I want to be able to dynamically read the blob file (json) with Azure Function Python with the filename passed through Azure Event hub message. How can I do that with Azure Bindings?
function.json
{
"scriptFile": "__init__.py",
"bindings": [
{
"type": "eventHubTrigger",
"name": "events",
"direction": "in",
"eventHubName": "beta-api-intergration",
"connection": "receiverConnectionString",
"cardinality": "many",
"consumerGroup": "beta-api-consumer",
"dataType": "binary"
},
{
"name": "betablob",
"type": "blob",
"path": "swuploads/{filename}.json",
"connection": "AzureWebJobsStorage",
"direction": "in"
}
]
}
init.py
def main(events: List[func.EventHubEvent], betablob: func.InputStream):
well.login(user,pwd)
for event in events:
logging.info('Python EventHub trigger processed an event: %s', event.get_body().decode('utf-8'))
###msg contains the file name I want to load in blob
msg=parse_msg(event)
####how do I pass the file name here ?
data=load_blob(betablob)
Under normal circumstances, dynamic binding can be realized indirectly by passing in json format input (or trigger).
For example, send message like this:
{
"filename":"test"
}
And then binding will get the value 'test'.(This only works for language like python which use declarative bindings.)
But it seems that event hub cannot specify the format of the incoming information, so pure binding cannot be achieved. You need the python-based Azure SDK to implement dynamic binding.
Related
Hello I'm trying to figure out how to use azure functions binding to extract data from a trigger and use it in an input db for filtering. I'm using service bus message as a trigger. It seems that service bus bindings listed in Azure Functions documentation always return null for me, (even if inside a function this parameter has value set).
That's what i've been trying so far in example below, i want to extract ApplicationProperties.zoneId set inside a message.
function.json
"bindings": [
{
"name": "msg",
"type": "serviceBusTrigger",
"direction": "in",
"queueName": "myqueue",
"connection": "ServiceBusConnection"
},
{
"name": "documents",
"type": "cosmosDB",
"direction": "in",
"databaseName": "test_db",
"collectionName": "items",
"sqlQuery": "SELECT * from c where c.zoneId = {ApplicationProperties.zoneId}",
"connectionStringSetting": "CosmosDBConnection"
}]
for testing i'm sending test message to service bus:
def send_single_message(sender):
message = ServiceBusMessage(
"woah_a_test",
correlation_id="1",
subject="az-fcn",
)
message.application_properties = {"zoneId": 1}
sender.send_messages(message)
print("Sent a single message")
It seems quite strange for me that i could not access in function.json any of the trigger parameters (i've also tried CorrelationId and Subject), but inside of a triggered function those parameters return correct value.
I'm aware that i can bypass this issue by filtering inside a function code instead of using input binding, but I'm just curious why those params does not return expected value there. Is there any way to debug it?
So I have created a function app and now I am trying to create an API that connects to my Blob Storage and "Posts" the content within the container
import azure.functions as func
def main(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request.')
name = req.params.get('name')
if not name:
try:
req_body = req.get_json()
except ValueError:
pass
else:
name = req_body.get('name')
if name:
return func.HttpResponse(f"Hello, {name}. This HTTP triggered function executed successfully.")
else:
return func.HttpResponse(
"This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response.",
status_code=200
)
Thank you Anupam Chand. Posting your suggestions as an answer to help other community members.
The Output Binding allows you to connect to the blob storage using azure function.
Below is the sample code in how to connect to the Blob storage using output and input bindings.
{
"bindings": [
{
"queueName": "myqueue-items",
"connection": "MyStorageConnectionAppSetting",
"name": "queuemsg",
"type": "queueTrigger",
"direction": "in"
},
{
"name": "inputblob",
"type": "blob",
"dataType": "binary",
"path": "samples-workitems/{queueTrigger}",
"connection": "MyStorageConnectionAppSetting",
"direction": "in"
},
{
"name": "outputblob",
"type": "blob",
"dataType": "binary",
"path": "samples-workitems/{queueTrigger}-Copy",
"connection": "MyStorageConnectionAppSetting",
"direction": "out"
}
],
"disabled": false,
"scriptFile": "__init__.py"
}
For related information check Azure Blob output bindings.
I want to pull in cosmos documents into my azure function based on contents of eventgrid events that it triggers on (python worker runtime). Is it possible to do this?
I have below function.json:
{
"scriptFile": "__init__.py",
"bindings": [
{
"type": "eventGridTrigger",
"name": "event",
"direction": "in"
},
{
"name": "documents",
"type": "cosmosDB",
"databaseName": "Metadata",
"collectionName": "DataElementMappings",
"sqlQuery" : "SELECT * from c where c.id = {subject}",
"connectionStringSetting": "MyCosmosDBConnectionString",
"direction": "in"
}
]
}
I want to use properties of the event in the query for the cosmos input binding. I tried it with subject here. It fails with:
[6/4/2020 5:34:45 PM] System.Private.CoreLib: Exception while executing function: Functions.orch_taskchecker. System.Private.CoreLib: The given key 'subject' was not present in the dictionary.
So I am not using the right key name. The only key I got to work is {data} but unfortunately I was not able to access any properties inside the event data using the syntax {data.property} as it says in the docs. I would expect all of the event grid schema keys to be available to use in other bindings since an event is a JSON payload. I got none of them to work, e.g. eventTime, event_type, topic, etc.
