REST Endpoint

The REST endpoint allows user to connect to SQL Gateway with REST API.

Overview of SQL Processing

Open Session

When the client connects to the SQL Gateway, the SQL Gateway creates a Session as the context to store the users-specified information during the interactions between the client and SQL Gateway. After the creation of the Session, the SQL Gateway server returns an identifier named SessionHandle for later interactions.

Submit SQL

After the registration of the Session, the client can submit the SQL to the SQL Gateway server. When submitting the SQL, the SQL is translated to an Operation and an identifier named OperationHandle is returned for fetch results later. The Operation has its lifecycle, the client is able to cancel the execution of the Operation or close the Operation to release the resources used by the Operation.

Fetch Results

With the OperationHandle, the client can fetch the results from the Operation. If the Operation is ready, the SQL Gateway will return a batch of the data with the corresponding schema and a URI that is used to fetch the next batch of the data. When all results have been fetched, the SQL Gateway will fill the resultType in the response with value EOS and the URI to the next batch of the data is null.

Endpoint Options

Key	Default	Type	Description
sql-gateway.endpoint.rest.address	(none)	String	The address that should be used by clients to connect to the sql gateway server.
sql-gateway.endpoint.rest.bind-address	(none)	String	The address that the sql gateway server binds itself.
sql-gateway.endpoint.rest.bind-port	“8083”	String	The port that the sql gateway server binds itself. Accepts a list of ports (“50100,50101”), ranges (“50100-50200”) or a combination of both. It is recommended to set a range of ports to avoid collisions when multiple sql gateway servers are running on the same machine.
sql-gateway.endpoint.rest.port	8083	Integer	The port that the client connects to. If bind-port has not been specified, then the sql gateway server will bind to this port.

REST API

[OpenAPI specification](http://nightlies.apache.org/flink/flink-docs-release-1.16/docs/dev/table/sql-gateway/rest/

/nightlies.apache.org/flink/flink-docs-release-1.16/generated/rest_v1_sql_gateway.yml )

The OpenAPI specification is still experimental.

API reference

/api_versions
Verb: `GET`	Response code: `200 OK`
Get the current available versions for the Rest Endpoint. The client can choose one of the return version as the protocol for later communicate.
Request ▾ `{}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:util:GetApiVersionResponseBody”,` `“properties” : {` `“versions” : {` `“type” : “array”,` `“items” : {` `“type” : “string”` `}` `}` `}` `}`

/info
Verb: `GET`	Response code: `200 OK`
Get meta data for this cluster.
Request ▾ `{}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:util:GetInfoResponseBody”,` `“properties” : {` `“productName” : {` `“type” : “string”` `},` `“version” : {` `“type” : “string”` `}` `}` `}`

/sessions
Verb: `POST`	Response code: `200 OK`
Opens a new session with specific properties. Specific properties can be given for current session which will override the default properties of gateway.
Request ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:session:OpenSessionRequestBody”,` `“properties” : {` `“properties” : {` `“type” : “object”,` `“additionalProperties” : {` `“type” : “string”` `}` `},` `“sessionName” : {` `“type” : “string”` `}` `}` `}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:session:OpenSessionResponseBody”,` `“properties” : {` `“sessionHandle” : {` `“type” : “string”` `}` `}` `}`

/sessions/:session_handle
Verb: `DELETE`	Response code: `200 OK`
Closes the specific session.
Path parameters
`session_handle` - The SessionHandle that identifies a session.
Request ▾ `{}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:session:CloseSessionResponseBody”,` `“properties” : {` `“status” : {` `“type” : “string”` `}` `}` `}`

/sessions/:session_handle
Verb: `GET`	Response code: `200 OK`
Get the session configuration.
Path parameters
`session_handle` - The SessionHandle that identifies a session.
Request ▾ `{}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:session:GetSessionConfigResponseBody”,` `“properties” : {` `“properties” : {` `“type” : “object”,` `“additionalProperties” : {` `“type” : “string”` `}` `}` `}` `}`

