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index 9e02400e13ea597d9201d0a0577c47e9daefa11e..7aae68dde622a0ebe7835c796a46c216838b7de8 100644 (file)
* message body depends on the message type. Both, the message type and length
* are stored in an unsigned 32bit integer in network byte-order.
*
+ * Any strings in the message body may not include a zero byte.
+ *
* 1 3 4 6
* 0 6 2 8 4
* +-------------------------------+-------------------------------+
/* status codes returned to a client */
typedef enum {
/*
- * CONNECTION_OK:
- * Indicates that a command was successful. The message body will contain
- * the result of the command (if any) encoded as a JSON string.
+ * Generic status and log messages.
+ */
+
+ /*
+ * SDB_CONNECTION_OK:
+ * Indicates that a command was successful. The message body will usually
+ * be empty but may contain a string providing unformatted information
+ * providing more details.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | OK | len(msg) |
+ * +---------------+---------------+
+ * | optional status message ... |
*/
- CONNECTION_OK = 0,
+ SDB_CONNECTION_OK = 0,
/*
- * CONNECTION_ERROR:
+ * SDB_CONNECTION_ERROR:
* Indicates that a command has failed. The message body will contain a
* string describing the error.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | ERROR | len(msg) |
+ * +---------------+---------------+
+ * | error message ... |
*/
- CONNECTION_ERROR,
+ SDB_CONNECTION_ERROR,
/*
- * CONNECTION_LOG:
+ * SDB_CONNECTION_LOG:
* Indicates an asynchronous log message. The message body will contain
- * the message string providing informational or warning logs. Log
- * messages may be sent to the client any time.
+ * the log priority (see utils/error.h) and message. Log messages may be
+ * sent to the client any time.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | LOG | length |
+ * +---------------+---------------+
+ * | log priority | log message |
+ * +---------------+ |
+ * | ... |
+ */
+ SDB_CONNECTION_LOG,
+
+ /*
+ * Query-result specific messages.
*/
- CONNECTION_LOG,
+
+ /*
+ * SDB_CONNECTION_DATA:
+ * Indicates that a data query was successful. The message body will
+ * contain the type of the data and the result encoded as a JSON string.
+ * The type is the same as the command code of the respective command (see
+ * below) and is stored as an unsigned 32bit integer in network
+ * byte-order. The result may be empty (but the type is still included) if
+ * the query did not return any result. The type and the result message
+ * are empty on empty commands.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | DATA | length |
+ * +---------------+---------------+
+ * | result type | result ... |
+ * +---------------+ |
+ * | ... |
+ */
+ SDB_CONNECTION_DATA = 100,
} sdb_conn_status_t;
/* accepted commands / state of the connection */
typedef enum {
/*
- * CONNECTION_IDLE:
+ * SDB_CONNECTION_IDLE:
* This is an internal state used for idle connections.
*/
- CONNECTION_IDLE = 0,
+ SDB_CONNECTION_IDLE = 0,
/*
- * CONNECTION_PING:
+ * SDB_CONNECTION_PING:
* Check if the current connection is still alive. The server will reply
- * with CONNECTION_OK if it was able to handle the command.
+ * with SDB_CONNECTION_OK and an empty message body if it was able to
+ * handle the command.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | PING | 0 |
+ * +---------------+---------------+
*/
- CONNECTION_PING,
+ SDB_CONNECTION_PING,
/*
- * CONNECTION_STARTUP:
+ * SDB_CONNECTION_STARTUP:
* Setup of a client connection. The message body shall include the
* username of the user contacting the server. The server may then send
* further requests to the client for authentication (not implemented
* yet). Once the setup and authentication was successful, the server
- * replies with CONNECTION_OK. Further information may be requested from
- * the server using special messages specific to the authentication
+ * replies with SDB_CONNECTION_OK. Further information may be requested
+ * from the server using special messages specific to the authentication
* method. The server does not send any asynchronous messages before
* startup is complete.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | STARTUP | len(username) |
+ * +---------------+---------------+
+ * | username ... |
*/
- CONNECTION_STARTUP,
+ SDB_CONNECTION_STARTUP,
/*
- * Querying the server.
+ * Querying the server. On success, the server replies with
+ * SDB_CONNECTION_DATA.
+ *
+ * The command codes listed here are used, both, for sending a query to
+ * the server and to indicate the response type from a query in a DATA
+ * message.
*/
/*
- * CONNECTION_QUERY:
+ * SDB_CONNECTION_QUERY:
* Execute a query in the server. The message body shall include a single
* query command as a text string. Multiple commands are ignored by the
- * server entirely.
+ * server entirely to protect against injection attacks.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | QUERY | len(query) |
+ * +---------------+---------------+
+ * | query string ... |
*/
- CONNECTION_QUERY,
+ SDB_CONNECTION_QUERY,
/*
- * CONNECTION_FETCH:
+ * SDB_CONNECTION_FETCH:
* Execute the 'FETCH' command in the server. The message body shall
- * include the hostname of the host to be retrieved.
+ * include the type and the identifier of the object to be retrieved.
+ * Hosts are identified by their name. Other types are not supported yet.
+ * The type is encoded as a 32bit integer in network byte-order.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | FETCH | length |
+ * +---------------+---------------+
+ * | object type | identifier |
+ * +---------------+ |
+ * | ... |
*/
- CONNECTION_FETCH,
+ SDB_CONNECTION_FETCH,
/*
- * CONNECTION_LIST:
- * Execute the 'LIST' command in the server.
+ * SDB_CONNECTION_LIST:
+ * Execute the 'LIST' command in the server. The message body may include
+ * the type of the objects to be listed, encoded as a 32bit integer in
+ * network byte-order. The response includes all hosts and the respective
+ * child objects. By default, all hosts are listed.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | LIST | length |
+ * +---------------+---------------+
+ * | [object type] |
+ * +---------------+
*/
- CONNECTION_LIST,
+ SDB_CONNECTION_LIST,
/*
- * CONNECTION_LOOKUP:
+ * SDB_CONNECTION_LOOKUP:
* Execute the 'LOOKUP' command in the server. The message body shall
- * include the conditional expression of the 'MATCHING' clause.
+ * include the type of the objects to look up and a string representing
+ * the conditional expression of the 'MATCHING' clause. The type is
+ * encoded as a 32bit integer in network byte-order.
+ *
+ * 0 32 64
+ * +---------------+---------------+
+ * | LOOKUP | length |
+ * +---------------+---------------+
+ * | object type | matching |
+ * +---------------+ |
+ * | clause ... |
*/
- CONNECTION_LOOKUP,
+ SDB_CONNECTION_LOOKUP,
/*
- * CONNECTION_TIMESERIES:
+ * SDB_CONNECTION_TIMESERIES:
* Execute the 'TIMESERIES' command in the server. This command is not yet
- * supported on the wire. Use CONNECTION_QUERY instead.
+ * supported on the wire. Use SDB_CONNECTION_QUERY instead.
*/
- CONNECTION_TIMESERIES,
+ SDB_CONNECTION_TIMESERIES,
/*
* Command subcomponents.
*/
/*
- * CONNECTION_EXPR:
+ * SDB_CONNECTION_MATCHER:
+ * A parsed matcher. Only used internally.
+ */
+ SDB_CONNECTION_MATCHER = 100,
+
+ /*
+ * SDB_CONNECTION_EXPR:
* A parsed expression. Only used internally.
*/
- CONNECTION_EXPR,
+ SDB_CONNECTION_EXPR,
} sdb_conn_state_t;
#ifdef __cplusplus