Package com.google.genkit.core.middleware

Class CommonMiddleware

java.lang.Object
com.google.genkit.core.middleware.CommonMiddleware
public final class CommonMiddleware extends Object
CommonMiddleware provides factory methods for creating commonly-used middleware functions.

  • Method Details

    • logging

      public static <I, O> Middleware<I,O> logging(String name)
      Creates a logging middleware that logs requests and responses.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      name - the name to use in log messages
      Returns:
      a logging middleware

    • logging

      public static <I, O> Middleware<I,O> logging(String name, org.slf4j.Logger customLogger)
      Creates a logging middleware with a custom logger.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      name - the name to use in log messages
      customLogger - the logger to use
      Returns:
      a logging middleware

    • timing

      public static <I, O> Middleware<I,O> timing(Consumer<Long> callback)
      Creates a timing middleware that measures execution time.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      callback - callback to receive timing information (duration in milliseconds)
      Returns:
      a timing middleware

    • retry

      public static <I, O> Middleware<I,O> retry(int maxRetries, long initialDelayMs)
      Creates a retry middleware with exponential backoff.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      maxRetries - maximum number of retry attempts
      initialDelayMs - initial delay between retries in milliseconds
      Returns:
      a retry middleware

    • retry

      public static <I, O> Middleware<I,O> retry(int maxRetries, long initialDelayMs, Function<GenkitException,Boolean> shouldRetry)
      Creates a retry middleware with exponential backoff and custom retry predicate.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      maxRetries - maximum number of retry attempts
      initialDelayMs - initial delay between retries in milliseconds
      shouldRetry - predicate to determine if an exception should trigger a retry
      Returns:
      a retry middleware

    • validate

      public static <I, O> Middleware<I,O> validate(Consumer<I> validator)
      Creates a validation middleware that validates the request before processing.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      validator - the validation function (throws GenkitException on invalid input)
      Returns:
      a validation middleware

    • transformRequest

      public static <I, O> Middleware<I,O> transformRequest(Function<I,I> transformer)
      Creates a transformation middleware that transforms the request before processing.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      transformer - the transformation function
      Returns:
      a transformation middleware

    • transformResponse

      public static <I, O> Middleware<I,O> transformResponse(Function<O,O> transformer)
      Creates a transformation middleware that transforms the response after processing.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      transformer - the transformation function
      Returns:
      a transformation middleware

    • cache

      public static <I, O> Middleware<I,O> cache(MiddlewareCache<O> cache, Function<I,String> keyExtractor)
      Creates a caching middleware that caches results based on a key.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      cache - the cache implementation
      keyExtractor - function to extract cache key from request
      Returns:
      a caching middleware

    • errorHandler

      public static <I, O> Middleware<I,O> errorHandler(Function<GenkitException,O> errorHandler)
      Creates an error handling middleware that catches and transforms exceptions.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      errorHandler - the error handler function
      Returns:
      an error handling middleware

    • conditional

      public static <I, O> Middleware<I,O> conditional(BiPredicate<I,ActionContext> predicate, Middleware<I,O> middleware)
      Creates a conditional middleware that only applies if the predicate is true.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      predicate - the condition to check
      middleware - the middleware to apply if condition is true
      Returns:
      a conditional middleware

    • beforeAfter

      public static <I, O> Middleware<I,O> beforeAfter(BiConsumer<I,ActionContext> before, BiConsumer<O,ActionContext> after)
      Creates a before/after middleware that runs callbacks before and after execution.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      before - callback to run before execution
      after - callback to run after execution
      Returns:
      a before/after middleware

    • rateLimit

      public static <I, O> Middleware<I,O> rateLimit(int maxRequests, long windowMs)
      Creates a rate limiting middleware (simple token bucket implementation).
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      maxRequests - maximum requests allowed in the time window
      windowMs - time window in milliseconds
      Returns:
      a rate limiting middleware

    • timeout

      public static <I, O> Middleware<I,O> timeout(long timeoutMs)
      Creates a timeout middleware that throws an exception if execution takes too long.
      Type Parameters:
      I - input type
      O - output type
      Parameters:
      timeoutMs - timeout in milliseconds
      Returns:
      a timeout middleware