Glossary¶

Key terms for this project.

1. Streaming Concepts¶

streaming data¶

Data that is generated and processed continuously over time, one event at a time, rather than collected and analyzed all at once. A sale completing, a sensor reading, a page view - each is a streaming event.

data in motion¶

Another way to describe streaming data. The data is moving from where it is created to where it is needed, rather than sitting in a file waiting to be read.

producer¶

A program that generates and sends messages into a stream. In this project, the producer simulates online sales arriving one at a time.

consumer¶

A program that reads and processes messages from a stream. Producers create data. Consumers use it. Producers and consumers can run at the same time.

message / event¶

One unit of data in a stream. In this project, one message provides information about one sale.

generator¶

A Python function that uses yield to produce one value at a time instead of computing and returning everything at once. Generators are a natural fit for streaming because real data also arrives one item at a time.

def generate_messages(count: int):
    for i in range(count):
        yield i + 1   # produces one value, then pauses

2. Python Basics¶

variable¶

A name that holds a value.

course_name: str = "Streaming Data"

constant¶

A variable whose value does not change while the program runs. Named in ALL_CAPS by convention.

MESSAGE_COUNT: Final[int] = 10

type hint¶

An annotation that declares what type of data a variable holds. Helps editors catch errors early. Does not change how the code runs.

amount: float = 81.87
products: list[str] = ["Shoes", "Mat"]

f-string¶

A string that embeds variable values directly into text.

region: str = "North"
LOG.info(f"Sale from region: {region}")

logging¶

Recording messages about what a program is doing while it runs. Preferred over print() in professional projects.

LOG.info("Starting producer.")
LOG.warning("No data received.")

main function¶

The starting point of a script. Called by the conditional execution guard.

conditional execution guard¶

The standard block at the bottom of every script. Ensures main() only runs when the file is executed directly.

if __name__ == "__main__":
    main()