Since I saw an example of the same idea for storage queues and they used for example {Queue.id} I tried things like {Event.subject}, {EventGridEvent.subject} all to no avail.
Nowhere in the docs can I find samples of event grid trigger data being used in other bindings. Can this be achieved?
For EventGridTrigger (C# script) can be used for input bindings a custom data object of the EventGridEvent class.
The following example shows a blob input bindings for event storage account:
{
"bindings": [
{
"type": "eventGridTrigger",
"name": "eventGridEvent",
"direction": "in"
},
{
"type": "blob",
"name": "body",
"path": "{data.url}",
"connection": "rk2018ebstg_STORAGE",
"direction": "in"
}
],
"disabled": false
}
Note, that only a property from the data object can be referenced.
There is the event.get_json() method that you can use to access the data field in the python code, I did not look at the bindings
I have an Azure Functions (Python 3) function that takes a message from a Service Bus queue and creates a Blob in a container as a result.
The function trigger is the Sevice Bus message. This message is a JSON object with several properties, one of which is the blob name.
The docs suggest something like this in the bindings:
{
"name": "outputblob",
"type": "blob",
"path": "samples-workitems/{queueTrigger}-Copy",
"connection": "MyStorageConnectionAppSetting",
"direction": "out"
}
But this suggest that the triggering message contains just the blob name. I can not make the message solely the blob name as I require the other attributes in the message to determine what to do / what data to put in the blob.
Is there any way to use the output bindings that will resolve this for me?
Thanks.
Yes, this could be done. You could just set the input and output binding path with the json value from the trigger json data. The below is my function.json. Use service bus trigger get the input blob name and output blob name, then write the input blob to the output blob. You could also set the container name with this way.
{
"scriptFile": "__init__.py",
"bindings": [
{
"name": "msg",
"type": "serviceBusTrigger",
"direction": "in",
"queueName": "myqueue",
"connection": "servicebuscon"
},
{
"name": "inputblob",
"type": "blob",
"path": "inputcontainer/{blobname}",
"connection": "AzureWebJobsStorage",
"direction": "in"
},
{
"name": "outputblob",
"type": "blob",
"path": "outputcontainer/{outblobname}",
"connection": "AzureWebJobsStorage",
"direction": "out"
}
]
}
And the below is the function code.
import logging
import azure.functions as func
import json, os
def main(msg: func.ServiceBusMessage,inputblob: func.InputStream,outputblob: func.Out[bytes]) -> func.InputStream:
logging.info('Python ServiceBus queue trigger processed message: %s',
msg.get_body().decode('utf-8'))
jsonData= json.loads(inputblob.read())
logging.info(jsonData)
outputblob.set(str(jsonData))
And I set the service bus message like below message.
Here is the result pic. You could find the input blob json data shown in the console and I check the container the output blob is created.
I have an azure function which is triggered by a file being put into blob storage and I was wondering how (if possible) to get the name of the blob (file) which triggered the function, I have tried doing:
fileObject=os.environ['inputBlob']
message = "Python script processed input blob'{0}'".format(fileObject.fileName)
and
fileObject=os.environ['inputBlob']
message = "Python script processed input blob'{0}'".format(fileObject.name)
but neither of these worked, they both resulted in errors. Can I get some help with this or some suggesstions?
Thanks
The blob name can be captured via the Function.json and provided as binding data. See the {filename} token below.
Function.json is language agnostic and works in all languages.
See documentation at https://learn.microsoft.com/en-us/azure/azure-functions/functions-triggers-bindings for details.
{
"bindings": [
{
"name": "image",
"type": "blobTrigger",
"path": "sample-images/{filename}",
"direction": "in",
"connection": "MyStorageConnection"
},
{
"name": "imageSmall",
"type": "blob",
"path": "sample-images-sm/{filename}",
"direction": "out",
"connection": "MyStorageConnection"
}
],
}
If you want to get the file name of the file that triggered your function you can to that:
Use {name} in function.json :
{
"bindings": [
{
"name": "myblob",
"type": "blobTrigger",
"path": "MyBlobPath/{name}",
"direction": "in",
"connection": "MyStorageConnection"
}
]
}
The function will be triggered by changes in yout blob storage.
Get the name of the file that triggered the function in python (init.py):
def main(myblob: func.InputStream):
filemane = {myblob.name}
Will give you the name of the file that triggered your function.
There is not any information about what trigger you used in your description. But fortunately， there is a sample project yokawasa/azure-functions-python-samples on GitHub for Azure Function using Python which includes many samples using different triggers like queue trigger or blob trigger. I think it's very helpful for you now, and you can refer to these samples to write your own one to satisfy your needs。
Hope it helps.
Getting the name of the inputBlob is not currently possible with Python Azure-Functions. There are open issues about it in azure-webjobs-sdk and azure-webjobs-sdk-script GitHub:
https://github.com/Azure/azure-webjobs-sdk/issues/1090
https://github.com/Azure/azure-webjobs-sdk-script/issues/1339
Unfortunatelly it's still not possible.
In Python, you can do:
import azure.functions as func
import os
def main(blobin: func.InputStream):
filename=os.path.basename(blobin.name)