---

Then the next concepts to consider are all about the program running your actual API (e.g. Uvicorn).

## Program and Process

We will talk a lot about the running "**process**", so it's useful to have clarity about what it means, and what's the difference with the word "**program**".

### What is a Program

The word **program** is commonly used to describe many things:

now returns 0 instead of 1, which may affect programs that
poll the length to decide whether a receive on the timer channel
will succeed.
Such code should use a non-blocking receive instead.

These new behaviors are only enabled when the main Go program
is in a module with a `go.mod` `go` line using Go 1.23.0 or later.
When Go 1.23 builds older programs, the old behaviors remain in effect.

(discussed below).

When preparing any change that is permitted by Go 1 compatibility
but may nonetheless break some existing programs,
we first engineer the change to keep as many existing programs working as possible.
For the remaining programs,
we define a new GODEBUG setting that
allows individual programs to opt back in to the old behavior.
A GODEBUG setting may not be added if doing so is infeasible,

* the data from the client to be sent through the network
* the data sent by your program to be received by the client through the network
* the contents of a file in the disk to be read by the system and given to your program
* the contents your program gave to the system to be written to disk
* a remote API operation
* a database operation to finish
* a database query to return the results

  b) in the case of each subsequent Contributor:
     i) changes to the Program, and
     ii) additions to the Program;
  where such changes and/or additions to the Program originate from
  and are Distributed by that particular Contributor. A Contribution
  "originates" from a Contributor if it was added to the Program by
  such Contributor itself or anyone acting on such Contributor's behalf.

## Server Machine and Server Program

There's a small detail about names to keep in mind. 💡

The word "**server**" is commonly used to refer to both the remote/cloud computer (the physical or virtual machine) and also the program that is running on that machine (e.g. Uvicorn).

You can also create an environment variable only for a specific program invocation, that is only available to that program, and only for its duration.

To do that, create it right before the program itself, on the same line:

<div class="termy">

```console
// Create an env var MY_NAME in line for this program call
$ MY_NAME="Wade Wilson" python main.py

// Now it can read the environment variable

<font color="#4E9A06">INFO</font>:     Waiting for application startup.
<font color="#4E9A06">INFO</font>:     Application startup complete.
```

</div>

That command line program called `fastapi` is **FastAPI CLI**.

FastAPI CLI takes the path to your Python program and automatically detects the variable with the FastAPI (commonly named `app`) and how to import it, and then serves it.

For production you would use `fastapi run` instead. 🚀

* **Coroutines**

## Asenkron kod

Asenkron kod programlama dilinin 💬 bilgisayara / programa 🤖 kodun bir noktasında, *başka bir kodun* bir yerde bitmesini 🤖 beklemesi gerektiğini söylemenin bir yoludur. Bu *başka koda* "slow-file" denir 📝.

Böylece, bu süreçte bilgisayar "slow-file" 📝 tamamlanırken gidip başka işler yapabilir.

            param("env.PERFORMANCE_DB_PASSWORD_TCAGENT", "%performance.db.password.tcagent%")
            when (os) {
                Os.WINDOWS -> param("env.PATH", "%env.PATH%;C:/Program Files/7-zip")
                else -> param("env.PATH", "%env.PATH%:/opt/swift/4.2.3/usr/bin:/opt/swift/4.2.4-RELEASE-ubuntu18.04/usr/bin")
            }
        }
        failureConditions {