HTTP interface for Stream Transactions

Stream Transactions allow you to perform a multi-document transaction with individual begin and commit/abort commands

For an introduction to this transaction type, see Stream Transactions.

To use a Stream Transaction, a client first sends the configuration of the transaction to the ArangoDB server.

Contrary to JavaScript Transactions, the definition of Stream Transaction must only contain the collections that are going to be used and (optionally) the various transaction options supported by ArangoDB. No action attribute is supported.

The Stream Transaction API works in conjunction with other APIs in ArangoDB. To use the transaction for a supported operation a client needs to specify the transaction identifier in the x-arango-trx-id HTTP header on each request. This will automatically cause these operations to use the specified transaction.

Supported transactional API operations include:

Begin a Stream Transaction

post /_api/transaction/begin

Begin a Stream Transaction that allows clients to call selected APIs over a short period of time, referencing the transaction ID, and have the server execute the operations transactionally.

Committing or aborting a running transaction must be done by the client. It is bad practice to not commit or abort a transaction once you are done using it. It forces the server to keep resources and collection locks until the entire transaction times out.

The transaction description must be passed in the body of the POST request. If the transaction can be started on the server, HTTP 201 will be returned.

For successfully started transactions, the returned JSON object has the following properties:

  • error: boolean flag to indicate if an error occurred (false in this case)

  • code: the HTTP status code

  • result: result containing

    • id: the identifier of the transaction
    • status: containing the string ‘running’

If the transaction specification is either missing or malformed, the server will respond with HTTP 400 or HTTP 404.

The body of the response will then contain a JSON object with additional error details. The object has the following attributes:

  • error: boolean flag to indicate that an error occurred (true in this case)

  • code: the HTTP status code

  • errorNum: the server error number

  • errorMessage: a descriptive error message

Path Parameters
    Query Parameters
      HTTP Headers
      • Set this header to true to allow the Coordinator to ask any shard replica for the data, not only the shard leader. This may result in “dirty reads”.

        This header decides about dirty reads for the entire transaction. Individual read operations, that are performed as part of the transaction, cannot override it.

      Request Body application/json
      • Allow reading from undeclared collections.

      • collections must be a JSON object that can have one or all sub-attributes read, write or exclusive, each being an array of collection names or a single collection name as string. Collections that will be written to in the transaction must be declared with the write or exclusive attribute or it will fail, whereas non-declared collections from which is solely read will be added lazily.

      • an optional numeric value that can be used to set a timeout in seconds for waiting on collection locks. This option is only meaningful when using exclusive locks. If not specified, a default value will be used. Setting lockTimeout to 0 will make ArangoDB not time out waiting for a lock.

      • Transaction size limit in bytes.

      • an optional boolean flag that, if set, will force the transaction to write all data to disk before returning.

      Responses
      • If the transaction is running on the server, HTTP 201 will be returned.

      • If the transaction specification is either missing or malformed, the server will respond with HTTP 400.

      • If the transaction specification contains an unknown collection, the server will respond with HTTP 404.

      Examples

      Executing a transaction on a single collection

      curl -X POST --header 'accept: application/json' --data-binary @- --dump - http://localhost:8529/_api/transaction/begin
      {
        "collections": {
          "write": "products"
        }
      }
      Show output

      Referring to a non-existing collection

      curl -X POST --header 'accept: application/json' --data-binary @- --dump - http://localhost:8529/_api/transaction/begin
      {
        "collections": {
          "read": "products"
        }
      }
      Show output

      Get the status of a Stream Transaction

      get /_api/transaction/{transaction-id}

      The result is an object describing the status of the transaction. It has at least the following attributes:

      • id: the identifier of the transaction

      • status: the status of the transaction. One of “running”, “committed” or “aborted”.

      Path Parameters
      • The transaction identifier.

      Query Parameters
        HTTP Headers
          Responses
          • If the transaction is fully executed and committed on the server, HTTP 200 will be returned.

          • If the transaction identifier specified is either missing or malformed, the server will respond with HTTP 400.

          • If the transaction was not found with the specified identifier, the server will respond with HTTP 404.

          Examples

          Get transaction status

          curl --header 'accept: application/json' --dump - http://localhost:8529/_api/transaction/71387
          Show output

          Commit a Stream Transaction

          put /_api/transaction/{transaction-id}

          Commit a running server-side transaction. Committing is an idempotent operation. It is not an error to commit a transaction more than once.

          If the transaction can be committed, HTTP 200 will be returned. The returned JSON object has the following properties:

          • error: boolean flag to indicate if an error occurred (false in this case)

          • code: the HTTP status code

          • result: result containing

            • id: the identifier of the transaction
            • status: containing the string ‘committed’

          If the transaction cannot be found, committing is not allowed or the transaction was aborted, the server will respond with HTTP 400, HTTP 404 or HTTP 409.

          The body of the response will then contain a JSON object with additional error details. The object has the following attributes:

          • error: boolean flag to indicate that an error occurred (true in this case)

          • code: the HTTP status code

          • errorNum: the server error number

          • errorMessage: a descriptive error message

          Path Parameters
          • The transaction identifier,

          Query Parameters
            HTTP Headers
              Responses
              • If the transaction was committed, HTTP 200 will be returned.

              • If the transaction cannot be committed, the server will respond with HTTP 400.

              • If the transaction was not found, the server will respond with HTTP 404.

              • If the transaction was already aborted, the server will respond with HTTP 409.

              Examples

              Committing a transaction:

              curl -X PUT --header 'accept: application/json' --dump - http://localhost:8529/_api/transaction/71394
              Show output

              Abort a Stream Transaction

              delete /_api/transaction/{transaction-id}

              Abort a running server-side transaction. Aborting is an idempotent operation. It is not an error to abort a transaction more than once.

              If the transaction can be aborted, HTTP 200 will be returned. The returned JSON object has the following properties:

              • error: boolean flag to indicate if an error occurred (false in this case)

              • code: the HTTP status code

              • result: result containing

                • id: the identifier of the transaction
                • status: containing the string ‘aborted’

              If the transaction cannot be found, aborting is not allowed or the transaction was already committed, the server will respond with HTTP 400, HTTP 404 or HTTP 409.

              The body of the response will then contain a JSON object with additional error details. The object has the following attributes:

              • error: boolean flag to indicate that an error occurred (true in this case)

              • code: the HTTP status code

              • errorNum: the server error number

              • errorMessage: a descriptive error message

              Path Parameters
              • The transaction identifier,

              Query Parameters
                HTTP Headers
                  Responses
                  • If the transaction was aborted, HTTP 200 will be returned.

                  • If the transaction cannot be aborted, the server will respond with HTTP 400.

                  • If the transaction was not found, the server will respond with HTTP 404.

                  • If the transaction was already committed, the server will respond with HTTP 409.

                  Examples

                  Aborting a transaction:

                  curl -X DELETE --header 'accept: application/json' --dump - http://localhost:8529/_api/transaction/71401
                  Show output

                  List the running Stream Transactions

                  get /_api/transaction

                  The result is an object with the transactions attribute, which contains an array of transactions. In a cluster the array will contain the transactions from all Coordinators.

                  Each array entry contains an object with the following attributes:

                  • id: the transaction’s id
                  • state: the transaction’s status
                  Responses
                  • If the list of transactions can be retrieved successfully, HTTP 200 will be returned.

                  Examples

                  Get currently running transactions

                  curl --header 'accept: application/json' --dump - http://localhost:8529/_api/transaction
                  Show output