Redis Cache Invalidator

Hook Content

The main content for this hook.

post-tool-use.json

json

{
  "hookConfig": {
    "hooks": {
      "postToolUse": {
        "script": "./.claude/hooks/redis-cache-invalidator.sh",
        "matchers": [
          "write",
          "edit"
        ]
      }
    }
  },
  "scriptContent": "#!/bin/bash\n\n# Read the tool input from stdin\nINPUT=$(cat)\nTOOL_NAME=$(echo \"$INPUT\" | jq -r '.tool_name')\nFILE_PATH=$(echo \"$INPUT\" | jq -r '.tool_input.file_path // .tool_input.path // \"\"')\n\nif [ -z \"$FILE_PATH\" ]; then\n  exit 0\nfi\n\necho \"🔄 Redis Cache Invalidator - Analyzing file changes...\"\necho \"📄 File: $FILE_PATH\"\n\n# Check if this is a model or data file that should trigger cache invalidation\nif [[ \"$FILE_PATH\" == *models/*.js ]] || [[ \"$FILE_PATH\" == *models/*.py ]] || [[ \"$FILE_PATH\" == *models/*.ts ]] || [[ \"$FILE_PATH\" == *schemas/*.* ]] || [[ \"$FILE_PATH\" == *entities/*.* ]]; then\n    \n    MODEL_NAME=$(basename \"${FILE_PATH%.*}\")\n    echo \"📊 Model detected: $MODEL_NAME\"\n    \n    # Check if Redis CLI is available\n    if ! command -v redis-cli >/dev/null 2>&1; then\n        echo \"⚠️ redis-cli not found - please install Redis CLI tools\"\n        echo \"💡 Install with: apt-get install redis-tools (Ubuntu) or brew install redis (macOS)\"\n        exit 0\n    fi\n    \n    # Test Redis connection\n    if ! redis-cli ping >/dev/null 2>&1; then\n        echo \"⚠️ Redis server not accessible - skipping cache invalidation\"\n        echo \"💡 Ensure Redis server is running and accessible\"\n        exit 0\n    fi\n    \n    echo \"🔍 Scanning for cache keys related to: $MODEL_NAME\"\n    \n    # Find cache keys related to this model\n    CACHE_KEYS=$(redis-cli --scan --pattern \"*${MODEL_NAME}*\" 2>/dev/null)\n    \n    if [ -n \"$CACHE_KEYS\" ]; then\n        KEY_COUNT=$(echo \"$CACHE_KEYS\" | wc -l)\n        echo \"🗑️ Found $KEY_COUNT cache keys to invalidate:\"\n        \n        # Show first few keys for confirmation\n        echo \"$CACHE_KEYS\" | head -5 | while read -r key; do\n            echo \"  • $key\"\n        done\n        \n        if [ \"$KEY_COUNT\" -gt 5 ]; then\n            echo \"  ... and $((KEY_COUNT - 5)) more keys\"\n        fi\n        \n        # Delete the keys\n        echo \"$CACHE_KEYS\" | xargs -r redis-cli DEL >/dev/null 2>&1\n        echo \"✅ Invalidated $KEY_COUNT cache keys for model: $MODEL_NAME\"\n    else\n        echo \"ℹ️ No cache keys found for model: $MODEL_NAME\"\n    fi\n    \n    # Additional patterns to check\n    echo \"🔍 Checking additional cache patterns...\"\n    \n    # Check for API route caches\n    API_KEYS=$(redis-cli --scan --pattern \"api:*${MODEL_NAME}*\" 2>/dev/null)\n    if [ -n \"$API_KEYS\" ]; then\n        API_COUNT=$(echo \"$API_KEYS\" | wc -l)\n        echo \"$API_KEYS\" | xargs -r redis-cli DEL >/dev/null 2>&1\n        echo \"✅ Invalidated $API_COUNT API cache keys\"\n    fi\n    \n    # Check for query result caches\n    QUERY_KEYS=$(redis-cli --scan --pattern \"query:*${MODEL_NAME}*\" 2>/dev/null)\n    if [ -n \"$QUERY_KEYS\" ]; then\n        QUERY_COUNT=$(echo \"$QUERY_KEYS\" | wc -l)\n        echo \"$QUERY_KEYS\" | xargs -r redis-cli DEL >/dev/null 2>&1\n        echo \"✅ Invalidated $QUERY_COUNT query cache keys\"\n    fi\n    \n    # Check current Redis stats\n    echo \"\"\n    echo \"📊 Redis Cache Statistics:\"\n    TOTAL_KEYS=$(redis-cli DBSIZE 2>/dev/null || echo \"unknown\")\n    MEMORY_USAGE=$(redis-cli INFO memory 2>/dev/null | grep used_memory_human | cut -d: -f2 | tr -d '\\r' || echo \"unknown\")\n    echo \"  • Total keys: $TOTAL_KEYS\"\n    echo \"  • Memory usage: $MEMORY_USAGE\"\n    \n    echo \"\"\n    echo \"💡 Cache Invalidation Tips:\"\n    echo \"  • Use consistent cache key naming patterns\"\n    echo \"  • Consider cache TTL for automatic expiration\"\n    echo \"  • Monitor cache hit/miss ratios\"\n    echo \"  • Use Redis keyspace notifications for advanced invalidation\"\n    \n    echo \"\"\n    echo \"🎯 Cache invalidation complete!\"\n    \nelif [[ \"$FILE_PATH\" == *config/*.* ]] || [[ \"$FILE_PATH\" == *.env ]]; then\n    echo \"⚙️ Configuration file detected - consider full cache flush if needed\"\n    echo \"💡 Run 'redis-cli FLUSHDB' manually if configuration affects cached data\"\n    \nelse\n    echo \"ℹ️ File does not require cache invalidation: $FILE_PATH\"\nfi\n\nexit 0"
}

