Azure function to store csv data in Cosmos DB

This is a http trigger function written in C# - .NET Core 3.1. It processed a csv file and store the data on Cosmos DB

GitHub repo : https://github.com/hansamaligamage/fncsvdatastore

Technology stack

• .NET Core 3.1 on Visual Studio 2019
• Azure functions v3 and Azure Cosmos DB table API

Some code snippets

Retrieve the database storage account

public static CloudStorageAccount RetieveStorageAccount(string storageConnectionString) 
{ 
    CloudStorageAccount storageAccount; 
    try 
    { 
       storageAccount = CloudStorageAccount.Parse(storageConnectionString); 
    } 
    catch (FormatException) 
    { 
       Console.WriteLine("Invalid storage account information provided"); 
       throw; 
    } 
    catch (ArgumentException) 
    { 
       Console.WriteLine("Please check the storage account details"); 
       Console.ReadLine(); 
       throw; 
    } 
    catch(Exception ex) 
    { 
       throw ex; 
    } 
    return storageAccount; 
 }

Create a table in Cosmos DB


public static string LoadConnectionDetails() 
{ 
    return Environment.GetEnvironmentVariable("StorageConnectionString"); 
}

public static async Task<CloudTable> CreateTableAsync(string tableName)
{
    CloudTable table;
    string storageConnectionString = LoadConnectionDetails();
    CloudStorageAccount storageAccount = RetieveStorageAccount(storageConnectionString);
    CloudTableClient tableClient = storageAccount.CreateCloudTableClient(new TableClientConfiguration());
    Console.WriteLine("Table client is created");
    try
    {
        table = tableClient.GetTableReference(tableName);
        if (await table.CreateIfNotExistsAsync())
        {
            Console.WriteLine("Table is created - {0}", tableName);
        }
        else
        {
            Console.WriteLine("Table {0} already exists", tableName);
        }
    }
    catch (Exception ex)
    {
        throw ex;
    }
    Console.WriteLine();
    return table;

}

Create a row in the Cosmos DB

public static async Task InsertOrUpdateEntityAsync(CloudTable table, Session session) 
{ 
   if (session == null) 
   { 
      throw new ArgumentNullException("Session is empty"); 
   } 
  try 
  { 
     TableOperation tableOperation = TableOperation.InsertOrMerge(session); 
     TableResult result = await table.ExecuteAsync(tableOperation); 
     Session newSession = result.Result as Session; 
     if (result.RequestCharge.HasValue) 
     { 
        Console.WriteLine("Request Charge of the operation: " + result.RequestCharge); 
     } 
     return newSession; 
 } 
 catch (StorageException e) 
 { 
    Console.WriteLine(e.Message); 
    Console.ReadLine(); 
    throw; 
 } 
 catch (Exception ex) 
 { 
    throw ex; 
 } 
}

Read a row in the Cosmos DB

public static async Task RetrieveEntityAsync(CloudTable table, string partitionKey, string rowKey) 
{ 
   try 
   { 
      TableOperation tableOperation = TableOperation.Retrieve(partitionKey, rowKey);
      TableResult result = await table.ExecuteAsync(tableOperation); 
      Session session = result.Result as Session; 
      if (session != null) 
      { 
         Console.WriteLine("\t{0}\t{1}\t{2}\t{3}", session.PartitionKey, session.RowKey,                               session.Points, session.IsWeekend); 
      } 
      if (result.RequestCharge.HasValue) 
      { 
         Console.WriteLine("Request Charge of Retrieve Operation: " +                                                     result.RequestCharge); 
      } 
      return session; 
  } 
  catch (StorageException e) 
  { 
     Console.WriteLine(e.Message); 
     Console.ReadLine(); 
     throw; 
  } 
 catch (Exception ex) 
 { 
    throw ex; 
 } 
}

Data types in Azure Cosmos DB SQL API

Check this video to understand how to model a Cosmos DB for a sample bookstore by going through the set of business requirements

Video : https://www.youtube.com/watch?v=Mz7FgEo3LFg&t=18s