Building Production-Ready RAG Systems in Go
KodeNimbus Team • Golang

Building Production-Ready RAG Systems in Go

December 2, 2025

Retrieval-Augmented Generation (RAG) has become the go-to architecture for building AI applications that need to access external knowledge. While Python dominates the AI tooling landscape, Go offers compelling advantages for production RAG systems: superior performance, built-in concurrency, small memory footprint, and excellent deployment characteristics.

In this guide, we'll explore how to build a production-ready RAG system in Go, covering everything from core data structures to deployment considerations.


Why Go for RAG?

Before diving into implementation, let's understand why Go makes sense for RAG systems:


  • Performance: Go's compiled nature and efficient garbage collector handle high-throughput vector operations better than interpreted languages

  • Concurrency: Native goroutines make parallel document processing and batch embedding generation straightforward
  • Deployment: Single binary deployment with no runtime dependencies simplifies operations
  • Resource efficiency: Lower memory footprint means better cost efficiency at scale
  • Type safety: Strong typing catches errors at compile time, crucial for production systems


Core Architecture

A production RAG system consists of several key components:

User Query → Query Processing → Vector Search → Context Ranking → LLM Generation → Response
                ↓                      ↓
          Document Pipeline    Vector Database


Essential Data Structures

Let's start with the foundational data structures for our RAG system:

package rag

import (
    "context"
    "time"
)

// Document represents a source document in the RAG system
type Document struct {
    ID          string            `json:"id"`
    Content     string            `json:"content"`
    Metadata    map[string]any    `json:"metadata"`
    Source      string            `json:"source"`
    CreatedAt   time.Time         `json:"created_at"`
    UpdatedAt   time.Time         `json:"updated_at"`
}

// Chunk represents a processed chunk of a document
type Chunk struct {
    ID          string            `json:"id"`
    DocumentID  string            `json:"document_id"`
    Content     string            `json:"content"`
    Embedding   []float32         `json:"embedding,omitempty"`
    Position    int               `json:"position"`
    Metadata    map[string]any    `json:"metadata"`
    TokenCount  int               `json:"token_count"`
}

// SearchResult represents a retrieved chunk with relevance score
type SearchResult struct {
    Chunk       *Chunk   `json:"chunk"`
    Score       float32  `json:"score"`
    Rank        int      `json:"rank"`
}

// RAGRequest encapsulates a user query
type RAGRequest struct {
    Query       string            `json:"query"`
    TopK        int               `json:"top_k"`
    Filters     map[string]any    `json:"filters,omitempty"`
    Context     context.Context   `json:"-"`
}

// RAGResponse contains the generated response and sources
type RAGResponse struct {
    Answer      string           `json:"answer"`
    Sources     []SearchResult   `json:"sources"`
    Latency     time.Duration    `json:"latency"`
    TokensUsed  int              `json:"tokens_used"`
}



Document Processing Pipeline

The ingestion pipeline is critical for RAG quality. Here's a robust implementation:

// DocumentProcessor handles document ingestion and chunking
type DocumentProcessor struct {
    chunkSize     int
    chunkOverlap  int
    embedder      Embedder
    vectorStore   VectorStore
}

func NewDocumentProcessor(chunkSize, overlap int, embedder Embedder, store VectorStore) *DocumentProcessor {
    return &DocumentProcessor{
        chunkSize:    chunkSize,
        chunkOverlap: overlap,
        embedder:     embedder,
        vectorStore:  store,
    }
}

// ProcessDocument handles the complete document processing pipeline
func (dp *DocumentProcessor) ProcessDocument(ctx context.Context, doc *Document) error {
    // 1. Chunk the document
    chunks := dp.chunkDocument(doc)
    
    // 2. Generate embeddings in parallel
    if err := dp.generateEmbeddings(ctx, chunks); err != nil {
        return fmt.Errorf("embedding generation failed: %w", err)
    }
    
