Azure Functional Binding

Question

I cannot associate an input parameter of type blob with the string / TextReader without using [BlobAttribute] in the C # implementation (not CSX).

The error I get is:

Microsoft.Azure.WebJobs.Host: Error indexing method 'Functions.Harvester'. 
Microsoft.Azure.WebJobs.Host: Cannot bind parameter 'configReader' to type 
TextReader. Make sure the parameter Type is supported by the binding. If 
you're using binding extensions (e.g. ServiceBus, Timers, etc.) make sure 
you've called the registration method for the extension(s) in your startup 
code (e.g. config.UseServiceBus(), config.UseTimers(), etc.).

function.config:

"bindings": [
    {
      "type": "timerTrigger",
      "schedule": "0 */5 * * * *",
      "useMonitor": true,
      "runOnStartup": false,
      "direction": "in",
      "name": "myTimer"
    },
    {
      "type": "blob",
      "name": "configReader",
      "path": "secured/app.config.json",
      "connection": "XXX",
      "direction": "in"
    }
  ],

Function Signature (NOT BINDING configReader):

[FunctionName("Harvester")]
 public static async Task Run(
   [TimerTrigger("0 */5 * * * *")]TimerInfo myTimer,
   TraceWriter log,
   TextReader configReader)

This will work (BINDING configReader:

[FunctionName("Harvester")]
 public static async Task Run(
   [TimerTrigger("0 */5 * * * *")]TimerInfo myTimer,
   TraceWriter log,
   [Blob("secured/app.config.json", FileAccess.Read)]TextReader configReader)

Any idea on how to make it work without specifying a blob's path BlobAttribute. I would ideally save the Blob configuration outside of the code, this way my function will become more portable.

Answer 1

The problem turned out to be with the latest version supporting the new property ( configurationSource) infunction.json

, config ( function.json), # config.

, ,

[FunctionName("Harvester")]
public static async Task Run(
    [TimerTrigger]TimerInfo myTimer,
    TraceWriter log,
    TextReader configReader)
{
}

function.json,

{
  "generatedBy": "Microsoft.NET.Sdk.Functions-1.0.0.0",
  "configurationSource": "config",
  "bindings": [
    {
      "type": "timerTrigger",
      "schedule": "0 */5 * * * *",
      "useMonitor": true,
      "runOnStartup": false,
      "direction": "in",
      "name": "myTimer"
    },
    {
      "type": "blob",
      "name": "configReader",
      "path": "secured/app.config.json",
      "connection": "XXX",
      "direction": "in"
    }
  ],
  "disabled": false,
  "scriptFile": "...",
  "entryPoint": "..."
}

[FunctionName("Harvester")]
public static async Task Run(
    [TimerTrigger("0 */5 * * * *")]TimerInfo myTimer,
    TraceWriter log,
    [Blob("secured/app.config.json", FileAccess.Read)]TextReader configReader)
{
}

,

{
  "generatedBy": "Microsoft.NET.Sdk.Functions-1.0.0.0",
  "configurationSource": "attributes",
  "bindings": [
    {
      "type": "timerTrigger",
      "name": "myTimer"
    },
  ],
  "scriptFile": "...",
  "entryPoint": "..."
}

configurationSource .

Visual Studio 2017 . function.json, configurationSource, . GIF , .