aarondb - v4.2.0

aarondb/federation

Local, in-runtime federation over independently owned AaronDB databases.

This module deliberately composes local database actors only. It does not provide remote transport, coordinated writes, failover, quorum, or HA.

Types

FederatedResult 

pub type FederatedResult {
  FederatedResult(
    rows: List(FederatedRow),
    sources: List(String),
  )
}

Constructors 

  • FederatedResult(rows: List(FederatedRow), sources: List(String))

FederatedRow 

pub type FederatedRow {
  FederatedRow(
    source: String,
    row: dict.Dict(String, fact.Value),
  )
}

Constructors

Federation 

pub type Federation {
  Federation(sources: List(Source))
}

Constructors 

  • Federation(sources: List(Source))

FederationError 

pub type FederationError {
  SourceUnavailable(name: String)
  SourceTimeout(name: String)
}

Constructors 

  • SourceUnavailable(name: String)
  • SourceTimeout(name: String)

Source 

pub type Source {
  Source(name: String, db: process.Subject(transactor.Message))
}

Constructors

Values

new 

pub fn new(sources: List(Source)) -> Result(Federation, String)

Construct a local federation.

Source names must be non-empty and unique. Every source must expose the same set of declared schema attributes. This is a compatibility guard, not schema negotiation: callers own schema rollout across their databases.

query 

pub fn query(
  federation: Federation,
  query: ast.Query,
) -> Result(FederatedResult, FederationError)

Run a query using the default five-second source deadline.

See query_with_timeout for the fail-fast failure contract.

query_with_timeout 

pub fn query_with_timeout(
  federation: Federation,
  query: ast.Query,
  timeout_ms: Int,
) -> Result(FederatedResult, FederationError)

Run a query against every live source in stable source-name order.

This is the fail-fast federation API. It returns no result if any source is unavailable or fails to reply before timeout_ms; callers therefore cannot accidentally treat partial source successes as a complete federated read.

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