Update README.md

Author: garyrutland

README.md

@@ -62,9 +62,13 @@ docker images
 
 ---
 
+## 1. The foundation
+
+**Goal:** Get a working container environment running.
+
 ### Create project folder
 
-Create a new folder for your project in a sensible location, for example:
+Create a new folder for your project:
 
 ```shell
 mkdir -p ~/Documents/daemon-labs/docker-aws-lambda
@@ -76,307 +80,41 @@ mkdir -p ~/Documents/daemon-labs/docker-aws-lambda
 ### Open the new folder in your code editor
 
 > [!TIP]
-> If you are using VSCode, we can now do everything from within the code editor.
+> If you are using VSCode, we can now do everything from within the code editor.  
+> You can open the terminal window via Terminal -> New Terminal.
+
+### Create the code subdirectory
 
-### Create `./nodejs` folder
+We keep our application code separate from infrastructure config.
+
+```shell
+mkdir nodejs
+```
 
-### Create `Dockerfile`
+### Create the `Dockerfile`
 
-Add the following content:
+Create the file at `nodejs/Dockerfile` (inside the subdirectory).
 
 ```Dockerfile
 FROM public.ecr.aws/lambda/nodejs:24
 ```
 
 ### Create `docker-compose.yaml`
 
-Add the following content to define your service:
+Create this file in the **root** of your project.
 
 ```yaml
----
 services:
   lambda:
-    build: .
-```
-
-### Initial image check
-
-Run the following command:
-
-```shell
-docker compose build
+    build: ./nodejs
 ```
 
-> [!NOTE]
-> If you now run `docker images`, you'll see a newly created image which should be around 436MB in size.
+### Initialise the container
 
-Run the following command:
+Run this command to start an interactive shell.
 
