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Merge pull request #290339 from ggailey777/ignite-updates
[Functions] Victoria's Python fixes for Event Grid Blob trigger tutorial
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‎articles/azure-functions/functions-event-grid-blob-trigger.md

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@@ -68,7 +68,7 @@ When you create a Blob Storage trigger function using Visual Studio Code, you al
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Don't choose a project folder that's already part of a workspace.
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1. At the prompts, provide the following information:
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1. At the prompts, provide the following information:
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::: zone pivot="programming-language-csharp"
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|Prompt|Action|
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|**Provide a function name**| Enter `EventGridBlobTrigger`. |
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|**Provide a namespace** | Enter `My.Functions`. |
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|**Select setting from "local.settings.json"**| Select `Create new local app setting`. |
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|**Select subscription**| Select your subscription.|
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|**Select subscription**| Select your subscription, if needed.|
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|**Select a storage account**| Use Azurite emulator for local storage. |
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|**The path within your storage account that the trigger will monitor**| Accept the default value `samples-workitems`. |
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|**Select how you would like to open your project**| Select `Open in current window`. |
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|Prompt|Action|
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|--|--|
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|**Select a language**| Select `Python`. |
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|**Select a Python programming model** | Select `V1` |
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|**Select a Python programming model** | Select `Model V2` |
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|**Select a Python interpreter to create a virtual environment**| Select your preferred Python interpreter. If an option isn't shown, enter the full path to your Python binary. |
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|**Select a template for your project's first function**| Select `Azure Blob Storage trigger (using Event Grid)`. |
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|**Select a template for your project's first function**| Select `Blob trigger`. (The event-based template isn't yet available.)|
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|**Provide a function name**| Enter `EventGridBlobTrigger`. |
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|**The path within your storage account that the trigger will monitor**| Accept the default value `samples-workitems`. |
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|**Select setting from "local.settings.json"**| Select `Create new local app setting`. |
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|**Select subscription**| Select your subscription.|
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|**Select subscription**| Select your subscription, if needed.|
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|**Select a storage account**| Use Azurite emulator for local storage. |
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|**The path within your storage account that the trigger will monitor**| Accept the default value `samples-workitems`. |
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|**Select how you would like to open your project**| Select `Open in current window`. |
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::: zone-end
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::: zone-end
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::: zone pivot="programming-language-java"
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|Prompt|Action|
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|--|--|
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|**Select how you would like to open your project**| Select `Open in current window`. |
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An HTTP triggered function (`HttpExample`) is created for you. You won't use this function and must instead create a new function.
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::: zone-end
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::: zone pivot="programming-language-typescript"
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::: zone-end
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::: zone pivot="programming-language-typescript"
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|Prompt|Action|
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|--|--|
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|**Select a language for your function project**| Select `TypeScript`. |
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|**Select a TypeScript programming model**| Select `Model V4`. |
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|**Select a template for your project's first function**| Select `Azure Blob Storage trigger (using Event Grid)`. |
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|**Provide a function name**| Enter `EventGridBlobTrigger`. |
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|**Select setting from "local.settings.json"**| Select `Create new local app setting`. |
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|**Select subscription**| Select your subscription.|
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|**Select subscription**| Select your subscription, if needed.|
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|**Select a storage account**| Use Azurite emulator for local storage. |
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|**The path within your storage account that the trigger will monitor**| Accept the default value `samples-workitems`. |
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|**Select how you would like to open your project**| Select `Open in current window`. |
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|**Select a template for your project's first function**| Select `Azure Blob Storage trigger (using Event Grid)`. |
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|**Provide a function name**| Enter `eventGridBlobTrigger`. |
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|**Select setting from "local.settings.json"**| Select `Create new local app setting`. |
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|**Select subscription**| Select your subscription.|
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|**Select subscription**| Select your subscription, if needed.|
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|**Select a storage account**| Use Azurite emulator for local storage. |
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|**The path within your storage account that the trigger will monitor**| Accept the default value `samples-workitems`. |
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|**Select how you would like to open your project**| Select `Open in current window`. |
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|**Select a template for your project's first function**| Select `Azure Blob Storage trigger (using Event Grid)`. |
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|**Provide a function name**| Enter `EventGridBlobTrigger`. |
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|**Select setting from "local.settings.json"**| Select `Create new local app setting`. |
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|**Select subscription**| Select your subscription.|
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|**Select subscription**| Select your subscription, if needed.|
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|**Select a storage account**| Use Azurite emulator for local storage. |
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|**The path within your storage account that the trigger will monitor**| Accept the default value `samples-workitems`. |
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|**Select how you would like to open your project**| Select `Open in current window`. |
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You now have a function that can be triggered by events in a Blob Storage container.
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## (Optional) Review the code
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::: zone pivot="programming-language-python"
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## Update the trigger source
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You first need to switch the trigger source from the default Blob trigger source (container polling) to an event subscription source.
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1. Open the function_app.py project file and you see a definition for the `EventGridBlobTrigger` function with the `blob_trigger` decorator applied.
