Triggers and Bindings Overview¶

This page is a practical catalog of Azure Functions Python v2 triggers and bindings, including decorator names, common parameters, connection rules, and minimal code examples.

Trigger catalog (Python v2)¶

The table below covers the trigger types commonly available in Azure Functions runtime v4 with Python v2.

Trigger type	v2 decorator	Common parameters	Typical payload
HTTP Trigger	`@app.route(...)`	`route`, `methods`, `auth_level`	`func.HttpRequest`
Timer Trigger	`@app.timer_trigger(...)`	`schedule`, `arg_name`, `run_on_startup`, `use_monitor`	`func.TimerRequest`
Queue Storage Trigger	`@app.queue_trigger(...)`	`arg_name`, `queue_name`, `connection`	`func.QueueMessage` or `str`
Blob Trigger	`@app.blob_trigger(...)`	`arg_name`, `path`, `connection`, `source`	bytes/stream/blob content
Event Hub Trigger	`@app.event_hub_message_trigger(...)`	`arg_name`, `event_hub_name`, `connection`, `consumer_group`	Event Hub event batch
Service Bus Queue Trigger	`@app.service_bus_queue_trigger(...)`	`arg_name`, `queue_name`, `connection`, `is_sessions_enabled`	Service Bus message
Service Bus Topic Trigger	`@app.service_bus_topic_trigger(...)`	`arg_name`, `topic_name`, `subscription_name`, `connection`	Service Bus message
Cosmos DB Trigger	`@app.cosmos_db_trigger(...)`	`arg_name`, `database_name`, `container_name`, `connection`, `lease_container_name`	changed docs list
Event Grid Trigger	`@app.event_grid_trigger(...)`	`arg_name`	`func.EventGridEvent`
Warmup Trigger	`@app.warm_up_trigger(...)`	`arg_name`	warmup context
Durable Orchestrator Trigger	`@bp.orchestration_trigger(...)`	`context_name`	orchestration context
Durable Activity Trigger	`@bp.activity_trigger(...)`	`input_name`	activity input object
Durable Entity Trigger	`@bp.entity_trigger(...)`	`context_name`	durable entity context

Binding catalog (Input and Output)¶

Bindings connect your function to Azure services without requiring full SDK plumbing in every handler.

Binding kind	Direction	v2 decorator	Core parameters	Notes
HTTP response	Output	return value / `func.HttpResponse`	N/A	Implicit for HTTP-triggered functions
Queue Storage	Input	`@app.queue_input(...)`	`arg_name`, `queue_name`, `connection`	Read auxiliary messages
Queue Storage	Output	`@app.queue_output(...)`	`arg_name`, `queue_name`, `connection`	Emit async work items
Blob Storage	Input	`@app.blob_input(...)`	`arg_name`, `path`, `connection`	Read file/blob content
Blob Storage	Output	`@app.blob_output(...)`	`arg_name`, `path`, `connection`	Write transformed files
Event Hub	Output	`@app.event_hub_output(...)`	`arg_name`, `event_hub_name`, `connection`	Publish stream events
Service Bus	Output	`@app.service_bus_queue_output(...)`	`arg_name`, `queue_name`, `connection`	Send queue messages
Service Bus	Output	`@app.service_bus_topic_output(...)`	`arg_name`, `topic_name`, `connection`	Publish topic events
Cosmos DB	Input	`@app.cosmos_db_input(...)`	`arg_name`, `database_name`, `container_name`, `connection`	Read docs by query or id
Cosmos DB	Output	`@app.cosmos_db_output(...)`	`arg_name`, `database_name`, `container_name`, `connection`	Persist documents
Event Grid	Output	`@app.event_grid_output(...)`	`arg_name`, `topic_endpoint_uri`, `topic_key_setting`	Publish Event Grid events
Durable client	Input	`@bp.durable_client_input(...)`	`client_name`	Start/query orchestrations

Connection settings model¶

Basic app-setting connection¶

Most decorators reference connection="NAME".

For classic connection strings, NAME maps directly to an app setting.
Example: connection="AzureWebJobsStorage" reads AzureWebJobsStorage=<connection-string>.

Identity-based connection¶

For managed identity, NAME is a prefix with service-specific suffix settings.

Queue/Blob/Table Storage use URI suffix settings such as NAME__queueServiceUri.
Service Bus uses NAME__fullyQualifiedNamespace.
Event Hubs uses NAME__fullyQualifiedNamespace.
Cosmos DB commonly uses NAME__accountEndpoint.

Details and role mappings are documented in Identity-Based Connections.

Trigger examples¶

Each sample is intentionally short and focuses on decorator shape.

