually anyway
using the message bus to retrieve the information - this does not seem a good idea either as the asynchrony would make it very complicated
providing all the info the notification service needs in the event - this would make them more coupled together, and moreover, I plan to also send notifications based on the state on the monolith not triggered by an event
removing the authentication from the monolith and implementing it differently (not sure how yet)
My question is, what are some of the good ways this kind of problem can be solved, and also, having just started learning about microservices, is what I am trying to do right in the first place?
When dealing with internal security you should always consider the deployment and how the APIs are exposed to the outside world, an API gateway might be used to simply make it impossible to access internal APIs. In that case, a fixed token might be good enough to ensure that the client is authorized.
In general, though, I would suggest looking into OAuth2 or a JWT-based solution as it helps to validate the identities of the calling system as well as their access grants.
As for your architecture doubts, you need to consider the following scenarios when building out the solution:
The remote call can fail, at any time for unknown reasons, as such you shouldn't acknowledge the notification event until you're certain that the notification has been processed successfully.
As you've mentioned RabbitMQ, you should aim to keep the notification queue as small as possible, to that effect, a cache that contains the user details might help speed things along (and help you reduce the chance of failure due to the external system not being available).
If your application sends a lot of notifications to potentially millions of different users, you could consider having a read-only database replica of the users which is accessible to the notification service, and directly read from the database cluster in batches. This reduces the load on the monolith and shift it to the database layer
I'm trying to wrap my head around how to subscribe to events in the new Sonos API for an iOS app.
It seems like a cloud service is needed to receive events from the Sonos Cloud.
As described here:
[Subscribing to events with Sonos API
[https://developer.sonos.com/build/direct-control/connect]
Is there any way for an iOS app to subscribe to events (volume and grouping change) without having to run a cloud service?
If not, any features based on event subscriptions will not be able to work if there is trouble connecting to the cloud for whatever reason.
No, there's no way to run without a cloud service. You must have a reliable cloud service for events and subscriptions.
Each device also has a super fast / local / undocumented, UPNP service that also supports events.
this answer should give you some pointers on how to get it working in node.
In a nutshell:
Setup an http endpoint on the device (not sure how that works in Swift)
Tell (in node) the speaker to start sending events for a specific service
Handle the received XML events.
Sample event from RenderingControlService (yes it has nested encoded xml in the <LastChange> property):
<e:propertyset xmlns:e="urn:schemas-upnp-org:event-1-0"><e:property><LastChange><Event xmlns="urn:schemas-upnp-org:metadata-1-0/RCS/"><InstanceID val="0"><Volume channel="Master" val="15"/><Volume channel="LF" val="100"/><Volume channel="RF" val="100"/><Mute channel="Master" val="0"/><Mute channel="LF" val="0"/><Mute channel="RF" val="0"/><Bass val="0"/><Treble val="0"/><Loudness channel="Master" val="1"/><OutputFixed val="0"/><HeadphoneConnected val="0"/><SpeakerSize val="3"/><SubGain val="0"/><SubCrossover val="0"/><SubPolarity val="0"/><SubEnabled val="1"/><SonarEnabled val="1"/><SonarCalibrationAvailable val="1"/><PresetNameList val="FactoryDefaults"/></InstanceID></Event></LastChange></e:property></e:propertyset>
Looking through the apis for DeviceClient, ServiceClient, and RegistryManager it doesn't look like there is any obvious way to get an event/callback when the reported properties for a device have changed. Therefore it seems like something consuming the IoTHub information wouldn't have any idea properties have changed without constantly polling. That seems rather inefficient and error prone. What am I missing?
The device twins has built-in an event driven notification model when the changes on the tags and properties are published via the Azure IoT Hub Routes path to the custom endpoints. See more details here.
The following screen snippet shows an example of the Azure IoT Hub Routes for TwinChangeEvents notifications:
I have a requirment to use Android C2DM functionality.
However, the restriction is that there should be no data that goes outside organization network.
Does the server side implementation send data to Google servers?
Is there an option to implement C2DM service within a closed network, where the data is not sent to Google servers?
Thanks,
RR
The purpose of C2DM is that you "Notify" the device that new data is available, and then your application is starting a sync (or something else, eg showing a message).
In general you don't submit the data (sometimes called payload) using C2DM. It is limited to 1024 chars only.
This way no "company" data is sent to Google.