 ```shell
 docker compose run -it --rm --entrypoint /bin/sh -v ./nodejs:/var/task lambda
 ```
 
-> [!NOTE]
-> This command opens an interactive session with the container.
-
-Run the following command:
-
-```shell
-node --version
-```
-
-> [!NOTE]
-> The output should start with `v22` followed by the latest minor and patch version.
-
-### Initialise project and install dev dependencies
-
-Run the following command:
-
-```shell
-npm init -y
-```
-
-> [!NOTE]
-> Notice how the `nodejs` directory is automatically created on your host machine due to the volume mount.
-
-Run the following command:
-
-```shell
-npm add --save-dev @types/node@22 @types/aws-lambda @tsconfig/recommended typescript
-```
-
-> [!NOTE]
-> Notice this automatically creates a `package-lock.json` file.
-
-### Exit the container
-
-Run the following command:
-
-```shell
-exit
-```
-
-> [!NOTE]
-> We are now done with the interactive container at this stage and no longer need it.
-
-### Create `./nodejs/tsconfig.json`
-
-Create `./nodejs/tsconfig.json` and add the following content to configure the TypeScript compiler:
-
-```json
-{
-  "extends": "@tsconfig/recommended/tsconfig.json",
-  "compilerOptions": {
-    "outDir": "./build"
-  }
-}
-```
-
-> [!NOTE]
-> While you could auto-generate this file, our manual configuration using a recommended preset keeps the file minimal and clean.
-
-### Create source file and scripts
-
-Create `./nodejs/src/index.ts` with the following:
-
-```typescript
-import { Handler } from "aws-lambda";
-
-export const handler: Handler = (event, context) => {
-  console.log("Hello world!");
-  console.log({ event, context });
-};
-```
-
-Add the following to the `scripts` section in your `package.json`:
-
-```json
-"build": "tsc",
-```
-
----
-
-Update the `Dockerfile`
-
-```Dockerfile
-FROM public.ecr.aws/lambda/nodejs:24
-
-HEALTHCHECK --interval=1s --timeout=1s --retries=30 \
-    CMD [ "curl", "-I", "http://localhost:8080" ]
-
-COPY ./nodejs ${LAMBDA_TASK_ROOT}
-
-RUN npm ci && npm run build
-
-CMD [ "build/index.handler" ]
-```
-
-Run `docker compose up --build`
-
-> [!WARNING]
-> This Lambda starts but nothing happens.  
-> **Exit your container by pressing `Ctrl+C`** on your keyboard.
-
-Add a new service to the `docker-compose.yaml` file
-
-```yaml
-curl:
-  image: curlimages/curl
-  depends_on:
-    lambda:
-      condition: service_healthy
-  command:
-    - -s
-    - -d {}
-    - http://lambda:8080/2015-03-31/functions/function/invocations
-```
-
-Run `docker compose up --build`
-
-> [!WARNING]
-> The Lambda and cURL containers start and execute, the cURL container responded with an exit code of 0 but is still hanging.  
-> **Exit your container by pressing `Ctrl+C`** on your keyboard.
-
-Run `docker compose up --build --abort-on-container-exit`
-
-> [!NOTE]
-> The Lambda and cURL containers start and execute, the cURL container responded with an exit code of 0 and both containers shut down.
-
-Add the following environment variables to the `Dockerfile`
-
-```Dockerfile
-ENV AWS_LAMBDA_FUNCTION_MEMORY_SIZE=128
-ENV AWS_LAMBDA_FUNCTION_TIMEOUT=3
-```
-
-> [!TIP]
-> This replicates the default settings of an AWS Lambda.  
-> Without these the Docker image defaults to a memory size of 3008MB and potentially an infinite timeout.
-
-Add the following environment variable to the `Dockerfile`
-
-```Dockerfile
-ENV AWS_LAMBDA_LOG_FORMAT=JSON
-```
-
-> [!TIP]
-> When we executed our Lambda you might have noticed our two logs were printed as plain text.  
-> In fact, the `console.log({ event, context });` didn't actually print out anything useful at all.
-
-### Set up an event
-
-Create an `events` directory
-
-Create a `test.json` file, add the following and save:
-
-```json
-{
-  "test": "test"
-}
-```
-
-### Update the command in `docker-compose.yaml`
-
-Update the command for the cURL container:
-
-```yaml
-command:
-  - -s
-  - -d
-  - ${LAMBDA_INPUT:-{}}
-  - http://lambda:8080/2015-03-31/functions/function/invocations
-```
-
-> [!NOTE]
-> By defining the command like this, by default it will pass in `{}` as the event still.
-
-Add the `events` directory as a volume to the cURL container:
-
-```yaml
-volumes:
-  - ./events:/events:ro
-```
-
-Run `LAMBDA_INPUT=@/events/test.json docker compose up --build --abort-on-container-exit`
-
-> [!TIP]
-> The `@` tells the cURL command that it should include the contents of a file rather than passing as a string.
-
-### Update the `Dockerfile` for optimised caching
-
-```Dockerfile
-FROM public.ecr.aws/lambda/nodejs:24
-
-ENV AWS_LAMBDA_FUNCTION_MEMORY_SIZE=128
-ENV AWS_LAMBDA_FUNCTION_TIMEOUT=3
-ENV AWS_LAMBDA_LOG_FORMAT=JSON
-
-HEALTHCHECK --interval=1s --timeout=1s --retries=30 \
-    CMD [ "curl", "-I", "http://localhost:8080" ]
-
-COPY ./nodejs/package*.json ${LAMBDA_TASK_ROOT}
-
-RUN npm ci
-
-COPY ./nodejs ${LAMBDA_TASK_ROOT}
-
-RUN npm run build
-
-CMD [ "build/index.handler" ]
-```
-
-### Update the `Dockerfile` for multi-stage builds
-
-```Dockerfile
-FROM public.ecr.aws/lambda/nodejs:24 AS base
-
-ENV AWS_LAMBDA_FUNCTION_MEMORY_SIZE=128
-ENV AWS_LAMBDA_FUNCTION_TIMEOUT=3
-ENV AWS_LAMBDA_LOG_FORMAT=JSON
-
-HEALTHCHECK --interval=1s --timeout=1s --retries=30 \
-    CMD [ "curl", "-I", "http://localhost:8080" ]
-
-FROM base AS build
-
-COPY ./nodejs/package*.json ${LAMBDA_TASK_ROOT}
-
-RUN npm ci
-
-COPY ./nodejs ${LAMBDA_TASK_ROOT}
-
-RUN npm run build
-
-FROM base
-
-COPY --from=build ${LAMBDA_TASK_ROOT}/package*.json ${LAMBDA_TASK_ROOT}
-COPY --from=build ${LAMBDA_TASK_ROOT}/build ${LAMBDA_TASK_ROOT}/build
-
-RUN npm ci --only=production
-
-CMD [ "build/index.handler" ]
-```
-
-### Create a `python` directory
-
-### Create a `./python/Dockerfile`
-
-### Create the `./python/requirements.txt`
-
-### Create the handler file at `./python/app.py`
-
-### Update `docker-compose.yaml`
-
-### Run the Lambda
-
-- SAM
-
-- cleanup
-
 ---
-
-## 🎉 Congratulations
-
-You've just learnt to build and develop AWS Lambda functions locally with Docker.
-
-### Recap of what you built