1) HTTP Trigger¶

import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="http_ping")
@app.route(route="ping", methods=["GET"])
def http_ping(req: func.HttpRequest) -> func.HttpResponse:
    return func.HttpResponse("pong")

2) Timer Trigger¶

import logging
import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="hourly_job")
@app.timer_trigger(schedule="0 0 * * * *", arg_name="timer")
def hourly_job(timer: func.TimerRequest) -> None:
    logging.info("hourly timer fired")

3) Queue Storage Trigger¶

import logging
import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="queue_consumer")
@app.queue_trigger(arg_name="msg", queue_name="orders", connection="StorageConn")
def queue_consumer(msg: func.QueueMessage) -> None:
    logging.info("message=%s", msg.get_body().decode("utf-8"))

4) Blob Trigger¶

import logging
import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="blob_ingest")
@app.blob_trigger(arg_name="blob", path="incoming/{name}", connection="StorageConn")
def blob_ingest(blob: bytes) -> None:
    logging.info("blob length=%d", len(blob))

5) Event Hub Trigger¶

import logging
import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="hub_consumer")
@app.event_hub_message_trigger(
    arg_name="events",
    event_hub_name="telemetry",
    connection="EventHubConn",
)
def hub_consumer(events) -> None:
    logging.info("event batch size=%d", len(events))

6) Service Bus Queue Trigger¶

import logging
import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="sb_queue_worker")
@app.service_bus_queue_trigger(
    arg_name="msg",
    queue_name="jobs",
    connection="ServiceBusConn",
)
def sb_queue_worker(msg) -> None:
    logging.info("processed service bus queue message")

7) Service Bus Topic Trigger¶

import logging
import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="sb_topic_worker")
@app.service_bus_topic_trigger(
    arg_name="msg",
    topic_name="events",
    subscription_name="functions-sub",
    connection="ServiceBusConn",
)
def sb_topic_worker(msg) -> None:
    logging.info("processed service bus topic message")

8) Cosmos DB Trigger¶

import logging
import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="cosmos_changes")
@app.cosmos_db_trigger(
    arg_name="documents",
    database_name="appdb",
    container_name="orders",
    lease_container_name="leases",
    connection="CosmosConn",
)
def cosmos_changes(documents: list) -> None:
    logging.info("changed docs=%d", len(documents))

9) Event Grid Trigger¶

import logging
import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="grid_listener")
@app.event_grid_trigger(arg_name="event")
def grid_listener(event: func.EventGridEvent) -> None:
    logging.info("event type=%s", event.event_type)

10) Warmup Trigger¶

import logging
import azure.functions as func

app = func.FunctionApp()

@app.function_name(name="warmup")
@app.warm_up_trigger(arg_name="context")
def warmup(context) -> None:
    logging.info("instance warmup invoked")

11) Durable Orchestrator Trigger¶

import azure.durable_functions as df

bp = df.Blueprint()

@bp.orchestration_trigger(context_name="context")
def order_orchestrator(context: df.DurableOrchestrationContext):
    result = yield context.call_activity("validate_order", context.get_input())
    return result

12) Durable Activity Trigger¶

import azure.durable_functions as df

bp = df.Blueprint()

@bp.activity_trigger(input_name="order")
def validate_order(order: dict) -> dict:
    return {"valid": True, "id": order.get("id")}

13) Durable Entity Trigger¶

import azure.durable_functions as df

bp = df.Blueprint()

@bp.entity_trigger(context_name="context")
def counter_entity(context: df.DurableEntityContext):
    current = context.get_state(lambda: 0)
    if context.operation_name == "add":
        context.set_state(current + context.get_input())
    elif context.operation_name == "get":
        context.set_result(current)

Rules of thumb for choosing triggers¶

Use HTTP for request/response APIs and webhooks.
Use Queue or Service Bus for buffered async work.
Use Event Hub for high-throughput append-only event streams.
Use Blob trigger for object lifecycle processing.
Use Cosmos DB trigger for change feed processors.
Use Timer for scheduled maintenance and compaction jobs.
Use Durable triggers for multi-step stateful workflows.

Common pitfalls¶

Missing connection setting names.
Using trigger-specific SDK types without correct package versions.
Assuming at-least-once triggers are exactly once.
Performing long CPU work in HTTP handlers instead of offloading.
Forgetting to configure dead-letter/retry/idempotency strategy.

Microsoft Learn links by trigger¶

Triggers and bindings overview: https://learn.microsoft.com/azure/azure-functions/functions-triggers-bindings
HTTP trigger: https://learn.microsoft.com/azure/azure-functions/functions-bindings-http-webhook-trigger
Timer trigger: https://learn.microsoft.com/azure/azure-functions/functions-bindings-timer
Queue Storage trigger/binding: https://learn.microsoft.com/azure/azure-functions/functions-bindings-storage-queue
Blob trigger/binding: https://learn.microsoft.com/azure/azure-functions/functions-bindings-storage-blob
Event Hub trigger/binding: https://learn.microsoft.com/azure/azure-functions/functions-bindings-event-hubs
Service Bus trigger/binding: https://learn.microsoft.com/azure/azure-functions/functions-bindings-service-bus
Cosmos DB trigger/binding: https://learn.microsoft.com/azure/azure-functions/functions-bindings-cosmosdb-v2
Event Grid trigger/binding: https://learn.microsoft.com/azure/azure-functions/functions-bindings-event-grid
Warmup trigger: https://learn.microsoft.com/azure/azure-functions/functions-bindings-warmup
Durable Functions bindings: https://learn.microsoft.com/azure/azure-functions/durable/durable-functions-bindings