cloudfront-gettingstarted.sh

#!/bin/bash

# CloudFront Getting Started Tutorial Script
# This script creates an S3 bucket, uploads sample content, creates a CloudFront distribution with OAC,
# and demonstrates how to access content through CloudFront.

set -euo pipefail

# Set up logging
LOG_FILE="cloudfront-tutorial.log"
exec > >(tee -a "$LOG_FILE") 2>&1

echo "Starting CloudFront Getting Started Tutorial at $(date)"

# Function to handle errors
handle_error() {
    echo "ERROR: $1" >&2
    echo "Resources created before error:"
    if [ -n "${BUCKET_NAME:-}" ]; then
        echo "- S3 Bucket: $BUCKET_NAME"
    fi
    if [ -n "${OAC_ID:-}" ]; then
        echo "- CloudFront Origin Access Control: $OAC_ID"
    fi
    if [ -n "${DISTRIBUTION_ID:-}" ]; then
        echo "- CloudFront Distribution: $DISTRIBUTION_ID"
    fi
    
    echo "Attempting to clean up resources..."
    cleanup
    exit 1
}

# Function to clean up resources
cleanup() {
    echo "Cleaning up resources..."
    
    if [ -n "${DISTRIBUTION_ID:-}" ]; then
        echo "Disabling CloudFront distribution $DISTRIBUTION_ID..."
        
        # Get the current configuration and ETag in one call
        DIST_CONFIG=$(aws cloudfront get-distribution-config --id "$DISTRIBUTION_ID" 2>/dev/null) || {
            echo "Failed to get distribution config. Continuing with cleanup..."
            DIST_CONFIG=""
        }
        
        if [ -n "$DIST_CONFIG" ]; then
            ETAG=$(echo "$DIST_CONFIG" | jq -r '.ETag')
            
            # Modify and update distribution in one pipeline
            if echo "$DIST_CONFIG" | jq '.DistributionConfig.Enabled = false' | \
                aws cloudfront update-distribution \
                    --id "$DISTRIBUTION_ID" \
                    --distribution-config "$(cat)" \
                    --if-match "$ETAG" 2>/dev/null; then
                
                echo "Waiting for distribution to be disabled (this may take several minutes)..."
                aws cloudfront wait distribution-deployed --id "$DISTRIBUTION_ID" 2>/dev/null || {
                    echo "Distribution deployment wait timed out. Proceeding with deletion..."
                }
                
                # Get fresh ETag for deletion
                DIST_CONFIG=$(aws cloudfront get-distribution-config --id "$DISTRIBUTION_ID" 2>/dev/null) || {
                    echo "Failed to get updated config. Skipping distribution deletion..."
                    DIST_CONFIG=""
                }
                
                if [ -n "$DIST_CONFIG" ]; then
                    ETAG=$(echo "$DIST_CONFIG" | jq -r '.ETag')
                    aws cloudfront delete-distribution --id "$DISTRIBUTION_ID" --if-match "$ETAG" 2>/dev/null && \
                        echo "CloudFront distribution deleted." || \
                        echo "Failed to delete distribution. You may need to delete it manually."
                fi
            else
                echo "Failed to disable distribution. Continuing with cleanup..."
            fi
        fi
    fi
    
    if [ -n "${OAC_ID:-}" ]; then
        echo "Deleting Origin Access Control $OAC_ID..."
        OAC_DATA=$(aws cloudfront get-origin-access-control --id "$OAC_ID" 2>/dev/null) || {
            echo "Failed to get Origin Access Control. You may need to delete it manually."
            OAC_DATA=""
        }
        
        if [ -n "$OAC_DATA" ]; then
            OAC_ETAG=$(echo "$OAC_DATA" | jq -r '.ETag')
            aws cloudfront delete-origin-access-control --id "$OAC_ID" --if-match "$OAC_ETAG" 2>/dev/null && \
                echo "Origin Access Control deleted." || \
                echo "Failed to delete Origin Access Control. You may need to delete it manually."
        fi
    fi
    
