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FinFocus Documentation

System Architecture Diagram

This diagram shows the high-level architecture of FinFocus, including all major components and their relationships.

graph TB
    subgraph "User Interface"
        CLI[CLI Layer<br/>internal/cli]
    end


    subgraph "Core System"
        Engine[Engine<br/>internal/engine<br/>Cost Orchestration]
        Ingest[Ingest<br/>internal/ingest<br/>Pulumi JSON Parser]
        Registry[Registry<br/>internal/registry<br/>Plugin Discovery]
    end


    subgraph "Plugin System"
        PluginHost[Plugin Host<br/>internal/pluginhost<br/>gRPC Client Manager]
        Plugin1[Plugin: Kubecost]
        Plugin2[Plugin: Vantage]
        Plugin3[Plugin: Custom]
    end


    subgraph "Fallback System"
        SpecLoader[Spec Loader<br/>internal/spec<br/>YAML Parser]
        SpecFiles[(Local Pricing Specs<br/>~/.finfocus/specs/)]
    end


    subgraph "External Systems"
        PulumiCLI[Pulumi CLI<br/>pulumi preview --json]
        KubecostAPI[Kubecost API]
        VantageAPI[Vantage API]
        CloudAPIs[Cloud Provider APIs]
    end


    subgraph "Plugin Storage"
        PluginDir[(Plugin Binaries<br/>~/.finfocus/plugins/)]
    end


    CLI --> Engine
    Engine --> Ingest
    Engine --> PluginHost
    Engine --> SpecLoader


    Ingest --> PulumiCLI


    PluginHost --> Registry
    Registry --> PluginDir
    PluginHost --> Plugin1
    PluginHost --> Plugin2
    PluginHost --> Plugin3


    Plugin1 -.gRPC.-> KubecostAPI
    Plugin2 -.gRPC.-> VantageAPI
    Plugin3 -.gRPC.-> CloudAPIs


    SpecLoader --> SpecFiles


    classDef coreComponent fill:#4A90E2,stroke:#2E5C8A,color:#fff
    classDef pluginComponent fill:#7ED321,stroke:#5A9E19,color:#fff
    classDef storage fill:#F5A623,stroke:#C77F1B,color:#fff
    classDef external fill:#BD10E0,stroke:#8B0AA8,color:#fff


    class CLI,Engine,Ingest,Registry coreComponent
    class PluginHost,Plugin1,Plugin2,Plugin3 pluginComponent
    class SpecLoader,SpecFiles,PluginDir storage
    class PulumiCLI,KubecostAPI,VantageAPI,CloudAPIs external

Component Overview

Section titled “Component Overview”

User Interface Layer

Section titled “User Interface Layer”
  • CLI Layer (internal/cli) - Cobra-based command-line interface providing subcommands for cost operations and plugin management

Core System Components

Section titled “Core System Components”
  • Engine (internal/engine) - Orchestrates cost calculations, coordinates between plugins and specs, handles output formatting
  • Ingest (internal/ingest) - Parses Pulumi JSON output and converts to resource descriptors
  • Registry (internal/registry) - Discovers and manages plugin lifecycle from filesystem

Plugin System

Section titled “Plugin System”
  • Plugin Host (internal/pluginhost) - Manages gRPC connections to plugins, handles process lifecycle
  • Plugins - External cost source integrations (Kubecost, Vantage, custom implementations)

Fallback System

Section titled “Fallback System”
  • Spec Loader (internal/spec) - Loads local YAML pricing specifications when plugins unavailable
  • Spec Files - Local YAML-based pricing data stored in user’s home directory

External Systems

Section titled “External Systems”
  • Pulumi CLI - Generates infrastructure plan JSON via pulumi preview --json
  • Cost Source APIs - External APIs (Kubecost, Vantage, cloud providers) queried by plugins

Communication Patterns

Section titled “Communication Patterns”
  • Solid lines - Direct function calls and synchronous communication
  • Dotted lines - gRPC network communication with external APIs
  • Storage cylinders - Filesystem-based data sources

Design Patterns

Section titled “Design Patterns”
  • Plugin Architecture - Extensible via external gRPC plugins
  • Fallback Pattern - Local specs used when plugins unavailable
  • Registry Pattern - Dynamic plugin discovery from filesystem
  • Adapter Pattern - Engine adapts between CLI, plugins, and specs

Related Documentation: