Get cosmosdb connectionstring in Azure Function

gistfile1.txt

  builder.Services.PostConfigure<CosmosDBOptions>(options =>
            {
                if (string.IsNullOrWhiteSpace(managedIdentity))
                {
                    // When local, read it from the config. Most likely from the not checked in local.settings.json file
                    options.ConnectionString = configuration.GetValue<string>(CosmosDbConfig.ConnectionStringSetting);
                }
                else
                {
                    // If we do have a managed identity, we can fetch the keys from Azure
                    var task = azureServiceTokenProvider.GetAccessTokenAsync("https://management.azure.com/");
                    string token = task.Result;

                    var subscriptionId = configuration.GetValue<string>("cosmosDb:subscriptionId");
                    var tenantId = configuration.GetValue<string>("cosmosDb:tenantId");
                    var cosmosDbName = configuration.GetValue<string>("cosmosDb:dbName");
                    var resourceGroup = configuration.GetValue<string>("cosmosDb:resourceGroup");

                    var tokenCredentials = new TokenCredentials(token);
                    var azureCredentials = new AzureCredentials(
                        tokenCredentials,
                        tokenCredentials,
                        tenantId,
                        AzureEnvironment.AzureGlobalCloud);
                    var client = RestClient
                        .Configure()
                        .WithEnvironment(AzureEnvironment.AzureGlobalCloud)
                        .WithLogLevel(HttpLoggingDelegatingHandler.Level.Basic)
                        .WithCredentials(azureCredentials)
                        .Build();
                    var azure = Azure
                        .Authenticate(client, tenantId)
                        .WithSubscription(subscriptionId);

                    var cosmosDbAccounts = azure.CosmosDBAccounts;
                    var readWriteKeys = cosmosDbAccounts.ListKeysAsync(resourceGroup, cosmosDbName);
                    var keys = readWriteKeys.Result;

                    options.ConnectionString =
                        $"AccountEndpoint=https://{cosmosDbName}.documents.azure.com:443/;AccountKey={keys.PrimaryMasterKey};";
                }
            });