public async void Run([CosmosDBTrigger(
databaseName: "Tasks",
collectionName: "TaskItem",
ConnectionStringSetting = "CosmosDBConnection",
LeaseCollectionName = "leases",
CreateLeaseCollectionIfNotExists = true)] IReadOnlyList <Document> input,
//CosmosNote - For V2 SDK, we can use the cosmos binding to get a handle to the DocumentClient object. This is different than
//V3 SDK where we use dependency injection to get the handle and abstract it from the function.
[CosmosDB(
databaseName: "Tasks",
collectionName: "TaskViews",
ConnectionStringSetting = "CosmosDBConnection")] DocumentClient _cosmosClient,
ExecutionContext context,
ILogger log)
{
//CosmosNote - in our v2 code example, we get the DocumentClient from the binding. Thus, we instantiate
//the CosmosHelper here and pass in the handle to the client. In the v3 example, the CosmosClient is
//created when the singleton object is instantiated in Startup.cs.
CosmosHelper cosmosHelper = new CosmosHelper(_cosmosClient);
//Loop through all the v2 Documents we receive in the change feed.
if (input != null && input.Count > 0)
{
log.LogInformation("Documents modified " + input.Count);
foreach (Document document in input)
{
//Convert the document into a dynamic object so we can work with it without binding to a model.
dynamic task = JsonConvert.DeserializeObject <ExpandoObject>(document.ToString(), new ExpandoObjectConverter());
//Get the TaskItemView for this submitter and update it accordingly. If there is an etag discrepancy, we'll get a false back and need to try again.
bool taskOwnerViewResult = false;
while (taskOwnerViewResult == false)
{
dynamic taskOwnerView = await getTaskView(cosmosHelper, task.submittedby, log);
handleTaskApprovals(task, taskOwnerView, log);
taskOwnerViewResult = await saveTaskView(cosmosHelper, taskOwnerView, log);
}
//Loop through all the approvers in the document and update them. If there is an etag discrepancy, we'll get a false back and need to try again.
foreach (dynamic approver in task.approvers)
{
bool taskApproverResult = false;
while (taskApproverResult == false)
{
dynamic taskApproverView = await getTaskView(cosmosHelper, approver.id, log);
handleTaskApprovals(task, taskApproverView, log);
taskApproverResult = await saveTaskView(cosmosHelper, taskApproverView, log);
}
}
}
}
}
private async System.Threading.Tasks.Task <bool> saveTaskView(CosmosHelper _cosmosHelper, dynamic taskView, ILogger log)
{
//If they still have tasks to approve, go ahead and upsert the document. Otherwise, delete it for good housekeeping.
if ((taskView.mytasks.Count > 0) || (taskView.approvaltasks.Count > 0))
{
return(await _cosmosHelper.UpsertItemAsync("Tasks", "TaskViews", taskView, true, log));
}
else
{
return(await _cosmosHelper.DeleteItemAsync("Tasks", "TaskViews", taskView, true, log));
}
}
public override void Configure(IFunctionsHostBuilder builder)
{
// Register the CosmosHelper as a Singleton
builder.Services.AddSingleton((s) => {
string connectionString = configuration["CosmosDBConnection"];
if (string.IsNullOrEmpty(connectionString))
{
throw new ArgumentNullException("Please specify a valid CosmosDBConnection in the appSettings.json file or your Azure Functions Settings.");
}
CosmosHelper cosmosHelper = new CosmosHelper(connectionString);
return(cosmosHelper);
});
}
private async Task <dynamic> getTaskView(CosmosHelper _cosmosHelper, dynamic id, ILogger log)
{
dynamic taskView = null;
//Use the CosmosHelper to get the TaskView.
dynamic document = await _cosmosHelper.ReadItemAsync("Tasks", "TaskViews", id, log);
if (document != null)
{
taskView = JsonConvert.DeserializeObject <ExpandoObject>(document.ToString(), new ExpandoObjectConverter());
}
else
{
log.LogInformation($"User {id} does not have a TaskItemView. A new document will be created.");
taskView = new ExpandoObject();
taskView.id = id;
taskView.mytasks = new List <ExpandoObject>();
taskView.approvaltasks = new List <ExpandoObject>();
}
return(taskView);
}
//CosmosNote - In order to easily get the CosmosHelper to read and update Tasks, we use dependency injection. This is different from V2 where we can use
//the Cosmos function binding to get the DocumentClient, and then build the CosmosHelper.
public TaskUpdateChangeFeedFunction(CosmosHelper cosmosHelper)
{
//Get the cosmos client object that our Startup.cs creates through dependency injection.
_cosmosHelper = cosmosHelper;
}
//CosmosNote - In order to easily get the CosmosHelper to read and update Tasks, we use dependency injection. This is different from V2 where we can use
//the Cosmos function binding to get the DocumentClient, and then build the CosmosHelper.
public GetTaskViewFunction(CosmosHelper cosmosHelper)
{
//Get the cosmos client object that our Startup.cs creates through dependency injection.
_cosmosHelper = cosmosHelper;
}
