public static async Task <HttpResponseMessage> Run(
[HttpTrigger(AuthorizationLevel.Function,
"post",
Route = null)] HttpRequestMessage req,
[EventHub(
"", // Not used if the name is in the connection string
Connection = Config.EventHubConnectionStringConfigField)] ICollector <EventData> messages,
ILogger log,
ExecutionContext context)
{
using (var payload = BufferUtils.GetStream())
{
try
{
string clientId = null;
string batchId = context.InvocationId.ToString("N");
string ingestTimestamp = DateTime.UtcNow.ToString("O");
// Extract content from body
string content = await GetContentAsStringAsync(req.Content);
using (StreamWriter writer = new StreamWriter(payload, new UTF8Encoding(false, true), 4 * 1024, true))
{
// Create a JSONL formatted payload (one json structure per line)
foreach (var se in ParseContent(content))
{
clientId = clientId ?? se["client_id"].Value <string>();
// Stamp event with ingestion metadata - Useful for debugging issues later
se.Add("ingest_ts", JToken.FromObject(ingestTimestamp));
se.Add("ingest_activity_id", JToken.FromObject(batchId));
se.Add("ingest_version", INGEST_VERSION);
// Check to make sure we can generate a unique id for this event
// Cosmos DB will reject creation of a new document with an existing id
Debug.Assert(se["client_id"] != null && se["client_ts"] != null && se["seq"] != null);
// The client can also generate a unique id for it, if it wishes
se["id"] = se["id"] ?? ComputeHash(se["client_id"], se["client_ts"], se["seq"]);
// Any newlines inside of values are automatically escaped.
string result = se.ToString(Formatting.None);
writer.WriteLine(result);
log.LogTrace(result);
}
}
// Choosing optimal because the expected data size isn't huge anyway
var compressedPayload = BufferUtils.GzipCompressToArray(payload, CompressionLevel.Optimal);
if (compressedPayload.Length > MAX_EH_PAYLOAD_SIZE)
{
return(req.CreateErrorResponse(HttpStatusCode.RequestEntityTooLarge,
"The content after compression was larger than the max allowed Event Hub payload size."));
}
// Send payload on to event hub if not disabled
if (Config.EnableEventHub)
{
EventData batch = new EventData(compressedPayload);
batch.SetGzipEncoding();
batch.SetVersion(PAYLOAD_VERSION);
messages.Add(batch);
}
}
catch (Exception ex)
{
log.LogError(ex, "Ingestion failed to send telemetry to event hub.\n" + ex.StackTrace);
return(req.CreateErrorResponse(HttpStatusCode.BadRequest, "Ingestion failed to send telemetry to event hub."));
}
return(req.CreateResponse(HttpStatusCode.Accepted));
}
}
