Configuration Reference

Authoritative reference for Drasi Server configuration (server + instance settings)

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Configuration Reference

This page is the authoritative reference for the Drasi Server configuration file itself.

It covers:

Server-level settings (host/port/logging/persistence)
Instance settings for the embedded DrasiLib runtime (single instance or instances: multi-instance mode)

It does not document the per-component configuration for Sources, Queries, Reactions, or Bootstrap Providers (those have dedicated pages).

Quick Reference

Field	Type	Default	Description
`id`	string	UUID	Server/instance identifier
`host`	string	`0.0.0.0`	API bind address
`port`	integer	`8080`	API port
`logLevel`	string	`info`	`trace`, `debug`, `info`, `warn`, `error`
`persistConfig`	boolean	`true`	Save API changes to config file
`persistIndex`	boolean	`false`	Use persistent RocksDB indexes
`stateStore`	object	None	Plugin state persistence
`defaultPriorityQueueCapacity`	integer	None	Default queue size
`defaultDispatchBufferCapacity`	integer	None	Default buffer size
`sources`	array	`[]`	Source configurations
`queries`	array	`[]`	Query configurations
`reactions`	array	`[]`	Reaction configurations
`instances`	array	`[]`	Multi-instance configurations

Key rules

Config is YAML or JSON.
Keys are strictly camelCase and unknown fields are rejected.
Many scalar values support environment variable interpolation (see below).

File location

Default path: config/server.yaml

Override with:

drasi-server --config /path/to/server.yaml

Port override

You can override the configured port at runtime with `--port`. The config file still remains the source of truth for the persisted configuration.

Minimal Configuration

# Smallest useful config - mock source with log output
host: 0.0.0.0
port: 8080

sources:
  - kind: mock
    id: test
    dataType: sensor_reading

queries:
  - id: all-data
    query: "MATCH (n) RETURN n"
    sources:
      - sourceId: test
    autoStart: true

reactions:
  - kind: log
    id: console
    queries: [all-data]
    autoStart: true

Full Configuration Example

# Complete production-ready configuration
id: production-server
host: 0.0.0.0
port: ${PORT:-8080}
logLevel: ${LOG_LEVEL:-info}

persistConfig: true
persistIndex: true

stateStore:
  kind: redb
  path: ${DATA_DIR:-./data}/state.redb

defaultPriorityQueueCapacity: 50000
defaultDispatchBufferCapacity: 5000

sources:
  - kind: postgres
    id: orders-db
    autoStart: true
    host: ${DB_HOST}
    port: ${DB_PORT:-5432}
    database: ${DB_NAME}
    user: ${DB_USER}
    password: ${DB_PASSWORD}
    tables:
      - public.orders
      - public.customers
    bootstrapProvider:
      kind: postgres

queries:
  - id: pending-orders
    autoStart: true
    query: |
      MATCH (o:orders)
      WHERE o.status = 'pending'
      RETURN o.id, o.total, o.customer_id
    sources:
      - sourceId: orders-db

reactions:
  - kind: http
    id: webhook
    queries: [pending-orders]
    autoStart: true
    baseUrl: ${WEBHOOK_URL}
    token: ${WEBHOOK_TOKEN}
    routes:
      pending-orders:
        added:
          url: /orders/new
          method: POST

Top-level schema (overview)

# Server identity (also used as the default instance id in single-instance mode)
id: my-server

# Server HTTP API binding
host: 0.0.0.0
port: 8080

# Logging
logLevel: info

# Persist API changes back to the config file (if the file is writable)
persistConfig: true

# Single-instance mode instance settings (used when instances: [] is empty)
persistIndex: false
stateStore: null

defaultPriorityQueueCapacity: null
defaultDispatchBufferCapacity: null

# Component lists (structure documented on their dedicated pages)
sources: []
queries: []
reactions: []

# Multi-instance mode (when non-empty, the single-instance fields above are ignored)
instances: []

Server settings (always top-level)

These settings apply to the Drasi Server process itself.

Field	Type	Default	Description
`id`	string	Auto-generated UUID	Unique server identifier. In single-instance mode, this is also used as the DrasiLib instance id.
`host`	string	`0.0.0.0`	Bind address for the Drasi Server HTTP API. Must be a valid hostname or IP address.
`port`	integer	`8080`	HTTP API port (must be 1–65535).
`logLevel`	string	`info`	Log level: `trace`, `debug`, `info`, `warn`, `error`.
`persistConfig`	boolean	`true`	When `true` and the config file is writable, API changes are persisted back to the config file.

Notes

Read-only mode: If the config file is not writable, Drasi Server runs the API in read-only mode (regardless of persistConfig).
persistConfig: false means API changes are allowed but won’t be saved across restarts.

