Migrates the AMP module to a new unified routing system, replacing the fallback handler with a router-based approach.
This change introduces a `ModelRoutingWrapper` that handles model extraction, routing decisions, and proxying based on provider availability and model mappings.
It provides a more flexible and maintainable routing mechanism by centralizing routing logic.
The changes include:
- Introducing new `routing` package with core routing logic.
- Creating characterization tests to capture existing behavior.
- Implementing model extraction and rewriting.
- Updating AMP module routes to utilize the new routing wrapper.
- Deprecating `FallbackHandler` in favor of the new `ModelRoutingWrapper`.
Improves AMP request handling by consolidating model mapping logic into a helper function for better readability and maintainability.
Enhances error handling for premature client connection closures during reverse proxy operations by explicitly acknowledging and swallowing the ErrAbortHandler panic, preventing noisy stack traces.
Removes unused method `findProviderViaOAuthAlias` from the `DefaultModelMapper`.
Enhances the AMP model mapping functionality to support fallback mechanisms using .
This change allows the system to attempt alternative models (aliases) if the primary mapped model fails due to issues like quota exhaustion. It updates the model mapper to load and utilize the configuration, enabling provider lookup via aliases. It also introduces context keys to pass fallback model names between handlers.
Additionally, this change introduces a fix to prevent ReverseProxy from panicking by swallowing ErrAbortHandler panics.
Amp-Thread-ID: https://ampcode.com/threads/T-019c0cd1-9e59-722b-83f0-e0582aba6914
Co-authored-by: Amp <amp@ampcode.com>
This commit introduces several improvements to the AMP (Advanced Model Proxy) module:
- **Model Mapping Logic:** The `FallbackHandler` now uses a more robust approach for model mapping. It includes the extraction and preservation of dynamic "thinking suffixes" (e.g., `(xhigh)`) during mapping, ensuring that these configurations are correctly applied to the mapped model. A new `resolveMappedModel` function centralizes this logic for cleaner code.
- **ModelMapper Verification:** The `ModelMapper` in `model_mapping.go` now verifies that the target model of a mapping has available providers *after* normalizing it. This prevents mappings to non-existent or unresolvable models.
- **Gemini Thinking Configuration Cleanup:** In `gemini_thinking.go`, unnecessary `generationConfig.thinkingConfig.include_thoughts` and `generationConfig.thinkingConfig.thinkingBudget` fields are now deleted from the request body when applying Gemini thinking levels. This prevents potential conflicts or redundant configurations.
- **Testing:** A new test case `TestModelMapper_MapModel_TargetWithThinkingSuffix` has been added to `model_mapping_test.go` to specifically cover the preservation of thinking suffixes during model mapping.
- Add AmpModelMapping config to route models like 'claude-opus-4.5' to 'claude-sonnet-4'
- Add ModelMapper interface and DefaultModelMapper implementation with hot-reload support
- Enhance FallbackHandler to apply model mappings before falling back to ampcode.com
- Add structured logging for routing decisions (local provider, mapping, amp credits)
- Update config.example.yaml with amp-model-mappings documentation
