README
¶
Apache Answer Plugin: ChromaDB Vector Search
This plugin enables semantic/vector search in Apache Answer using ChromaDB.
Prerequisites
- ChromaDB instance (self-hosted)
- An OpenAI-compatible embedding API (e.g., OpenAI, Azure OpenAI, or any compatible provider)
Installation
Build Apache Answer with this plugin:
./answer build --with github.com/apache/answer-plugins/vector-search-chromadb
Configuration
After enabling the plugin in the Admin UI (Admin > Plugins > Vector Search), configure the following fields:
| Field | Description | Example |
|---|---|---|
| ChromaDB Endpoint | ChromaDB HTTP API URL | http://localhost:8000 |
| Embedding API Host | OpenAI-compatible API base URL | https://api.openai.com |
| Embedding API Key | API key for the embedding service | sk-... |
| Embedding Model | Model name for generating embeddings | text-embedding-3-small |
| Embedding Level | question embeds question + all answers + comments together; answer embeds each answer separately |
question |
| Similarity Threshold | Minimum cosine similarity score (0-1). Default 0 means no filtering |
0.5 |
How It Works
- Embedding dimensions are auto-detected from the configured model. No manual dimension configuration is needed.
- On first configuration, the plugin creates a collection
answer_vector_embeddingswithhnsw:spaceset to cosine. - Uses the ChromaDB REST API directly (no external Go SDK required).
- ChromaDB cosine distance (0 = identical, 2 = opposite) is converted to a similarity score (1.0 = identical, 0.0 = opposite).
- A full sync of all questions/answers is triggered when the plugin starts.
Running ChromaDB Locally
Using Docker:
docker run -p 8000:8000 chromadb/chroma
The REST API will be available at http://localhost:8000.
License
Documentation
¶
Index ¶
- Variables
- type VectorSearchConfig
- type VectorSearchEngine
- func (e *VectorSearchEngine) ConfigFields() []plugin.ConfigField
- func (e *VectorSearchEngine) ConfigReceiver(config []byte) error
- func (e *VectorSearchEngine) DeleteContent(ctx context.Context, objectID string) error
- func (e *VectorSearchEngine) Description() plugin.VectorSearchDesc
- func (e *VectorSearchEngine) Info() plugin.Info
- func (e *VectorSearchEngine) RegisterSyncer(ctx context.Context, syncer plugin.VectorSearchSyncer)
- func (e *VectorSearchEngine) SearchSimilar(ctx context.Context, query string, topK int) ([]plugin.VectorSearchResult, error)
- func (e *VectorSearchEngine) UpdateContent(ctx context.Context, content *plugin.VectorSearchContent) error
Constants ¶
This section is empty.
Variables ¶
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var Info embed.FS
Functions ¶
This section is empty.
Types ¶
type VectorSearchConfig ¶
type VectorSearchConfig struct {
Endpoint string `json:"endpoint"`
APIHost string `json:"api_host"`
APIKey string `json:"api_key"`
EmbeddingModel string `json:"embedding_model"`
EmbeddingLevel string `json:"embedding_level"`
SimilarityThreshold float64 `json:"similarity_threshold"`
}
VectorSearchConfig holds all plugin configuration.
type VectorSearchEngine ¶
type VectorSearchEngine struct {
Config *VectorSearchConfig
// contains filtered or unexported fields
}
VectorSearchEngine implements plugin.VectorSearch using ChromaDB REST API.
func (*VectorSearchEngine) ConfigFields ¶
func (e *VectorSearchEngine) ConfigFields() []plugin.ConfigField
ConfigFields returns the plugin configuration form fields.
func (*VectorSearchEngine) ConfigReceiver ¶
func (e *VectorSearchEngine) ConfigReceiver(config []byte) error
ConfigReceiver applies configuration from the admin UI.
func (*VectorSearchEngine) DeleteContent ¶
func (e *VectorSearchEngine) DeleteContent(ctx context.Context, objectID string) error
DeleteContent removes a document by object ID.
func (*VectorSearchEngine) Description ¶
func (e *VectorSearchEngine) Description() plugin.VectorSearchDesc
Description returns metadata about this vector search engine.
func (*VectorSearchEngine) Info ¶
func (e *VectorSearchEngine) Info() plugin.Info
func (*VectorSearchEngine) RegisterSyncer ¶
func (e *VectorSearchEngine) RegisterSyncer(ctx context.Context, syncer plugin.VectorSearchSyncer)
RegisterSyncer stores the syncer and triggers a full sync.
func (*VectorSearchEngine) SearchSimilar ¶
func (e *VectorSearchEngine) SearchSimilar(ctx context.Context, query string, topK int) ([]plugin.VectorSearchResult, error)
SearchSimilar performs a cosine similarity search via ChromaDB REST API.
func (*VectorSearchEngine) UpdateContent ¶
func (e *VectorSearchEngine) UpdateContent(ctx context.Context, content *plugin.VectorSearchContent) error
UpdateContent upserts a single document via ChromaDB REST API.
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