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Submodule cluster Lua API

Submodule cluster.lua is a part of GraphQL API module provided functions specific to cluster application architecture. This particular implementation was made for Tarantool Cartridge Application (requires: Cartridge, VShard and DDL modules), for any custom application architecture, for example for so called pure-Tarantool applications most functions of this module may need to be overridden to comply it.

lua API

get_servers()

cluster.get_servers() - method to get connections to all cluster instances,

returns:

  • [1] (table) - array of maps with the following structure:
    • alias (string) - alias of instance
    • conn (table) - conn object. For more details see: net_box module
  • [2] (table) - array of errors if any of need instances is not available.

get_masters()

cluster.get_masters() - method to get connections to active master instances of all cluster replicasets,

returns:

  • [1] (table) - array of maps with the following structure:
    • alias (string) - alias of instance
    • conn (table) - conn object. For more details see: net_box module
  • [2] (table) - array of errors if any of need instances is not available.

get_storages_instances()

cluster.get_storages_instances(mode, prefer_replica, balance) - method to get connections to get one instance from of all storage replicasets according to desired policy,

where:

  • mode (string) - optional, have to be 'write' for replicaset masters (default) or 'read' for replicas if available;
  • prefer_replica (boolean) - optional, if true then the preferred target is one of the replicas, false by default;
  • balance (boolean) - use replica according to vshard load balancing policy;

returns:

  • [1] (table) - array of maps with the following structure:
    • alias (string) - alias of instance
    • conn (table) - conn object. For more details see: net_box module
  • [2] (table) - array of errors if any of need instances is not available.

get_self_alias()

cluster.get_self_alias() - method to get instance alias this function called on,

returns:

  • [1] (string) - name of instance.

get_self_uri()

cluster.get_self_uri() - method to get instance URI this function called on,

returns:

  • [1] (string) - URI (IP:port or FQDN:port) of instance.

get_replicasets()

cluster.get_replicasets() - method to get all cluster replicasets alias names,

returns:

  • [1] (table) - array of strings - cluster replicasets alias names.

get_replicaset_instances()

cluster.get_replicaset_instances(replicaset) - method to get all replicaset instances alias names,

where:

  • replicaset (table) - alias name of replicaset;

returns:

  • [1] (table) - map with cluster replicaset instances, has the following format:
    • alias (string) - instance alias name;
    • uri (string) - instance connection string;
    • status (string) - server status.

get_instances()

cluster.get_instances() - method to get all cluster replicasets alias names,

returns:

  • [1] (table) - map with cluster replicaset instances, has the following format:
    • alias (string) - instance alias name;
    • uri (string) - instance connection string;
    • status (string) - server status.

get_candidates()

cluster.get_candidates(role) - method to get all cluster instances with the provided role,

where:

  • role (string) - mandatory, role name,

returns:

  • [1] (table) - map with cluster replicaset instances, has the following format:
    • alias (string) - instance alias name;
    • uri (string) - instance connection string;
    • status (string) - server status.

get_servers_by_list()

cluster.get_servers_by_list() - method to get servers objects by provided list of instances alias names,

returns:

  • [1] (table) - array of conn objects to all servers. For more details see: net_box module

  • [2] (table) - array of errors if some instances is not available.

get_existing_spaces()

cluster.get_existing_spaces() - method to get list of existing spaces,

returns:

  • [1] (table) - array of strings of existing non-system spaces on instance this function called on.

is_space_exists()

cluster.is_space_exists(space) - method to check if the desired space is exists,

where:

  • space (string) - name of space to be checked;

returns:

  • [1] (boolean) - true if space exists, false - if not.

get_schema()

cluster.get_schema() - method to get database schema (ddl.get_schema() wrapper),

returns:

check_schema()

cluster.check_schema() - method to get database schema (ddl.check_schema() wrapper),

returns:

  • [1] (boolean) - true if no error, otherwise return nil;
  • [2] (error) - error object.

For additional info see ddl.check_schema().

set_schema()

cluster.set_schema() - method to get database schema (ddl.set_schema() wrapper),

returns:

  • [1] (boolean) - true if no error, otherwise return nil;
  • [2] (error) - error object.

For additional info see ddl.set_schema().