/sessions/:session_handle/heartbeat
Verb: `POST`	Response code: `200 OK`
Trigger heartbeat to tell the server that the client is active, and to keep the session alive as long as configured timeout value.
Path parameters
`session_handle` - The SessionHandle that identifies a session.
Request ▾ `{}`
Response ▾ `{}`

/sessions/:session_handle/operations/:operation_handle/cancel
Verb: `POST`	Response code: `200 OK`
Cancel the operation.
Path parameters
`session_handle` - The SessionHandle that identifies a session. `operation_handle` - The OperationHandle that identifies a operation.
Request ▾ `{}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:operation:OperationStatusResponseBody”,` `“properties” : {` `“status” : {` `“type” : “string”` `}` `}` `}`

/sessions/:session_handle/operations/:operation_handle/close
Verb: `DELETE`	Response code: `200 OK`
Close the operation.
Path parameters
`session_handle` - The SessionHandle that identifies a session. `operation_handle` - The OperationHandle that identifies a operation.
Request ▾ `{}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:operation:OperationStatusResponseBody”,` `“properties” : {` `“status” : {` `“type” : “string”` `}` `}` `}`

/sessions/:session_handle/operations/:operation_handle/result/:token
Verb: `GET`	Response code: `200 OK`
Fetch results of Operation.
Path parameters
`session_handle` - The SessionHandle that identifies a session. `operation_handle` - The OperationHandle that identifies a operation. `token` - The OperationHandle that identifies a operation.
Request ▾ `{}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:statement:FetchResultsResponseBody”,` `“properties” : {` `“nextResultUri” : {` `“type” : “string”` `},` `“resultType” : {` `“type” : “string”` `},` `“results” : {` `“type” : “any”` `}` `}` `}`

/sessions/:session_handle/operations/:operation_handle/status
Verb: `GET`	Response code: `200 OK`
Get the status of operation.
Path parameters
`session_handle` - The SessionHandle that identifies a session. `operation_handle` - The OperationHandle that identifies a operation.
Request ▾ `{}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:operation:OperationStatusResponseBody”,` `“properties” : {` `“status” : {` `“type” : “string”` `}` `}` `}`

/sessions/:session_handle/statements
Verb: `POST`	Response code: `200 OK`
Execute a statement.
Path parameters
`session_handle` - The SessionHandle that identifies a session.
Request ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:statement:ExecuteStatementRequestBody”,` `“properties” : {` `“executionConfig” : {` `“type” : “object”,` `“additionalProperties” : {` `“type” : “string”` `}` `},` `“executionTimeout” : {` `“type” : “integer”` `},` `“statement” : {` `“type” : “string”` `}` `}` `}`
Response ▾ `{` `“type” : “object”,` `“id” : “urn:jsonschema:org:apache:flink:table:gateway:rest:message:statement:ExecuteStatementResponseBody”,` `“properties” : {` `“operationHandle” : {` `“type” : “string”` `}` `}` `}`

Data Type Mapping

Currently, REST endpoint uses JSON format to serialize the Table Objects. Please refer JSON format to the mappings.

REST Endpoint

REST Endpoint

Overview of SQL Processing

Open Session

Submit SQL

Fetch Results

Endpoint Options

sql-gateway.endpoint.rest.address

sql-gateway.endpoint.rest.bind-address

sql-gateway.endpoint.rest.bind-port

sql-gateway.endpoint.rest.port

REST API

API reference

/api_versions

/info

/sessions

/sessions/:session_handle

/sessions/:session_handle

/sessions/:session_handle/heartbeat

/sessions/:session_handle/operations/:operation_handle/cancel

/sessions/:session_handle/operations/:operation_handle/close

/sessions/:session_handle/operations/:operation_handle/result/:token

/sessions/:session_handle/operations/:operation_handle/status

/sessions/:session_handle/statements

Data Type Mapping