singer_sdk.Tap

class singer_sdk.Tap

Bases: BaseSingerWriter

Abstract base class for taps.

The Tap class governs configuration, validation, and stream discovery for tap plugins.

message_writer_class

alias of SimpleSingerWriter

classmethod append_builtin_config(config_jsonschema)

Appends built-in config to config_jsonschema if not already set.

To customize or disable this behavior, developers may either override this class method or override the capabilities property to disabled any unwanted built-in capabilities.

For all except very advanced use cases, we recommend leaving these implementations “as-is”, since this provides the most choice to users and is the most “future proof” in terms of taking advantage of built-in capabilities which may be added in the future.

Parameters:

config_jsonschema (dict) – [description]

Return type:

None

classmethod cb_discover(ctx, param, value)

CLI callback to run the tap in discovery mode.

Parameters:

• ctx (Context) – Click context.

• param (Option) – Click option.

• value (bool) – Whether to run in discovery mode.

Return type:

None

classmethod cb_test(ctx, param, value)

CLI callback to run the tap in test mode.

Parameters:

• ctx (Context) – Click context.

• param (Option) – Click option.

• value (bool) – Whether to run in test mode.

Return type:

None

classmethod cb_version(ctx, param, value)

CLI callback to print the plugin version and exit.

Parameters:

• ctx (Context) – Click context.

• param (Option) – Click parameter.

• value (bool) – Boolean indicating whether to print the version.

Return type:

None

classmethod get_plugin_version()

Return the package version number.

Returns:

The package version number.

Return type:

str

classmethod get_sdk_version()

Return the package version number.

Returns:

The package version number.

Return type:

str

classmethod get_singer_command()

Execute standard CLI handler for taps.

Returns:

A click.Command object.

Return type:

Command

classmethod get_supported_python_versions()

Return the supported Python versions.

Returns:

A list of supported Python versions.

Return type:

list[str] | None

classmethod instantiate_processor(instance, default_cls)

Instantiate a processor instance.

Parameters:

• instance (_T | None) – The instance to instantiate.

• default_cls (type[_T]) – The default class to instantiate.

Returns:

The instantiated processor instance.

Return type:

_T

classmethod invoke(*, about=False, about_format=None, config=(), state=None, catalog=None)

Invoke the tap’s command line interface.

Parameters:

• about (bool) – Display package metadata and settings.

• about_format (str | None) – Specify output style for –about.

• config (tuple[str, ...]) – Configuration file location or ‘ENV’ to use environment variables. Accepts multiple inputs as a tuple.

• catalog (Path | None) – Use a Singer catalog file with the tap.”,

• state (Path | None) – Use a bookmarks file for incremental replication.

Return type:

None

classmethod print_about(output_format=None)

Print capabilities and other tap metadata.

Parameters:

output_format (str | None) – Render option for the plugin information.

Return type:

None

classmethod print_version(print_fn=<built-in function print>)

Print help text for the tap.

Parameters:

print_fn (Callable[[Any], None]) – A function to use to display the plugin version. Defaults to print().

Return type:

None

static config_from_cli_args(*args)

Parse CLI arguments into a config dictionary.

Parameters:

args (str) – CLI arguments.

Raises:

FileNotFoundError – If the config file does not exist.

Returns:

A tuple containing the config dictionary and a boolean indicating whether the config file was found.

Return type:

tuple[list[Path], bool]

__init__(*, config=None, catalog=None, state=None, parse_env_config=False, validate_config=True, setup_mapper=True, message_writer=None)

Initialize the tap.

Parameters:

• config (dict | PurePath | str | list[PurePath | str] | None) – Tap configuration. Can be a dictionary, a single path to a configuration file, or a list of paths to multiple configuration files.

• catalog (PurePath | str | dict | Catalog | None) – Tap catalog. Can be a dictionary or a path to the catalog file.

• state (PurePath | str | dict | None) – Tap state. Can be dictionary or a path to the state file.

• parse_env_config (bool) – Whether to look for configuration values in environment variables.

• validate_config (bool) – True to require validation of config settings.

• setup_mapper (bool) – True to initialize the plugin mapper.

• message_writer (GenericSingerWriter | None) – The class class to use for writing Singer messages.

Return type:

None

discover_streams()

Initialize all available streams and return them as a list.

Returns:

List of discovered Stream objects.

Raises:

NotImplementedError – If the tap implementation does not override this method.

Return type:

t.Sequence[Stream]

load_state(state)

Merge or initialize stream state with the provided state dictionary input.

Override this method to perform validation and backwards-compatibility patches on self.state. If overriding, we recommend first running super().load_state(state) to ensure compatibility with the SDK.

Parameters:

state (dict[str, Any]) – Initialize the tap’s state with this value.

Raises:

ValueError – If the tap’s own state is None, meaning it has not been initialized.

Return type:

None

final load_streams()

Load streams from discovery and initialize DAG.

Return the output of self.discover_streams() to enumerate discovered streams.

Returns:

A list of discovered streams, ordered by name.

Return type:

list[Stream]

final run_connection_test()

Run connection test, aborting each stream after 1 record.

Returns:

True if the test succeeded.

Return type:

bool

run_discovery()

Write the catalog json to STDOUT and return as a string.

Returns:

The catalog as a string of JSON.

Return type:

str

final run_sync_dry_run(dry_run_record_limit=1, streams=None)

Run connection test.

Exceptions of type MaxRecordsLimitException and PartialSyncSuccessException will be ignored.

Parameters:

• dry_run_record_limit (int | None) – The max number of records to sync per stream object.

• streams (t.Iterable[Stream] | None) – The streams to test. If omitted, all streams will be tested.

Returns:

True if the test succeeded.

Return type:

bool

setup_mapper()

Initialize the plugin mapper for this tap.

Return type:

None

final sync_all()

Sync all streams.

Return type:

None

write_message(message)

Write a message to the tap’s message writer.

Parameters:

message (Any)

Return type:

None

final write_schemas()

Write a SCHEMA message for all known streams to STDOUT.

Return type:

None

property catalog: Catalog

Get the tap’s working catalog.

Returns:

A Singer catalog object.

property catalog_dict: dict

Get catalog dictionary.

Returns:

The tap’s catalog as a dict

property catalog_json_text: str

Get catalog JSON.

Returns:

The tap’s catalog as formatted JSON text.

property config: Mapping[str, Any]

Get config.

Returns:

A frozen (read-only) config dictionary map.

dynamic_catalog: bool = False

Whether the tap’s catalog is dynamic. Set to True if the catalog is generated dynamically (e.g. by querying a database’s system tables).

property initialized_at: int

Start time of the plugin.

Returns:

The start time of the plugin.

property input_catalog: Catalog | None

Get the catalog passed to the tap.

Returns:

Catalog dictionary input, or None if not provided.

property mapper: PluginMapper

Plugin mapper for this tap.

Returns:

A PluginMapper object.

Raises:

MapperNotInitialized – If the mapper has not been initialized.

name: str

The executable name of the tap or target plugin. e.g. tap-foo

package_name: str | None = None

The package name of the plugin. e.g meltanolabs-tap-foo

property state: dict

Get tap state.

Returns:

The tap’s state dictionary

Raises:

RuntimeError – If state has not been initialized.

property streams: dict[str, Stream]

Get streams discovered or catalogued for this tap.

Results will be cached after first execution.

Returns:

A mapping of names to streams, using discovery or a provided catalog.