For the past couple of days I have been working with Azure Functions and Event Grid.
The challenge I encountered was getting it so I could run and debug my Azure Functions locally, specifically the Even Grid Azure Function.
Finally figured it out!
For my example I am using two Azure Functions, the first is a Http Trigger function and the second is an Event Grid Trigger function.
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using System; using System.Collections.Generic; using System.IO; using System.Net.Http; using System.Text; using System.Threading.Tasks; using Microsoft.AspNetCore.Http; using Microsoft.AspNetCore.Mvc; using Microsoft.Azure.EventGrid; using Microsoft.Azure.EventGrid.Models; using Microsoft.Azure.WebJobs; using Microsoft.Azure.WebJobs.Extensions.Http; using Microsoft.Extensions.Logging; using Newtonsoft.Json; using Teamaloo.FunctionApp.Users.Data; using Teamaloo.FunctionApp.Users.Helpers; using Teamaloo.FunctionApp.Users.Models; namespace Teamaloo.FunctionApp.Users { public static class UserAddHttpTrigger { [FunctionName("AddAsync")] public static async Task<IActionResult> AddAsync( [HttpTrigger(AuthorizationLevel.Function, "post", Route = "users")] HttpRequest req, ILogger log) { var userAdd = JsonConvert.DeserializeObject<UserAdd>( await new StreamReader(req.Body).ReadToEndAsync()); if (userAdd == null) { userAdd = new UserAdd(); } if (!userAdd.IsValid) { return new BadRequestObjectResult(userAdd.ValidationResults); } var secretService = new AzureKeyVaultSecretService(); var userDataRepository = new UserDataRepository(secretService); var userData = new UserData { Name = userAdd.Name, Email = userAdd.Email }; userData = await userDataRepository.AddAsync(userData); var userAdded = new UserAdded { Id = userData.Id, Name = userData.Name, Email = userData.Email }; var topicEndpoint = await secretService.GetSecretAsync("AzureEventGridTopicEndpoint"); var topicAccessKey = await secretService.GetSecretAsync("AzureEventGridTopicAccessKey"); var events = new List<EventGridEvent>(); var eventGridEvent = new EventGridEvent(); eventGridEvent.Id = Guid.NewGuid().ToString(); eventGridEvent.Subject = $"users/{userAdded.Id}"; eventGridEvent.EventType = "UserAdded"; eventGridEvent.EventTime = DateTime.UtcNow; eventGridEvent.Data = userAdded; events.Add(eventGridEvent); var content = JsonConvert.SerializeObject(events); var client = new HttpClient(); client.DefaultRequestHeaders.Add("aeg-sas-key", topicAccessKey); var httpContent = new StringContent(content, Encoding.UTF8, "application/json"); await client.PostAsync(topicEndpoint, httpContent); return new OkObjectResult(userAdded); } } } |
This function simply adds a User to a SQL Server database.
The class AzureKeyVaultSecretService, is just a help class that extracts Environment Variables from local.settings.json, when running locally, and Azure Key Vault, when running in production.
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// Default URL for triggering event grid function in the local environment. // http://localhost:7071/runtime/webhooks/EventGrid?functionName={functionname} using Microsoft.Azure.WebJobs; using Microsoft.Azure.WebJobs.Host; using Microsoft.Azure.EventGrid.Models; using Microsoft.Azure.WebJobs.Extensions.EventGrid; using Microsoft.Extensions.Logging; using Newtonsoft.Json; namespace Teamaloo.FunctionApp.Users { public static class UserAddedEventGridTrigger { [FunctionName("UserAddedEventGridTrigger")] public static void Run([EventGridTrigger]EventGridEvent eventGridEvent, ILogger log) { log.LogInformation(JsonConvert.SerializeObject(eventGridEvent,Formatting.Indented)); } } } |
Download the Azure Grid Emulator at https://github.com/ravinsp/eventgrid-emulator. and then configure the emulator-config.json file for the Azure Grid Emulator.
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{ "port": 5000, "topics": [{ "name": "Users", "subscriptions": [{ "name": "UserAddedEventGridTrigger", "eventTypes": ["UserAdded"], "SubjectBeginsWith": "", "SubjectEndsWith": "", "endpointUrl": "http://localhost:7071/runtime/webhooks/eventgrid?functionName=UserAddedEventGridTrigger", "dispatchStrategy": "DefaultHttpStrategy" }] }], "dispatchStrategies": [{ "name": "DefaultHttpStrategy", "type": "EventGridEmulator.Logic.DispatchStrategies.DefaultHttpStrategy" }] } |
Set local.settings.json configuration.
Run your Azure Function project and the Event Grid Emulator. From Postman I make a POST call to http://localhost:7071/api/users.
Output from Azure Grid Emulator looks good! That’s it!
Related Articles
- https://docs.microsoft.com/en-us/azure/event-grid/event-schema
- https://github.com/JeremyLikness/build-event-grid/blob/master/broadcaster/Program.cs
- https://cecilphillip.com/sending-customevents-to-azureeventgrid/
- https://github.com/ravinsp/eventgrid-emulator
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Awesome! Thanks Matt.