Features

Key capabilities and functionality

Intelligent cache key invalidation
Model-based cache clearing
Pattern matching for cache keys
Safe asynchronous cache flushing
Multi-language model support
Cache consistency maintenance

Installation

Setup instructions and requirements

Claude Code Setup

Create hooks directory: mkdir -p .claude/hooks
Create hook script: .claude/hooks/redis-cache-invalidator.sh
Add hook configuration to your Claude Code config
Make script executable: chmod +x .claude/hooks/redis-cache-invalidator.sh
Restart Claude Code to activate the hook

Configuration Paths

project

.claude/hooks/

user

~/.claude/hooks/

Requirements

Claude Code CLI
Bash shell
Hook-specific dependencies (e.g., jq, prettier)

Hook Configuration

Hook setup and script content

post-tool-use-config.json

json

{
  "hooks": {
    "postToolUse": {
      "script": "./.claude/hooks/redis-cache-invalidator.sh",
      "matchers": [
        "write",
        "edit"
      ]
    }
  }
}

post-tool-use-script.sh

bash

#!/bin/bash

# Read the tool input from stdin
INPUT=$(cat)
TOOL_NAME=$(echo "$INPUT" | jq -r '.tool_name')
FILE_PATH=$(echo "$INPUT" | jq -r '.tool_input.file_path // .tool_input.path // ""')

if [ -z "$FILE_PATH" ]; then
  exit 0
fi

echo "🔄 Redis Cache Invalidator - Analyzing file changes..."
echo "📄 File: $FILE_PATH"

# Check if this is a model or data file that should trigger cache invalidation
if [[ "$FILE_PATH" == *models/*.js ]] || [[ "$FILE_PATH" == *models/*.py ]] || [[ "$FILE_PATH" == *models/*.ts ]] || [[ "$FILE_PATH" == *schemas/*.* ]] || [[ "$FILE_PATH" == *entities/*.* ]]; then
    
    MODEL_NAME=$(basename "${FILE_PATH%.*}")
    echo "📊 Model detected: $MODEL_NAME"
    
    # Check if Redis CLI is available
    if ! command -v redis-cli >/dev/null 2>&1; then
        echo "⚠️ redis-cli not found - please install Redis CLI tools"
        echo "💡 Install with: apt-get install redis-tools (Ubuntu) or brew install redis (macOS)"
        exit 0
    fi
    
    # Test Redis connection
    if ! redis-cli ping >/dev/null 2>&1; then
        echo "⚠️ Redis server not accessible - skipping cache invalidation"
        echo "💡 Ensure Redis server is running and accessible"
        exit 0
    fi
    
    echo "🔍 Scanning for cache keys related to: $MODEL_NAME"
    
    # Find cache keys related to this model
    CACHE_KEYS=$(redis-cli --scan --pattern "*${MODEL_NAME}*" 2>/dev/null)
    
    if [ -n "$CACHE_KEYS" ]; then
        KEY_COUNT=$(echo "$CACHE_KEYS" | wc -l)
        echo "🗑️ Found $KEY_COUNT cache keys to invalidate:"
        