Instance settings (single-instance mode)

When instances is empty (the default), Drasi Server runs one DrasiLib instance, using the following top-level fields.

Field	Type	Default	Description
`persistIndex`	boolean	`false`	Enable persistent query indexing using RocksDB (stored under `./data/<instanceId>/index`).
`stateStore`	object	none	Optional state store for plugin runtime state persistence (see below).
`defaultPriorityQueueCapacity`	integer	none	If set, overrides the DrasiLib default priority queue capacity for queries/reactions.
`defaultDispatchBufferCapacity`	integer	none	If set, overrides the DrasiLib default dispatch buffer capacity for sources/queries.
`sources`	array	`[]`	Source plugin instances (see: Configure Sources).
`queries`	array	`[]`	Continuous queries.
`reactions`	array	`[]`	Reactions to query result change events (see: Configure Reactions).

State store configuration

The state store allows plugins (Sources, Bootstrap Providers, Reactions) to persist runtime state that survives restarts.

If stateStore is omitted, an in-memory state store is used and plugin state is lost on restart.

redb (file-based)

stateStore:
  kind: redb
  path: ./data/state.redb

Field	Type	Required	Description
`kind`	string	Yes	Must be `redb`.
`path`	string	Yes	Path to the REDB file. Supports env interpolation (e.g. `${STATE_STORE_PATH:-./data/state.redb}`).

Multi-instance mode (instances)

When instances is non-empty, Drasi Server runs one DrasiLib instance per entry and uses per-instance component lists and instance settings.

Important

When `instances` is set, the following **top-level** fields are ignored for runtime behavior: `persistIndex`, `stateStore`, `defaultPriorityQueueCapacity`, `defaultDispatchBufferCapacity`, `sources`, `queries`, `reactions`.

Instance fields

Field	Type	Default	Description
`id`	string	Auto-generated UUID	Unique instance id (used in API routes and for persistence paths).
`persistIndex`	boolean	`false`	Enable persistent indexing for this instance.
`stateStore`	object	none	Optional per-instance state store.
`defaultPriorityQueueCapacity`	integer	none	Optional per-instance default.
`defaultDispatchBufferCapacity`	integer	none	Optional per-instance default.
`sources`	array	`[]`	Sources for this instance.
`queries`	array	`[]`	Queries for this instance.
`reactions`	array	`[]`	Reactions for this instance.

Example

host: 0.0.0.0
port: 8080
logLevel: info
persistConfig: true

instances:
  - id: analytics
    persistIndex: true
    stateStore:
      kind: redb
      path: ./data/analytics.redb
    sources: []
    queries: []
    reactions: []

  - id: monitoring
    persistIndex: false
    sources: []
    queries: []
    reactions: []

Environment variable interpolation

Many scalar config values support POSIX-style interpolation:

Pattern	Behavior
`${VAR}`	Required. Loading fails if `VAR` is not set.
`${VAR:-default}`	Optional with default fallback.

Example:

host: ${SERVER_HOST:-0.0.0.0}
port: ${SERVER_PORT:-8080}
logLevel: ${DRASI_LOG_LEVEL:-info}
stateStore:
  kind: redb
  path: ${STATE_STORE_PATH:-./data/state.redb}

When running drasi-server, it will also attempt to load a .env file from the same directory as the config file.

Common Validation Errors

Error Message	Cause	Solution
`unknown field 'field_name'`	Using an unrecognized field name	Check spelling and use camelCase (e.g., `autoStart` not `auto_start`)
`missing field 'id'`	Required field not provided	Add the missing `id` field to the component
`invalid type: expected string`	Wrong data type	Check that the value type matches the schema (string, integer, boolean)
`Environment variable 'VAR' not set`	Required env var missing	Set the variable or use `${VAR:-default}` syntax
`invalid port: out of range`	Port number invalid	Use a port between 1 and 65535
`duplicate id`	Two components share the same id	Ensure all source, query, and reaction IDs are unique
`unknown source 'sourceId'`	Query references non-existent source	Check the `sourceId` in query sources matches a defined source
`source 'id' already subscribed by 'query'`	Source used by multiple queries	Each source can only be subscribed to by one query

Validating configuration

Use the CLI to validate a configuration file without starting the server:

drasi-server validate --config config/server.yaml

To print resolved server settings (host/port/log level) after env expansion:

drasi-server validate --config config/server.yaml --show-resolved

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Configuration Reference

Configuration Reference

Quick Reference

Key rules

File location

Minimal Configuration

Full Configuration Example

Top-level schema (overview)

Server settings (always top-level)

Notes

Instance settings (single-instance mode)

State store configuration

redb (file-based)

Multi-instance mode (instances)

Instance fields

Example

Environment variable interpolation

Common Validation Errors

Validating configuration

Feedback

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