- feat(router-filter): add gRPC filter stream protocol and hub

[wilsonwang371]

This pull request introduces several new features and improvements focused on agent support, configuration enhancements, build process updates, and documentation clarity. The most important changes include adding a new keyword-filter-agent binary and related build targets, expanding configuration options for file storage and router filter streaming, updating dependencies and build scripts, and improving documentation for credential handling and model provisioning.

Agent Support and Build Process

• Added a new keyword-filter-agent binary (src/apps/keyword_filter_agent/main.rs) and integrated build targets in the Makefile for both debug and release builds, along with Docker entrypoints for agent containers. [1] [2] [3]
• Updated .dockerignore to exclude build artifacts, logs, and unnecessary files for cleaner Docker builds.

Configuration Enhancements

• Introduced new configuration fields for file storage (files_dir, execution_logs_dir) in various config.toml files, and added local_models_dir and extensive router filter stream settings in config/spearlet/config.toml. [1] [2] [3] [4] [5] [6] [7]
• Updated LLM backend configuration to require hosting and optionally use credential_ref for environment variable binding, with improved filtering logic. [1] [2]

Dependency and Build Script Updates

• Upgraded tower dependency from 0.4 to 0.5 and improved reqwest configuration for TLS support. [1] [2]
• Enhanced Cross.toml to use a specific image hash and install additional build dependencies for cross-compilation.
• Added new proto file (proto/spearlet/router_filter.proto) to the build script for code generation.

Documentation Improvements

• Clarified credential handling and LLM backend configuration in both English and Chinese README files, including details on model provisioning and download parameters. [1] [2] [3] [4]

Makefile and Sample Updates

• Expanded Makefile targets for agent builds, E2E testing (including Docker and kind+Helm), and added new WASM JS sample for router filter keyword. [1] [2] [3] [4] [5] [6]

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Agent and Build Process

• Added keyword-filter-agent binary and build targets, including Docker entrypoints for agent containers. [1] [2] [3]
• Updated .dockerignore to exclude unnecessary files for Docker builds.

Configuration Enhancements

• Introduced files_dir, execution_logs_dir, local_models_dir, and extensive router filter stream settings in configuration files. [1] [2] [3] [4] [5] [6] [7]
• Improved LLM backend configuration with required hosting and optional credential_ref for environment variable binding. [1] [2]

Dependency and Build Script Updates

• Upgraded tower to 0.5, improved reqwest TLS support, and enhanced cross-compilation setup in Cross.toml. [1] [2] [3]
• Added proto/spearlet/router_filter.proto to build script for code generation.

Documentation Improvements

• Clarified credential handling and LLM backend configuration in README files, including model provisioning details. [1] [2] [3] [4]

Makefile and Sample Updates

• Expanded Makefile targets for agent builds and E2E testing, and added new WASM JS sample for router filter keyword. [1] [2] [3] [4] [5] [6]

• feat(apps): add keyword-based router filter agent

• feat(config): require llm backend hosting to be local|remote

• docs: align llm backend docs with hosting and credential_ref

• feat(deploy): add helm chart and docker entrypoints

• fix(samples): avoid reassigning const in router_filter_keyword