Which values can DocumentClientException.Error.Code have? - exception

Question

I want my data access layer to handle exceptions thrown by DocumentDB API provided via Microsoft.Azure.Documents.Client.DocumentClient class. For example, the optimistic concurrency check implemented using AccessCondition class, but others as well.
By looking at the exception thrown, the best way to recognize different DocumentClient-specific exceptions seems to be something like this:
try { ... }
catch (DocumentClientException exception)
when (exception.Error.Code == "Some magic here")
{
//let the user know how to recover from this..
}
I don't like such magic strings as they are not verifiable compile-time. It may contract a typo, or it may change on random moment with DocumentDB client/server changes, etc. Also, it is not clear which such magic codes I could/should be handling since I don't see the Microsoft.Azure.DocumentDB .net API containing any ErrorCodes enum or constants, nor find any list in documentation.
Where can I find a list of possible Error.Code values DocumentClient API can throw?
To make it even more confusing, the XmlDoc for DocumentClient.CreateDocumentAsync method suggest working instead on http status codes.
UPDATE: This question is not about Http status codes but DocumentClientException.Error.Code field as I assume the latter is more precise.

Answer 1

Where can I find a list of possible error codes values DocumentClient API can throw?
It's hard to find the completely list of error code that DocumentClinet API throw. The exception is depend on what your request.
For example, the optimistic concurrency check
Azure Cosmos DB uses ETags for handling optimistic concurrency.
When we retrieve a document from Azure Cosmos DB, it always contains an ETag property as apart of our document.
When we then want to send our request to replace a document, we can specify an AccessCondition with the ETag we received when we fetched out our document.
If the ETag we send is not current, the server will return a 412 Precondition Failed status code. In our .NET SDK, this is wrapped up in a DocumentClientException.
Here is an example that show the possible problems when the concurrency occurred.

Answer 2

By decompile the version 1.22.0 client, the code is set as a HttpStatusCode enum. I think all the possible values can be found here https://msdn.microsoft.com/en-us/library/system.net.httpstatuscode(v=vs.110).aspx then.
However, what really contains richer information for debug is the Error.Message. Might need to decompile the whole library to figure out, or wait for Microsoft to release the source codes, which is unlikely to happen since the latest update in github was 2 or 3 years ago.
public Error Error
{
get
{
if (this.error == null)
{
this.error = new Error()
{
Code = this.StatusCode.ToString(),
Message = this.Message
};
}
return this.error;
}
}

Answer 3

There is a list of the HTTP Status Codes for Azure Cosmos DB
I use the following code in my catch blocks
catch (DocumentClientException e)
{
var resp = new HttpResponseMessage
{
StatusCode = (HttpStatusCode) e.StatusCode,
Content = new StringContent(e.Message)
};
return resp;
}
Letting the user know how to handle the exception should be done on the client application.