dotnet/orleans · error · ArgumentNullException

service

Error message

service

What it means

Thrown by the DynamoDBStorage constructor when the service argument (the AWS region/service identifier, e.g. 'us-west-2') is null. The constructor uses nameof(service) so the thrown ArgumentNullException reports the parameter name 'service'. service drives RegionEndpoint selection in CreateClient, so a null value cannot proceed.

Source

Thrown at src/AWS/Shared/Storage/DynamoDBStorage.cs:85

        /// <param name="readCapacityUnits"></param>
        /// <param name="writeCapacityUnits"></param>
        /// <param name="useProvisionedThroughput"></param>
        /// <param name="createIfNotExists"></param>
        /// <param name="updateIfExists"></param>
        public DynamoDBStorage(
            ILogger logger,
            string service,
            string? accessKey = "",
            string? secretKey = "",
            string? token = "",
            string? profileName = "",
            int readCapacityUnits = DefaultReadCapacityUnits,
            int writeCapacityUnits = DefaultWriteCapacityUnits,
            bool useProvisionedThroughput = true,
            bool createIfNotExists = true,
            bool updateIfExists = true)
        {
            if (service == null) throw new ArgumentNullException(nameof(service));
            this._accessKey = accessKey;
            this.secretKey = secretKey;
            this._token = token;
            this._profileName = profileName;
            this._service = service;
            this._useProvisionedThroughput = useProvisionedThroughput;
            this._provisionedThroughput = this._useProvisionedThroughput
                ? new ProvisionedThroughput(readCapacityUnits, writeCapacityUnits)
                : null;
            this._createIfNotExists = createIfNotExists;
            this._updateIfExists = updateIfExists;
            _logger = logger;
            CreateClient();
        }

        /// <summary>
        /// Create a DynamoDB table if it doesn't exist
        /// </summary>

View on GitHub (pinned to fca799fa70)

Solutions

1. Set the Service/Region in the DynamoDB options (the AWS region system name, e.g. 'us-west-2').
2. If the region comes from configuration/environment, validate it is non-null before building the silo.
3. Provide a sensible default in your bootstrap code (e.g., fallback to a known region).
4. Check the specific options section (clustering vs persistence vs reminders vs transactions) that corresponds to the failing provider.

Example fix

// before: Service not set
silo.AddDynamoDBTransactionalGrainStorage("tx", opt => { opt.TableName = "tx"; });

// after: set the region
silo.AddDynamoDBTransactionalGrainStorage("tx", opt =>
{
    opt.Service = Environment.GetEnvironmentVariable("AWS_REGION") ?? "us-west-2";
    opt.TableName = "tx";
});

// Resolve and validate the region before building the silo
var region = Environment.GetEnvironmentVariable("AWS_REGION")
          ?? config["DynamoDB:Service"]
          ?? "us-west-2";
if (string.IsNullOrWhiteSpace(region))
    throw new InvalidOperationException("AWS region (Service) must be configured for DynamoDB storage");

static bool HasService(string? service) => !string.IsNullOrWhiteSpace(service);

try { silo.StartAsync(); }
catch (ArgumentNullException an) when (an.ParamName == "service")
{
    _logger.LogCritical("DynamoDB 'Service' (region) is null; set it in DynamoDBStorageOptions");
    throw;
}

When it happens

Trigger: Produced when constructing DynamoDBStorage (directly, or via a provider factory that passes options.Service) with service == null. Triggered by missing/empty 'Service' in DynamoDBStorageOptions / DynamoDBTransactionalStorageOptions / clustering/reminders options, or by a null being explicitly passed.

Common situations: Forgetting to set the 'Service' (region) property in configuration; reading the region from an environment variable/secret that resolved to null; misconfigured appsettings.json section; a test helper that constructs DynamoDBStorage without a region.

Related errors

• Table {tableDescription.TableName} has a status of {tableDes
• Configuration for DynamoDBGrainStorage {name} is invalid. Ta
• Configuration for DynamoDBGrainStorage {name} is invalid. Re
• Configuration for DynamoDBGrainStorage {name} is invalid. Wr
• Data too large to write to DynamoDB table. Size={dataSize} M

AI-assisted analysis of dotnet/orleans@fca799fa70 (2026-08-13). Data as JSON: /api/errors/9b60c8bb043de20d. Report an issue: GitHub.