    // 3. Store in vector database
    if err := dp.vectorStore.UpsertChunks(ctx, chunks); err != nil {
        return fmt.Errorf("vector store upsert failed: %w", err)
    }
    
    return nil
}

// chunkDocument splits a document into overlapping chunks
func (dp *DocumentProcessor) chunkDocument(doc *Document) []*Chunk {
    content := doc.Content
    chunks := make([]*Chunk, 0)
    position := 0
    
    for i := 0; i < len(content); i += (dp.chunkSize - dp.chunkOverlap) {
        end := i + dp.chunkSize
        if end > len(content) {
            end = len(content)
        }
        
        chunk := &Chunk{
            ID:         fmt.Sprintf("%s_chunk_%d", doc.ID, position),
            DocumentID: doc.ID,
            Content:    content[i:end],
            Position:   position,
            Metadata:   doc.Metadata,
        }
        
        chunks = append(chunks, chunk)
        position++
        
        if end >= len(content) {
            break
        }
    }
    
    return chunks
}

// generateEmbeddings creates embeddings for chunks in parallel
func (dp *DocumentProcessor) generateEmbeddings(ctx context.Context, chunks []*Chunk) error {
    const batchSize = 10
    errChan := make(chan error, len(chunks))
    semaphore := make(chan struct{}, batchSize)
    
    var wg sync.WaitGroup
    
    for _, chunk := range chunks {
        wg.Add(1)
        go func(c *Chunk) {
            defer wg.Done()
            semaphore <- struct{}{}
            defer func() { <-semaphore }()
            
            embedding, err := dp.embedder.Embed(ctx, c.Content)
            if err != nil {
                errChan <- err
                return
            }
            
            c.Embedding = embedding
        }(chunk)
    }
    
    wg.Wait()
    close(errChan)
    
    if err := <-errChan; err != nil {
        return err
    }
    
    return nil
}


Vector Search Interface

Define clean interfaces for vector storage and retrieval:

// VectorStore defines the interface for vector database operations
type VectorStore interface {
    UpsertChunks(ctx context.Context, chunks []*Chunk) error
    Search(ctx context.Context, query []float32, topK int, filters map[string]any) ([]SearchResult, error)
    Delete(ctx context.Context, documentID string) error
    HealthCheck(ctx context.Context) error
}

// Embedder defines the interface for generating embeddings
type Embedder interface {
    Embed(ctx context.Context, text string) ([]float32, error)
    EmbedBatch(ctx context.Context, texts []string) ([][]float32, error)
    Dimensions() int
}


RAG Orchestrator

The orchestrator ties everything together:

// RAGSystem orchestrates the complete RAG pipeline
type RAGSystem struct {
    embedder     Embedder
    vectorStore  VectorStore
    llmClient    LLMClient
    processor    *DocumentProcessor
}

func NewRAGSystem(embedder Embedder, store VectorStore, llm LLMClient) *RAGSystem {
    return &RAGSystem{
        embedder:    embedder,
        vectorStore: store,
        llmClient:   llm,
        processor:   NewDocumentProcessor(512, 50, embedder, store),
    }
}

// Query processes a RAG query end-to-end
func (rs *RAGSystem) Query(ctx context.Context, req *RAGRequest) (*RAGResponse, error) {
    start := time.Now()
    
    // 1. Embed the query
    queryEmbedding, err := rs.embedder.Embed(ctx, req.Query)
    if err != nil {
        return nil, fmt.Errorf("query embedding failed: %w", err)
    }
    
    // 2. Search vector store
    results, err := rs.vectorStore.Search(ctx, queryEmbedding, req.TopK, req.Filters)
    if err != nil {
        return nil, fmt.Errorf("vector search failed: %w", err)
    }
    
    // 3. Build context from results
    context := rs.buildContext(results)
    
    // 4. Generate response with LLM
    answer, tokens, err := rs.llmClient.Generate(ctx, req.Query, context)
    if err != nil {
        return nil, fmt.Errorf("LLM generation failed: %w", err)
    }
    
    return &RAGResponse{
        Answer:     answer,
        Sources:    results,
        Latency:    time.Since(start),
        TokensUsed: tokens,
    }, nil
}

// buildContext constructs the context string from search results
func (rs *RAGSystem) buildContext(results []SearchResult) string {
    var builder strings.Builder
    builder.WriteString("Use the following context to answer the question:\n\n")
    
    for i, result := range results {
        builder.WriteString(fmt.Sprintf("Source %d (relevance: %.2f):\n", i+1, result.Score))
        builder.WriteString(result.Chunk.Content)
        builder.WriteString("\n\n")
    }
    
    return builder.String()
}


Production Considerations

1. Error Handling and Retries

type RetryConfig struct {
    MaxAttempts int
    InitialDelay time.Duration
    MaxDelay time.Duration
    Multiplier float64
}

func withRetry(ctx context.Context, cfg RetryConfig, fn func() error) error {
    delay := cfg.InitialDelay
    
    for attempt := 0; attempt < cfg.MaxAttempts; attempt++ {
        if err := fn(); err == nil {
            return nil
        } else if !isRetryable(err) {
            return err
        }
        