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1. Update the decorator by adding `source = "EventGrid"`. Your function should now look something like this:
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```python
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@app.blob_trigger(arg_name="myblob", source="EventGrid", path="samples-workitems",
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connection="<STORAGE_ACCOUNT>")
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def EventGridBlobTrigger(myblob: func.InputStream):
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logging.info(f"Python blob trigger function processed blob"
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f"Name: {myblob.name}"
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f"Blob Size: {myblob.length} bytes")
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```
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In this definition `source = "EventGrid"` indicates that an event subscription to the `samples-workitems` blob container is used as the source of the event that starts the trigger.
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::: zone-end
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::: zone pivot="programming-language-csharp,programming-language-typescript,programming-language-powershell,programming-language-java,programming-language-javascript"
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## (Optional) Review the code
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::: zone-end
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::: zone pivot="programming-language-csharp"
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Open the generated `EventGridBlobTrigger.cs` file and you see a definition for an `EventGridBlobTrigger` function that looks something like this:
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In this definition `source = EventGrid` indicates that an event subscription to the `samples-workitems` blob container is used as the source of the event that starts the trigger.
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::: zone-end
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::: zone pivot="programming-language-python,programming-language-powershell"
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::: zone pivot="programming-language-powershell"
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In the `EventGridBlobTrigger` folder, open the `function.json` file and find a binding definition like this with a `type` of `blobTrigger` and a `source` of `EventGrid`:
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:::code language="json" source="~/functions-quickstart-templates/Functions.Templates/Templates/EventGridBlobTrigger-PowerShell/function.json" :::
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To create an event subscription, you need to provide Event Grid with the URL of the specific endpoint to report Blob Storage events. This _blob extension_ URL is composed of these parts:
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| Part | Example |
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| --- | --- |
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| Part | Example |
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| --- |-------------------------------------------------|
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| Base function app URL | `https://<FUNCTION_APP_NAME>.azurewebsites.net` |
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| Blob-specific path | `/runtime/webhooks/blobs` |
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| Function query string | `?functionName=Host.Functions.EventGridBlobTrigger` |
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| Blob extension access key | `&code=<BLOB_EXTENSION_KEY>` |
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| Blob-specific path | `/runtime/webhooks/blobs` |
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| Function query string | `?functionName=Host.Functions.<FUNCTION_NAME>` |
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| Blob extension access key | `&code=<BLOB_EXTENSION_KEY>` |
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The blob extension access key is designed to make it more difficult for others to access your blob extension endpoint. To determine your blob extension access key:
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https://<FUNCTION_APP_NAME>.azurewebsites.net/runtime/webhooks/blobs?functionName=Host.Functions.EventGridBlobTrigger&code=<BLOB_EXTENSION_KEY>
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```
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In this example, replace `<FUNCTION_APP_NAME>` with the name of your function app and replace `<BLOB_EXTENSION_KEY>` with the value you got from the portal. If you used a different name for your function, you'll also need to change the `functionName` query string value to your function name.
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In this example, replace `<FUNCTION_APP_NAME>` with the name of your function app, and `<BLOB_EXTENSION_KEY>` with the value you got from the portal. If you used a different name for your function, replace `EventGridBlobTrigger` with that function name.
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You can now use this endpoint URL to create an event subscription.
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1. Sign in to the [Azure portal](https://portal.azure.com) and make a note of the **Resource group** for your storage account. You create your other resources in the same group to make it easier to clean up resources when you're done.
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1. select the **Events** option from the left menu.
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1. Select the **Events** option from the left menu.
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![Add storage account event](./media/functions-event-grid-blob-trigger/functions-event-grid-local-dev-add-event.png)
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| **Endpoint** | Your Azure-based URL endpoint | Use the URL endpoint that you built, which includes the key value. |
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1. Select **Confirm selection** to validate the endpoint URL.
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2. Select the **Filters** tab and provide the following information to the prompts:
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| Setting | Suggested value | Description |
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|------------------------------|-----------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| **Enable subject filtering** | *Enabled* | Enables filtering on which blobs can trigger the function. |
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| **Subject Begins With** | **`/blobServices/default/containers/<CONTAINER_NAME>/blobs/<BLOB_PREFIX>`** | Replace `<CONTAINER_NAME` and `<BLOB_PREFIX>` with values you choose. This sets the subscription to trigger only for blobs that start with `BLOB_PREFIX` and are in the `CONTAINER_NAME` container. |
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| **Subject Ends With** | *.txt* | Ensures that the function will only be triggered by blobs ending with `.txt`. |
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For more information on filtering to specific blobs, see [Event Filtering for Azure Event Hubs](../event-grid/event-filtering.md).
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1. Select **Create** to create the event subscription.
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7. Select **Create** to create the event subscription.
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## Upload a file to the container
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## Next steps
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+ [Working with blobs](storage-considerations.md#working-with-blobs)
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- [Working with blobs](storage-considerations.md#working-with-blobs)
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- [Automate resizing uploaded images using Event Grid](../event-grid/resize-images-on-storage-blob-upload-event.md)
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- [Event Grid trigger for Azure Functions](./functions-bindings-event-grid.md)

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