Lab 00: APIs, JSON, and Python Scripting

Objective

Create and read JSON files, call a public API that returns JSON, and write and run a Python script that uses variables, a function, and a loop.

Prerequisites

• A terminal application:
  • macOS: Terminal.app (pre-installed in Applications > Utilities)
  • Windows: Git Bash (bundled with Git for Windows)
  • Linux: Terminal (pre-installed)
• Module 02 (The Command Line) for basic terminal skills
• Python 3 installed:
  • macOS: brew install python3 or download from python.org
  • Windows: Download from python.org
  • Linux: sudo apt install python3 or sudo dnf install python3

Duration

15 to 18 minutes

Instructions

Step 1: Work with JSON (~7-8 min)

In this step you create a JSON file, display its contents, and call a public API that returns JSON.

Create a working directory:

mkdir -p it-fundamentals-lab
cd it-fundamentals-lab

Create a JSON file:

cat > data.json << 'EOF'
{
  "name": "IT Fundamentals Lab",
  "version": 1,
  "topics": ["command line", "git", "networking", "json", "python"],
  "completed": false
}
EOF

This command creates a file called data.json and writes the JSON content into it. It produces no output.

✅Tip: The << 'EOF' syntax is called a "here document." It lets you write multiple lines of text into a file. Everything between << 'EOF' and the closing EOF is written to the file.

Display the JSON file:

cat data.json

Expected output:

{
  "name": "IT Fundamentals Lab",
  "version": 1,
  "topics": ["command line", "git", "networking", "json", "python"],
  "completed": false
}

This is valid JSON. Notice the structure: keys are strings in double quotes, values can be strings, numbers, arrays (lists in square brackets), or booleans (true/false).

Call a public API that returns JSON:

curl -s https://httpbin.org/json

Expected output:

{
  "slideshow": {
    "author": "Yours Truly",
    "date": "date of publication",
    "slides": [
      {
        "title": "Wake up to WonderWidgets!",
        "type": "all"
      },
      {
        "items": [
          "Why <em>WonderWidgets</em> are great",
          "Who <em>buys</em> WonderWidgets"
        ],
        "title": "Overview",
        "type": "all"
      }
    ],
    "title": "Sample Slide Show"
  }
}

This API returns a sample JSON response with nested objects and arrays. In the AWS Bootcamp, you will work with JSON constantly: IAM policies, CloudFormation templates, and API responses all use this format.

Step 2: Write and Run a Python Script (~8-10 min)

In this step you create a Python script that uses variables, a function, and a loop, then run it from the command line.

Create the Python script:

cat > hello.py << 'EOF'
# IT Fundamentals Lab - Python Script

# Variables
student_name = "Bootcamp Student"
topics = ["Cloud", "IAM", "VPC", "EC2", "S3"]

# Function
def greet(name):
    return f"Welcome to the AWS Bootcamp, {name}"

# Print greeting
message = greet(student_name)
print(message)

# Loop
print("\nBootcamp topics you will learn:")
for i, topic in enumerate(topics, 1):
    print(f"  {i}. {topic}")

print(f"\nTotal topics: {len(topics)}")
EOF

This command creates a file called hello.py with a complete Python script. It produces no output.

View the script to confirm it was created:

cat hello.py

Expected output:

# IT Fundamentals Lab - Python Script

# Variables
student_name = "Bootcamp Student"
topics = ["Cloud", "IAM", "VPC", "EC2", "S3"]

# Function
def greet(name):
    return f"Welcome to the AWS Bootcamp, {name}"

# Print greeting
message = greet(student_name)
print(message)

# Loop
print("\nBootcamp topics you will learn:")
for i, topic in enumerate(topics, 1):
    print(f"  {i}. {topic}")

print(f"\nTotal topics: {len(topics)}")

Run the script:

macOS/Linux:

python3 hello.py

Windows (Git Bash or PowerShell):

python hello.py

✅Tip: On Windows, the Python installer registers the command as python (not python3). If python does not work, try python3. If neither works, verify that Python is installed by running python --version or python3 --version.

Expected output:

Welcome to the AWS Bootcamp, Bootcamp Student

Bootcamp topics you will learn:
  1. Cloud
  2. IAM
  3. VPC
  4. EC2
  5. S3

Total topics: 5

This script demonstrates three core programming concepts:

• Variables: student_name stores a string, topics stores a list.
• Function: greet() takes a name as input and returns a greeting string.
• Loop: The for loop iterates over the topics list and prints each item with a number.

These are the same concepts you will use when writing AWS Lambda functions in Module 09: Serverless (Lambda).

Validation

Confirm the following before moving on:

• The data.json file contains valid JSON with 5 topics
• Running curl -s https://httpbin.org/json returns a JSON response with nested objects
• Running python3 hello.py (or python hello.py on Windows) prints the greeting and 5 topics

Cleanup

Remove the lab directory when you are finished:

macOS/Linux:

cd ~
rm -r it-fundamentals-lab

Windows (Git Bash):

cd ~
rm -r it-fundamentals-lab

Windows (PowerShell):

cd $HOME
Remove-Item -Recurse -Force it-fundamentals-lab

No cloud resources were created during this lab. No further cleanup is needed.

Challenge (Optional)

1. Write a Python script that reads data.json and prints each topic. Hint: use import json, then json.load() to read the file, and a for loop to print each item in the topics list.

2. Use curl to call https://httpbin.org/headers and save the response to a file called headers.json:

   curl -s https://httpbin.org/headers > headers.json
   cat headers.json
   

3. Modify hello.py to add a dictionary variable and print its key-value pairs using a loop.

AWS Bootcamp: From Novice to Architect Author: Samuel Ogunti License: CC BY-NC 4.0