    if [ -n "${BUCKET_NAME:-}" ] && [ "$BUCKET_IS_SHARED" != "true" ]; then
        echo "Deleting S3 bucket $BUCKET_NAME and its contents..."
        aws s3 rm "s3://$BUCKET_NAME" --recursive 2>/dev/null || {
            echo "Failed to remove bucket contents. Continuing with bucket deletion..."
        }
        
        aws s3 rb "s3://$BUCKET_NAME" 2>/dev/null && \
            echo "S3 bucket deleted." || \
            echo "Failed to delete bucket. You may need to delete it manually."
    fi
    
    # Clean up temporary files
    rm -f temp_disabled_config.json distribution-config.json bucket-policy.json 2>/dev/null || true
    rm -rf temp_content 2>/dev/null || true
}

# Trap errors and cleanup
trap 'handle_error "Script interrupted"' INT TERM

# Validate AWS CLI is available
if ! command -v aws &> /dev/null; then
    handle_error "AWS CLI is not installed or not in PATH"
fi

# Validate jq is available
if ! command -v jq &> /dev/null; then
    handle_error "jq is not installed or not in PATH"
fi

# Validate AWS credentials are configured
if ! aws sts get-caller-identity &> /dev/null; then
    handle_error "AWS credentials are not configured or invalid"
fi

# Initialize variables
BUCKET_NAME=""
OAC_ID=""
DISTRIBUTION_ID=""
BUCKET_IS_SHARED=false

# Generate a random identifier for the bucket name using secure random
RANDOM_ID=$(openssl rand -hex 6)
if [ -z "$RANDOM_ID" ]; then
    handle_error "Failed to generate random identifier"
fi

# Check for shared prereq bucket and get account ID in parallel calls
PREREQ_BUCKET=$(aws cloudformation describe-stacks --stack-name tutorial-prereqs-bucket \
    --query 'Stacks[0].Outputs[?OutputKey==`BucketName`].OutputValue' --output text 2>/dev/null) || PREREQ_BUCKET=""

if [ -n "$PREREQ_BUCKET" ] && [ "$PREREQ_BUCKET" != "None" ]; then
    BUCKET_NAME="$PREREQ_BUCKET"
    BUCKET_IS_SHARED=true
    echo "Using shared bucket: $BUCKET_NAME"
else
    BUCKET_IS_SHARED=false
    BUCKET_NAME="cloudfront-${RANDOM_ID}"
fi
echo "Using bucket name: $BUCKET_NAME"

# Get AWS account ID early
ACCOUNT_ID=$(aws sts get-caller-identity --query 'Account' --output text)
if [ $? -ne 0 ]; then
    handle_error "Failed to get AWS account ID"
fi

# Validate account ID format
if ! [[ "$ACCOUNT_ID" =~ ^[0-9]{12}$ ]]; then
    handle_error "Invalid AWS account ID format: $ACCOUNT_ID"
fi

# Create a temporary directory for content with restrictive permissions
TEMP_DIR="temp_content"
mkdir -p "$TEMP_DIR/css"
chmod 700 "$TEMP_DIR"
if [ $? -ne 0 ]; then
    handle_error "Failed to create temporary directory"
fi

# Step 1: Create an S3 bucket (only if not shared)
if [ "$BUCKET_IS_SHARED" != "true" ]; then
    echo "Creating S3 bucket: $BUCKET_NAME"
    aws s3 mb "s3://$BUCKET_NAME" --region us-east-1
    if [ $? -ne 0 ]; then
        handle_error "Failed to create S3 bucket"
    fi
    
    aws s3api put-bucket-tagging --bucket "$BUCKET_NAME" --tagging 'TagSet=[{Key=project,Value=doc-smith},{Key=tutorial,Value=cloudfront-gettingstarted}]'
    
