Types reference

Beta

Python functions are currently in a beta state and may not be available on all enrollments.

Below is the full list of currently supported functions API types, their corresponding Python types, and whether that type can be declared using its corresponding Python type instead of the functions API type:

Functions API type	Can declare as Python type?	Corresponding Python type
Array	Yes	list
Binary	Yes	bytes
Boolean	Yes	bool
Byte	No	int*
Date	Yes	datetime.date
Decimal	Yes	decimal.Decimal
Double	No	float*
Float	Yes	float
Integer	Yes	int
Long	No	int*
Map	Yes	dict
Set	Yes	set
Short	No	int*
String	Yes	str
Timestamp	Yes	datetime.datetime
Structs / custom types	Yes	dataclass.dataclass (Example)

Although both Integer and Long correspond to the Python type int, any fields marked as int directly in your function signature will be registered with type Integer. Therefore, we instead recommend using either the Integer or Long types from the API to register numerical data types. Similar guidelines apply to Float and Double; if the Python type float is directly in your function signature, it will be registered as Float by default.

Another example function with inputs is shown below:

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from functions.api import function, Long, String, Timestamp

@function
def get_end_day_of_week(start_time: Timestamp, elapsed_millis: Long) -> String:
   # function logic here
   pass

As shown in the above types table, this function could also be declared using only built-in Python types:

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from functions.api import function
from datetime import datetime

@function
def get_end_day_of_week(start_time: datetime, elapsed_millis: int) -> str:
   # function logic here
   pass

Additionally, you could use a combination of built-in and API types:

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from functions.api import function, Long, String
from datetime import datetime

@function
def get_end_day_of_week(start_time: datetime, elapsed_millis: Long) -> String:
   # function logic here
   pass

Custom types and structs

Custom Python classes composed of other supported types can also be used in Function signatures. The API package does not have an explicit Custom type; instead, custom types are declared as user-defined Python classes.

To be a valid custom type, the class must adhere to the following:

The class must have type annotations on all of its fields.
The field types must be supported types; either the primitive API types or native Python types (as defined in the table above) may be used.
The __init__ method must accept only named arguments with the same names and type annotations as the fields.

The dataclasses.dataclass ↗ decorator can be used to automatically generate an __init__ method that conforms with these requirements.

Example custom type using `dataclasses.dataclass`

Here is an example using the dataclasses.dataclass:

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from dataclasses import dataclass
from functions.api import Float, Integer, String, function

@dataclass
class InventoryItem:
"""Class for keeping track of an item in inventory."""
    name: String
    unit_price: Float
    quantity_on_hand: Integer = 0

    def total_cost(self) -> Float:
        return self.unit_price * self.quantity_on_hand

@function
def custom_type_with_init_from_decorator(inventory_item: InventoryItem) -> Float:
    return inventory_item.total_cost()

Example custom type using API types (without `dataclass.dataclass`)

Here is an example without dataclass.dataclass using API types:

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from functions.api import function, String, Timestamp

class Event:
    timestamp: Timestamp
    message: String

    def __init__(
        self,
        timestamp: Timestamp,
        message: String
     ):
        self.timestamp = timestamp
        self.message = message

@function
def get_event_message(event: Event) -> String:
    return event.message

Next steps

Learn how to set up a Python functions repository, or learn more about using Python functions in Pipeline Builder or Workshop.

permalinkTypes reference

permalinkCustom types and structs

permalinkExample custom type using dataclasses.dataclass

permalinkExample custom type using API types (without dataclass.dataclass)

permalinkNext steps

Types reference

Custom types and structs

Example custom type using `dataclasses.dataclass`

Example custom type using API types (without `dataclass.dataclass`)

Next steps