        # Show first few keys for confirmation
        echo "$CACHE_KEYS" | head -5 | while read -r key; do
            echo "  • $key"
        done
        
        if [ "$KEY_COUNT" -gt 5 ]; then
            echo "  ... and $((KEY_COUNT - 5)) more keys"
        fi
        
        # Delete the keys
        echo "$CACHE_KEYS" | xargs -r redis-cli DEL >/dev/null 2>&1
        echo "✅ Invalidated $KEY_COUNT cache keys for model: $MODEL_NAME"
    else
        echo "ℹ️ No cache keys found for model: $MODEL_NAME"
    fi
    
    # Additional patterns to check
    echo "🔍 Checking additional cache patterns..."
    
    # Check for API route caches
    API_KEYS=$(redis-cli --scan --pattern "api:*${MODEL_NAME}*" 2>/dev/null)
    if [ -n "$API_KEYS" ]; then
        API_COUNT=$(echo "$API_KEYS" | wc -l)
        echo "$API_KEYS" | xargs -r redis-cli DEL >/dev/null 2>&1
        echo "✅ Invalidated $API_COUNT API cache keys"
    fi
    
    # Check for query result caches
    QUERY_KEYS=$(redis-cli --scan --pattern "query:*${MODEL_NAME}*" 2>/dev/null)
    if [ -n "$QUERY_KEYS" ]; then
        QUERY_COUNT=$(echo "$QUERY_KEYS" | wc -l)
        echo "$QUERY_KEYS" | xargs -r redis-cli DEL >/dev/null 2>&1
        echo "✅ Invalidated $QUERY_COUNT query cache keys"
    fi
    
    # Check current Redis stats
    echo ""
    echo "📊 Redis Cache Statistics:"
    TOTAL_KEYS=$(redis-cli DBSIZE 2>/dev/null || echo "unknown")
    MEMORY_USAGE=$(redis-cli INFO memory 2>/dev/null | grep used_memory_human | cut -d: -f2 | tr -d '\r' || echo "unknown")
    echo "  • Total keys: $TOTAL_KEYS"
    echo "  • Memory usage: $MEMORY_USAGE"
    
    echo ""
    echo "💡 Cache Invalidation Tips:"
    echo "  • Use consistent cache key naming patterns"
    echo "  • Consider cache TTL for automatic expiration"
    echo "  • Monitor cache hit/miss ratios"
    echo "  • Use Redis keyspace notifications for advanced invalidation"
    
    echo ""
    echo "🎯 Cache invalidation complete!"
    
elif [[ "$FILE_PATH" == *config/*.* ]] || [[ "$FILE_PATH" == *.env ]]; then
    echo "⚙️ Configuration file detected - consider full cache flush if needed"
    echo "💡 Run 'redis-cli FLUSHDB' manually if configuration affects cached data"
    
else
    echo "ℹ️ File does not require cache invalidation: $FILE_PATH"
fi

exit 0

Use Cases

Common scenarios and applications

Invalidate cache when data models are modified
Maintain cache consistency in Redis
Clear related cache entries automatically
Prevent stale data in cache after model changes
Optimize cache management workflow
Handle cache invalidation for microservices
Automate cache clearing for API responses
Ensure data consistency across cache layers

Troubleshooting

Common issues and solutions

Hook skips invalidation with redis-cli not found warning
Install Redis CLI tools using 'apt-get install redis-tools' (Ubuntu/Debian) or 'brew install redis' (macOS). The hook gracefully exits if Redis tools are unavailable.
Redis server not accessible error during invalidation
Verify Redis is running with 'redis-cli ping'. Check connection settings in redis.conf. The hook tests connectivity before attempting invalidation and exits safely if unreachable.
Too many or too few cache keys being invalidated
Review cache key naming patterns. The hook uses wildcard matching on model names. Use consistent prefixes like 'api:', 'query:', 'model:' for precise pattern matching and control.
Hook triggers on non-model files causing unnecessary scans
The hook only processes files in */models/*, */schemas/*, */entities/* directories. Organize your codebase to match these patterns or customize the path matching logic in the script.
Cache invalidation completes but stale data persists
Check if your application uses multiple Redis databases (DB0, DB1, etc.) or instances. The hook targets the default database. Use 'redis-cli -n <db>' to verify which database stores your cache.

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