Otter 🦦

Under construction 🚧

Built for performance. Designed for graphs.

Otter is a lightweight, purpose-driven proxy and query transpiler for Dgraph.
It intelligently balances traffic between Dgraph clusters and adds support for advanced query workflows — including Cypher-to-DQL translation (in progress).

Otter aims to serve as the foundation for future support of multiple graph languages, offering modular extensions, semantic enrichment, and introspection tools.

Why this Software?

Read Why this software was created.

---

Otter Design

Current design.

Features

• Round-robin and purpose-based balancing
• HTTP proxy for Dgraph /query and /mutate
• WebSocket server with support for query, mutation, and upsert
• Simple token-based authentication
• Configurable via environment variables or YAML
• Otter now supports GraphQL queries via Ratel. Just enable the experimental feature ratel-graphql: true

---

Run Otter with Docker

Requirements

• Clone the repository

• Docker

• Docker Compose

• (optional) make installed

Run with make

make rund

Manual Docker Compose If you don't have make:

cd examples/cluster
docker compose up --build

Configuration

By default, Otter will load config from:

CONFIG_FILE=/app/manifest/config_docker.yaml

If you want to change the config:

manifest/config_docker.yaml

Or override with environment variables (see internal/config/config.go for supported vars)

---

Example WebSocket Payload

{
  "type": "upsert",
  "query": "query { u as var(func: eq(email, \"[email protected]\")) }",
  "mutation": "uid(u) <name> \"Test\" .",
  "cond": "@if(eq(len(u), 1))",
  "commitNow": true
}

---

Run Locally

git clone https://github.com/OpenDgraph/Otter.git
cd Otter

export CONFIG_FILE=./manifest/config.yaml
go run cmd/proxy/main.go

Set your balancer strategy inside config.yaml:

balancer_type: purposeful # or round-robin

---

HTTP Proxy Endpoints

Endpoint	Method	Description
/query	POST	Executes a DQL query
/mutate	POST	Executes a mutation

Supported Content-Types:

• application/json
• application/dql

Example request:

curl -X POST http://localhost:8080/query \
  -H "Content-Type: application/json" \
  -d '{"query": "{ data(func: has(email)) { uid name email } }"}'

---

---

WebSocket Usage

URL: ws://localhost:8089/ws

Supported message types:

• auth -> authenticate
• ping -> keep connection alive
• query / mutation / upsert → require authentication

Example (after auth):

{
  "type": "query",
  "query": "{ data(func: has(email)) { uid name email } }",
  "token": "banana",
  "verbose": true
}

Load Balancing Modes

Available types:

• round-robin (default)
• defined (per-purpose: query/mutation/upsert)

To use defined, provide a YAML like this:

balancer_type: defined
groups:
  query:
    - localhost:9080
  mutation:
    - localhost:9081
  upsert:
    - localhost:9082

---

Roadmap

• Automatic health checks
• Support for multiple Balancing strategies
• Graph model abstraction
• Become a framework

More purposeful Balancing strategies:

• round-robin basic round-robin
• round-robin-purposeful with purpose
• round-robin-healthy support
• round-robin-on-RW separate readonly and write only
• round-robin-avoid-leaders avoid leaders
• round-robin-leaders-only leaders only
• round-robin-state-based this will check the state of the Alpha and check memory usage and coroutine count

---