## Build a Docker Image for FastAPI { #build-a-docker-image-for-fastapi }

Okay, let's build something now! 🚀

I'll show you how to build a **Docker image** for FastAPI **from scratch**, based on the **official Python** image.

This is what you would want to do in **most cases**, for example:

* Using **Kubernetes** or similar tools
* When running on a **Raspberry Pi**

In the next chapter about [FastAPI in Containers - Docker](docker.md){.internal-link target=_blank} I'll explain some strategies you could use to handle the other **deployment concepts**.

I'll show you how to **build your own image from scratch** to run a single Uvicorn process. It is a simple process and is probably what you would want to do when using a distributed container management system like **Kubernetes**.

## Recap { #recap }

io-webhook-python-fastapi title: Build a Secure Twilio Webhook with Python and FastAPI - author: Sebastián Ramírez (tiangolo) author_link: https://x.com/tiangolo link: https://dev.to/tiangolo/build-a-web-api-from-scratch-with-fastapi-the-workshop-2ehe title: Build a web API from scratch with FastAPI - the workshop - author: Paul Sec author_link: https://x.com/PaulWebSec link: https://paulsec.github.io/posts/fastapi_plus_zeit_serverless_fu/ title: FastAPI + Zeit.co = 🚀 - author: cuongld2 author_link:...

{* ../../docs_src/python_types/tutorial001.py hl[2] *}

### Edit it { #edit-it }

It's a very simple program.

But now imagine that you were writing it from scratch.

At some point you would have started the definition of the function, you had the parameters ready...

But then you have to call "that method that converts the first letter to upper case".

        * [FastAPI + Zeit.co = 🚀](https://paulsec.github.io/posts/fastapi_plus_zeit_serverless_fu/) by [Paul Sec](https://x.com/PaulWebSec).
        * [Build a web API from scratch with FastAPI - the workshop](https://dev.to/tiangolo/build-a-web-api-from-scratch-with-fastapi-the-workshop-2ehe) by [Sebastián Ramírez (tiangolo)](https://x.com/tiangolo).

                                tree.release();
                            } catch (Exception e) {
                                log.debug("Error during emergency tree cleanup", e);
                            }
                        }
                        this.trees.clear();
                    } catch (Exception e) {
                        log.debug("Error clearing trees during emergency cleanup", e);

        this.connectionState.set(2); // connected

        try {
            validateNegotiation(transport, sess);
        } catch (final CIFSException se) {
            try {
                transport.disconnect(true);
            } catch (final IOException e) {
                log.warn("Failed to disconnect transport", e);
                se.addSuppressed(e);
            }
            throw se;

                try {
                    trans.ensureConnected();
                } catch (final IOException e) {
                    removeTransport(trans);
                    throw e;
                }
                return trans.acquire();
            } catch (final IOException e) {
                final String hostAddress = addr.getHostAddress();

                        successCount.incrementAndGet();

                        // Small delay to increase chance of race conditions
                        Thread.yield();
                    }
                } catch (Exception e) {
                    exceptions.add(e);
                } finally {
                    endLatch.countDown();
                }
            });
        }

        // Start all threads simultaneously

        generator.setCommandList(Collections.singletonList("echo test"));
        try {
            generator.generate("test_id", null);
            fail("Should throw exception for null output file");
        } catch (final Exception e) {
            assertTrue(true);
        }
    }

    public void test_generate_thumbnailId_null() throws Exception {
        final File outputFile = File.createTempFile("command_generator", ".out");