    # Batch bucket configuration calls for efficiency
    aws s3api put-bucket-versioning --bucket "$BUCKET_NAME" --versioning-configuration Status=Enabled &
    aws s3api put-public-access-block \
        --bucket "$BUCKET_NAME" \
        --public-access-block-configuration "BlockPublicAcls=true,IgnorePublicAcls=true,BlockPublicPolicy=true,RestrictPublicBuckets=true" &
    aws s3api put-bucket-encryption \
        --bucket "$BUCKET_NAME" \
        --server-side-encryption-configuration '{
            "Rules": [
                {
                    "ApplyServerSideEncryptionByDefault": {
                        "SSEAlgorithm": "AES256"
                    }
                }
            ]
        }' &
    wait
fi

# Step 2: Create sample content
echo "Creating sample content..."
cat > "$TEMP_DIR/index.html" << 'EOF'
<!DOCTYPE html>
<html>
<head>
    <title>Hello World</title>
    <link rel="stylesheet" type="text/css" href="css/styles.css">
</head>
<body>
    <h1>Hello world!</h1>
</body>
</html>
EOF

cat > "$TEMP_DIR/css/styles.css" << 'EOF'
body {
    font-family: Arial, sans-serif;
    margin: 40px;
    background-color: #f5f5f5;
}
h1 {
    color: #333;
    text-align: center;
}
EOF

# Set restrictive permissions on content files
chmod 600 "$TEMP_DIR/index.html" "$TEMP_DIR/css/styles.css"

# Step 3: Upload content to the S3 bucket with encryption and metadata
echo "Uploading content to S3 bucket..."
aws s3 cp "$TEMP_DIR/" "s3://$BUCKET_NAME/" --recursive \
    --sse AES256 \
    --metadata "Source=CloudFrontTutorial"
if [ $? -ne 0 ]; then
    handle_error "Failed to upload content to S3 bucket"
fi

# Step 4: Create Origin Access Control
echo "Creating Origin Access Control..."
OAC_RESPONSE=$(aws cloudfront create-origin-access-control \
    --origin-access-control-config Name="oac-for-$BUCKET_NAME",SigningProtocol=sigv4,SigningBehavior=always,OriginAccessControlOriginType=s3)

if [ $? -ne 0 ]; then
    handle_error "Failed to create Origin Access Control"
fi

OAC_ID=$(echo "$OAC_RESPONSE" | jq -r '.OriginAccessControl.Id')
if [ -z "$OAC_ID" ] || [ "$OAC_ID" = "null" ]; then
    handle_error "Failed to extract OAC ID from response"
fi

# Validate OAC ID format (alphanumeric and hyphens)
if ! [[ "$OAC_ID" =~ ^[A-Z0-9]+$ ]]; then
    handle_error "Invalid OAC ID format: $OAC_ID"
fi

echo "Created Origin Access Control with ID: $OAC_ID"

# Step 5: Create CloudFront distribution
echo "Creating CloudFront distribution..."

# Validate bucket name format
if ! [[ "$BUCKET_NAME" =~ ^[a-z0-9][a-z0-9.-]*[a-z0-9]$ ]]; then
    handle_error "Invalid S3 bucket name format: $BUCKET_NAME"
fi

# Create distribution configuration with improved security settings
cat > distribution-config.json << EOF
{
    "CallerReference": "cli-tutorial-$(date +%s)",
    "Origins": {
        "Quantity": 1,
        "Items": [
            {
                "Id": "S3-$BUCKET_NAME",
                "DomainName": "$BUCKET_NAME.s3.amazonaws.com",
                "S3OriginConfig": {
                    "OriginAccessIdentity": ""
                },
                "OriginAccessControlId": "$OAC_ID"
            }
        ]
    },
    "DefaultCacheBehavior": {
        "TargetOriginId": "S3-$BUCKET_NAME",
        "ViewerProtocolPolicy": "redirect-to-https",
        "AllowedMethods": {
            "Quantity": 2,
            "Items": ["GET", "HEAD"],
            "CachedMethods": {
                "Quantity": 2,
                "Items": ["GET", "HEAD"]
            }
        },
        "DefaultTTL": 86400,
        "MinTTL": 0,
        "MaxTTL": 31536000,
        "Compress": true,
        "ForwardedValues": {
            "QueryString": false,
            "Cookies": {
                "Forward": "none"
            }
        }
    },
    "Comment": "CloudFront distribution for tutorial",
    "Enabled": true,
    "WebACLId": "",
    "HttpVersion": "http2and3"
}
EOF

# Set restrictive permissions on config file before passing credentials
chmod 600 distribution-config.json

DIST_RESPONSE=$(aws cloudfront create-distribution --distribution-config file://distribution-config.json)
if [ $? -ne 0 ]; then
    handle_error "Failed to create CloudFront distribution"
fi

DISTRIBUTION_ID=$(echo "$DIST_RESPONSE" | jq -r '.Distribution.Id')
DOMAIN_NAME=$(echo "$DIST_RESPONSE" | jq -r '.Distribution.DomainName')

if [ -z "$DISTRIBUTION_ID" ] || [ "$DISTRIBUTION_ID" = "null" ] || [ -z "$DOMAIN_NAME" ] || [ "$DOMAIN_NAME" = "null" ]; then
    handle_error "Failed to extract distribution ID or domain name from response"
fi

# Validate distribution ID format
if ! [[ "$DISTRIBUTION_ID" =~ ^[A-Z0-9]+$ ]]; then
    handle_error "Invalid distribution ID format: $DISTRIBUTION_ID"
fi

echo "Created CloudFront distribution with ID: $DISTRIBUTION_ID"
echo "CloudFront domain name: $DOMAIN_NAME"

# Tag the CloudFront distribution
aws cloudfront tag-resource --resource "arn:aws:cloudfront::$ACCOUNT_ID:distribution/$DISTRIBUTION_ID" --tags 'Items=[{Key=project,Value=doc-smith},{Key=tutorial,Value=cloudfront-gettingstarted}]'

# Step 6: Update S3 bucket policy
echo "Updating S3 bucket policy..."

cat > bucket-policy.json << EOF
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowCloudFrontServicePrincipal",
            "Effect": "Allow",
            "Principal": {
                "Service": "cloudfront.amazonaws.com"
            },
            "Action": "s3:GetObject",
            "Resource": "arn:aws:s3:::$BUCKET_NAME/*",
            "Condition": {
                "StringEquals": {
                    "AWS:SourceArn": "arn:aws:cloudfront::$ACCOUNT_ID:distribution/$DISTRIBUTION_ID"
                }
            }
        }
    ]
}
EOF

# Set restrictive permissions on policy file
chmod 600 bucket-policy.json

aws s3api put-bucket-policy --bucket "$BUCKET_NAME" --policy file://bucket-policy.json
if [ $? -ne 0 ]; then
    handle_error "Failed to update S3 bucket policy"
fi

# Step 7: Wait for distribution to deploy
echo "Waiting for CloudFront distribution to deploy (this may take 5-10 minutes)..."
aws cloudfront wait distribution-deployed --id "$DISTRIBUTION_ID" 2>/dev/null || {
    echo "Warning: Distribution deployment wait timed out. The distribution may still be deploying."
}

echo "CloudFront distribution is now deployed."

# Step 8: Display access information
echo ""
echo "===== CloudFront Distribution Setup Complete ====="
echo "You can access your content at: https://$DOMAIN_NAME/index.html"
echo ""
echo "Resources created:"
echo "- S3 Bucket: $BUCKET_NAME"
echo "- CloudFront Origin Access Control: $OAC_ID"
echo "- CloudFront Distribution: $DISTRIBUTION_ID"
echo ""
echo "To clean up resources, run: cleanup"
echo ""

echo "Tutorial completed at $(date)"