'Send an Email' parameter 'attachment content' cannot be null - azure-logic-apps

Question

I'm creating an Azure Logic App to email a CSV file with data. When there is no data, the Send_an_email_(V2) step is failing and I see the following error in its output:
Parameter 'Attachment Content' cannot be null or empty.
The Send_an_email_(V2) action in the Azure Logic App gets part of it's input from the output of a preceding Create_CSV_table action. It uses the body of the Create_CSV_table output as shown below, in order to construct ContentBytes for an email attachment:
"actions": {
"Create_CSV_table": {
"inputs": {
"format": "CSV",
"from": "#body('Parse_JSON')"
},
"runAfter": {
"Parse_JSON": [
"Succeeded"
]
},
"type": "Table"
},
"Send_an_email_(V2)": {
"inputs": {
"body": {
"Attachments": [
{
"ContentBytes": "#{base64(body('Create_CSV_table'))}",
"Name": "report.csv"
}
],
"Body": "<p></p>",
"Subject": "My Report",
"To": "me#email.com"
},
"host": {
"connection": {
"name": "#parameters('$connections')['office365']['connectionId']"
}
},
"method": "post",
"path": "/v2/Mail"
},
"runAfter": {
"Create_CSV_table": [
"Succeeded"
]
},
"type": "ApiConnection"
}
When there is no data input into the Create_CSV_table step, the Create_CSV_table step is successful, and the raw output for the Create_CSV_table step shows an empty body as follows:
{
"body": ""
}
Raw input for the failing Send_an_email_(V2) step
{
HTTP stuff ...,
"body": {
"Attachments": [
{
"ContentBytes": "",
"Name": "report.csv"
}
],
"Body": "<p></p>",
"Subject": "Report",
"To": "me#mail.com"
}
}
Raw output for the failing Send_an_email_(V2) step
{
HTTP stuff ...,
"body": {
"status": 400,
"message": "Parameter 'Attachment Content' cannot be null or empty.\r\nclientRequestId: 887e3968-c7e9-4c35-b588-f76fd0e51545",
"error": {
"message": "Parameter 'Attachment Content' cannot be null or empty."
},
"source": "office365-ase.azconn-ase.p.azurewebsites.net"
}
}
How do I handle this? Do I need to implement my own null handling for the "ContentBytes" of the Send_an_email_(V2) input? If so, how do I do that? Or is there another way to handle this. I want an empty email to be sent when there is no CSV content.
I figured out that #{base64(body('Create_CSV_table'))} is an Azure Logic Apps expression (denoted by #), containing functions that act on the JSON for the body of the output of Create_CSV_table and that the enclosing {} results in the output of the expression being a string.