        select {
        case <-ctx.Done():
            return ctx.Err()
        case <-time.After(delay):
            delay = time.Duration(float64(delay) * cfg.Multiplier)
            if delay > cfg.MaxDelay {
                delay = cfg.MaxDelay
            }
        }
    }
    
    return fmt.Errorf("max retry attempts exceeded")
}


2. Monitoring and Observability

type Metrics struct {
    QueryLatency      prometheus.Histogram
    EmbeddingLatency  prometheus.Histogram
    SearchLatency     prometheus.Histogram
    LLMLatency        prometheus.Histogram
    ErrorCount        prometheus.Counter
    RequestCount      prometheus.Counter
}

func (rs *RAGSystem) QueryWithMetrics(ctx context.Context, req *RAGRequest) (*RAGResponse, error) {
    rs.metrics.RequestCount.Inc()
    
    start := time.Now()
    response, err := rs.Query(ctx, req)
    
    if err != nil {
        rs.metrics.ErrorCount.Inc()
        return nil, err
    }
    
    rs.metrics.QueryLatency.Observe(time.Since(start).Seconds())
    return response, nil
}


3. Caching Layer

type CachedRAGSystem struct {
    *RAGSystem
    cache Cache
    ttl   time.Duration
}

func (crs *CachedRAGSystem) Query(ctx context.Context, req *RAGRequest) (*RAGResponse, error) {
    cacheKey := fmt.Sprintf("rag:%s", hashQuery(req))
    
    // Check cache
    if cached, found := crs.cache.Get(cacheKey); found {
        return cached.(*RAGResponse), nil
    }
    
    // Execute query
    response, err := crs.RAGSystem.Query(ctx, req)
    if err != nil {
        return nil, err
    }
    
    // Cache result
    crs.cache.Set(cacheKey, response, crs.ttl)
    
    return response, nil
}


Testing Strategy

func TestRAGSystem(t *testing.T) {
    // Use test doubles
    mockEmbedder := &MockEmbedder{}
    mockStore := &MockVectorStore{}
    mockLLM := &MockLLMClient{}
    
    system := NewRAGSystem(mockEmbedder, mockStore, mockLLM)
    
    t.Run("successful query", func(t *testing.T) {
        ctx := context.Background()
        req := &RAGRequest{
            Query: "What is RAG?",
            TopK:  5,
        }
        
        mockEmbedder.On("Embed", ctx, req.Query).Return([]float32{0.1, 0.2}, nil)
        mockStore.On("Search", ctx, mock.Anything, 5, mock.Anything).Return([]SearchResult{}, nil)
        mockLLM.On("Generate", ctx, mock.Anything, mock.Anything).Return("RAG is...", 100, nil)
        
        response, err := system.Query(ctx, req)
        
        assert.NoError(t, err)
        assert.NotNil(t, response)
        assert.Greater(t, response.TokensUsed, 0)
    })
}


Deployment Architecture

For production deployment, consider this architecture:

┌─────────────┐
│   Load      │
│   Balancer  │
└──────┬──────┘
       │
   ┌───┴────┐
   │  API   │ ← Go RAG Service (multiple instances)
   │ Gateway│
   └───┬────┘
       │
   ┌───┴─────────────────┐
   │                     │
┌──▼───────┐      ┌─────▼──────┐
│  Vector  │      │    LLM     │
│   DB     │      │   Service  │
│(Pinecone/│      │  (OpenAI)  │
│ Weaviate)│      └────────────┘
└──────────┘


Performance Optimization Tips

  1. Batch embedding generation: Process multiple documents in parallel
  2. Connection pooling: Reuse HTTP connections to external services
  3. Async processing: Use background workers for document ingestion
  4. Index optimization: Tune vector database index parameters for your workload
  5. Context window management: Implement smart context truncation for large result sets


Conclusion

Building production-ready RAG systems in Go offers significant advantages in performance, reliability, and operational simplicity. The combination of strong typing, excellent concurrency primitives, and efficient resource utilization makes Go an excellent choice for RAG deployments at scale.

The data structures and patterns outlined here provide a solid foundation for building robust RAG systems. Remember to focus on observability, error handling, and testing to ensure your system performs reliably in production.

Next Steps

  • Implement hybrid search (combining dense and sparse retrieval)
  • Add re-ranking models for improved relevance
  • Explore query expansion techniques
  • Implement user feedback loops for continuous improvement
  • Add support for multimodal RAG (text + images)

Happy building!

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