# Cloudflare DNS Updater

A Bash script that automatically updates Cloudflare DNS A records with your current public IP address. This script demonstrates various advanced Bash programming features while providing a practical tool for dynamic DNS management.

## Features

- **Automatic IP Detection**: Retrieves current public IP using external services
- **Multi-Domain Support**: Manages DNS records for multiple domains simultaneously
- **Smart Updates**: Only updates records when IP changes to avoid unnecessary API calls
- **Orphaned Record Cleanup**: Automatically removes unmanaged DNS records
- **Protected Records**: Prevents deletion of critical DNS records
- **Dry Run Mode**: Test changes without actually modifying DNS records
- **Comprehensive Logging**: Detailed output showing all operations performed

## Bash Features Demonstrated

This script showcases the following Bash programming features:

### 1. **Shebang and Script Structure**
```bash
#!/bin/bash
```
Proper script initialization with bash interpreter specification.

### 2. **Variable Declarations and Constants**
```bash
TOKEN=""
AUTO_DELETE_ORPHANS=true
DRY_RUN=false
```
Use of string constants and boolean flags for configuration.

### 3. **Associative Arrays**
```bash
declare -A d0 d1  # Declare associative arrays for domain configuration
d0=(
    ["domain"]=""
    ["zone_id"]=""
    ["subdomains"]="@,"
    ["protected_records"]=""
)
```
Key-value data structures for complex domain configurations.

### 4. **Indexed Arrays**
```bash
declare -a domains  # Declare indexed array to hold domain references
domains=( d0 d1 )
```
Ordered collections for managing multiple domains.

### 5. **Array References (Namerefs)**
```bash
declare -n domain="$item"  # Create reference to associative array
echo "${domain[domain]}"  # Access array elements through reference
```
Dynamic array referencing for flexible data access.

### 6. **Functions**
```bash
get_current_ip() {
    curl -s https://ifconfig.me/ip
}

create_dns_record() {
    local zone_id="$1"
    local data="$2"
    # Function implementation
}
```
Modular code organization with local variables and parameters.

### 7. **Advanced Conditional Statements**
```bash
if [[ "$DRY_RUN" == true ]]; then
    echo "⚠️  DRY RUN MODE ENABLED"
fi

if [[ -n "${existing_a_records[$full_name]}" ]]; then
    # Record exists logic
fi
```
String comparison, variable existence checks, and complex conditions.

### 8. **Loop Constructs**
```bash
for item in "${domains[@]}"; do
    # Process each domain
done

for subdomain in "${managed_subdomains[@]}"; do
    # Process each subdomain
done
```
Iteration over arrays with proper quoting.

### 9. **String Manipulation and Parsing**
```bash
IFS=',' read -ra protected_records <<< "${domain[protected_records]}"
IFS=',' read -ra managed_subdomains <<< "${domain[subdomains]}"
```
Field splitting and array population from comma-separated strings.

### 10. **Command and Process Substitution**
```bash
current_ip=$(get_current_ip)  # Command substitution

done < <(echo "$response" | jq -c '.result[] | select(.type == "A")')  # Process substitution
```
Capturing command output and feeding output to loops.

### 11. **JSON Processing with jq**
```bash
if echo "$response" | jq -e '.success == false' > /dev/null 2>&1; then
    echo "Error: Failed to get DNS records"
fi

create_data=$(jq -n \
    --arg name "$full_name" \
    --arg ip "$current_ip" \
    '{
        "type": "A",
        "name": $name,
        "content": $ip,
        "ttl": 1,
        "proxied": true
    }')
```
Parsing JSON responses and constructing JSON payloads.

### 12. **Error Handling and Exit Codes**
```bash
if [ -z "$current_ip" ]; then
    echo "Error: Could not retrieve current IP"
    exit 1
fi
```
Input validation and controlled script termination.

### 13. **Arithmetic Operations**
```bash
((records_created++))
((records_updated++))
((records_skipped++))
((records_deleted++))
```
Counter variables for operation statistics.

### 14. **API Integration with curl**
```bash
curl -s "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records" \
    -X POST \
    -H 'Content-Type: application/json' \
    -H "Authorization: Bearer $TOKEN" \
    -d "$data"
```
REST API calls with proper headers and data payloads.

### 15. **Dynamic Variable Management**
```bash
unset existing_a_records  # Clean up associative arrays
unset domain             # Clean up nameref
```
Memory management and variable cleanup.

## Usage

1. **Configure Domains**: Edit the domain arrays at the top of the script
2. **Set API Token**: Update the `TOKEN` variable with your Cloudflare API token
3. **Dry Run First**: Test with `DRY_RUN=true` to see what would change
4. **Run Updates**: Set `DRY_RUN=false` to apply actual changes

```bash
# Dry run (safe testing)
./update_domain.sh

# Apply changes
# Edit script: DRY_RUN=false
./update_domain.sh
```

## Configuration

### Domain Configuration Structure
Each domain is configured as an associative array with:
- `domain`: The root domain name
- `zone_id`: Cloudflare zone identifier
- `subdomains`: Comma-separated list of subdomains to manage
- `protected_records`: Records that should never be deleted

### Script Parameters
- `TOKEN`: Cloudflare API bearer token
- `AUTO_DELETE_ORPHANS`: Whether to remove unmanaged records
- `DRY_RUN`: Test mode without making actual changes

## Requirements

- Bash 4.0+
- curl
- jq
- Valid Cloudflare API token with DNS edit permissions

## Security Notes

- Store API tokens securely (consider environment variables)
- Use dry run mode when testing
- Review protected records configuration carefully
- Monitor script output for any API errors

## Output Example

```
⚠️  DRY RUN MODE ENABLED - No actual changes will be made
=========================================
Current Public IP: 203.0.113.1
=========================================
Processing domain: my-dev.pro
Zone ID: 5c9a19af6aeababb78b294844290a7d2
Managed subdomains: @ git
----------------------------------------
Existing A records:
  - my-dev.pro → 203.0.113.1 (ID: abc123)
  - git.my-dev.pro → 203.0.113.1 (ID: def456)
----------------------------------------
Checking: my-dev.pro
  ✓ SKIPPED: IP unchanged (203.0.113.1 = 203.0.113.1)
Checking: git.my-dev.pro
  ✓ SKIPPED: IP unchanged (203.0.113.1 = 203.0.113.1)
=========================================
SUMMARY for my-dev.pro:
  ✓ Created: 0
  ✓ Updated: 0
  ✓ Skipped (IP unchanged): 2
  ✓ Deleted: 0
=========================================
⚠️  DRY RUN COMPLETED - No actual changes were made
Set DRY_RUN=false to apply changes
```