Answer 1

After the Last step you can send to storage account using Create blob(V2) Connection with .csv file extension and then send the same blob content using Get blob content(V2) Connection then Send an email.
Here are the screenshots of LogicApp
In outlook:
Here is the workflow
{
"definition": {
"$schema": "https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#",
"actions": {
"Create_CSV_table_2": {
"inputs": {
"format": "CSV",
"from": "#variables('Array')"
},
"runAfter": {
"For_each_2": [
"Succeeded"
]
},
"type": "Table"
},
"Create_blob_(V2)": {
"inputs": {
"body": "#body('Create_CSV_table_2')",
"headers": {
"ReadFileMetadataFromServer": true
},
"host": {
"connection": {
"name": "#parameters('$connections')['azureblob']['connectionId']"
}
},
"method": "post",
"path": "/v2/datasets/#{encodeURIComponent(encodeURIComponent('AccountNameFromSettings'))}/files",
"queries": {
"folderPath": "/ch1container2408",
"name": "TestSample1.csv",
"queryParametersSingleEncoded": true
}
},
"runAfter": {
"Create_CSV_table_2": [
"Succeeded"
]
},
"runtimeConfiguration": {
"contentTransfer": {
"transferMode": "Chunked"
}
},
"type": "ApiConnection"
},
"For_each_2": {
"actions": {
"Append_to_array_variable": {
"inputs": {
"name": "Array",
"value": {
"created_at": "#items('For_each_2')['created_at']",
"funds": "#items('For_each_2')['funds']",
"id": "#items('For_each_2')['id']",
"pair": "#items('For_each_2')['market']",
"price": "#items('For_each_2')['price']",
"side": "#items('For_each_2')['side']",
"volume": "#items('For_each_2')['volume']"
}
},
"runAfter": {},
"type": "AppendToArrayVariable"
}
},
"foreach": "#body('Parse_JSON')",
"runAfter": {
"Initialize_variable_2": [
"Succeeded"
]
},
"type": "Foreach"
},
"Get_blob_content_(V2)": {
"inputs": {
"host": {
"connection": {
"name": "#parameters('$connections')['azureblob']['connectionId']"
}
},
"method": "get",
"path": "/v2/datasets/#{encodeURIComponent(encodeURIComponent('AccountNameFromSettings'))}/files/#{encodeURIComponent(encodeURIComponent('/<Your Container>','/<Your File>.csv'))}/content",
"queries": {
"inferContentType": true
}
},
"runAfter": {
"Create_blob_(V2)": [
"Succeeded"
]
},
"type": "ApiConnection"
},
"HTTP": {
"inputs": {
"method": "GET",
"uri": "https://api.wazirx.com/api/v2/trades?market=btcusdt"
},
"runAfter": {},
"type": "Http"
},
"Initialize_variable": {
"inputs": {
"variables": [
{
"name": "Array",
"type": "array"
}
]
},
"runAfter": {
"Parse_JSON": [
"Succeeded"
]
},
"type": "InitializeVariable"
},
"Initialize_variable_2": {
"inputs": {
"variables": [
{
"name": "Table",
"type": "array"
}
]
},
"runAfter": {
"Initialize_variable": [
"Succeeded"
]
},
"type": "InitializeVariable"
},
"Parse_JSON": {
"inputs": {
"content": "#body('HTTP')",
"schema": {
"items": {
"properties": {
"created_at": {
"type": "string"
},
"funds": {
"type": "string"
},
"id": {
"type": "integer"
},
"market": {
"type": "string"
},
"price": {
"type": "string"
},
"side": {},
"volume": {
"type": "string"
}
},
"required": [
"id",
"market",
"price",
"volume",
"funds",
"created_at",
"side"
],
"type": "object"
},
"type": "array"
}
},
"runAfter": {
"HTTP": [
"Succeeded"
]
},
"type": "ParseJson"
},
"Send_an_email_(V2)": {
"inputs": {
"body": {
"Attachments": [
{
"ContentBytes": "#{base64(body('Get_blob_content_(V2)'))}",
"Name": "#body('Create_blob_(V2)')?['Name']"
}
],
"Body": "<p>TABLE TEST</p>",
"Subject": "Test",
"To": "<To Address>"
},
"host": {
"connection": {
"name": "#parameters('$connections')['office365']['connectionId']"
}
},
"method": "post",
"path": "/v2/Mail"
},
"runAfter": {
"Get_blob_content_(V2)": [
"Succeeded"
]
},
"type": "ApiConnection"
}
},
"contentVersion": "1.0.0.0",
"outputs": {},
"parameters": {
"$connections": {
"defaultValue": {},
"type": "Object"
}
},
"triggers": {
"manual": {
"inputs": {},
"kind": "Http",
"type": "Request"
}
}
},
"parameters": {
"$connections": {
"value": {
"azureblob": {
"connectionId": "<Your ConnectionId>",
"connectionName": "azureblob",
"id": "<Id>"
},
"office365": {
"connectionId": "<Your ConnectionId>",
"connectionName": "office365",
"id": "<Your Id>"
}
}
}
}
}