database

package database

import "github.com/vivint/rothko/database"

package database provides interfaces to storage of records.

Usage

type DB

type DB interface {
	Source
	Sink

	// Run will be called so that the DB can do asynchronous tasks. The
	// context will be canceled when it is expected to shut down.
	Run(ctx context.Context) error
}

DB represents a Source and a Sink.

type ResultCallback

type ResultCallback func(ctx context.Context, start, end int64, data []byte) (
	bool, error)

ResultCallback is a function used to pass results back from Query. The data slice must not be modified, and no references must be kept after the function returns. Return if you will continue iterating.

type Sink

type Sink interface {
	// Queue adds the data for the metric and the given start and end times. If
	// the start time is before the last end time for the metric, no write is
	// guaranteed to happen. The data is not required to be persisted to disk
	// after the call returns, and may be flushed asynchronously. If the cb
	// parameter is not nil, it will be called when the data has been handled.
	// Written indicates if the data was written to disk, and err is not nil
	// if there were errors.
	Queue(ctx context.Context, metric string, start, end int64,
		data []byte, cb func(written bool, err error)) (err error)
}

Sink represents something that can add data about metrics.

type Source

type Source interface {
	// Query calls the ResultCallback with all of the data slices that end
	// strictly before the provided end time in strictly decreasing order by
	// their end. It will continue to call the ResultCallback until it exhausts
	// all of the records, or the callback returns false.
	Query(ctx context.Context, metric string, end int64, buf []byte,
		cb ResultCallback) error

	// QueryLatest returns the latest value stored for the metric. buf is used
	// as storage for the data slice if possible.
	QueryLatest(ctx context.Context, metric string, buf []byte) (
		start, end int64, data []byte, err error)

	// Metrics calls the callback once for every metric stored.
	Metrics(ctx context.Context, cb func(name string) (bool, error)) error
}

Source can be used to read data about metrics.