A location-aware user database implemented using Google S2 Geometry and Hashicorp's go-memdb (store setup)

store.go

package store

import (
	"github.com/golang/geo/s1"
	"github.com/golang/geo/s2"
	"github.com/hashicorp/go-memdb"
)

const (
	minLevel = 15
	maxLevel = 20
)

// Store contains the actual database and a search method.
type Store struct {
	db      *memdb.MemDB
	coverer *s2.RegionCoverer
}

// User object represents a user in the database.
type User struct {
	ID int
	// CellIDs of users should be leafs in the S2 hierarchy (level 30)
	CellID string
}

// New creates a new memDB store.
func New() (*Store, error) {
	s := Store{}
	err := s.initTable()

	if err != nil {
		return nil, err
	}
	s.coverer = &s2.RegionCoverer{
		MinLevel: minLevel,
		MaxLevel: maxLevel,
		MaxCells: 50,
	}

	return &s, nil
}

func (s *Store) initTable() error {
	schema := &memdb.DBSchema{
		Tables: map[string]*memdb.TableSchema{
			"users": {
				Name: "users",
				Indexes: map[string]*memdb.IndexSchema{
					"cellID": {
						Name:         "cellID",
						Unique:       false,
						AllowMissing: false,
						Indexer:      &memdb.StringFieldIndex{Field: "CellID"},
					},
				},
			},
		},
	}

	var err error
	s.db, err = memdb.NewMemDB(schema)
	if err != nil {
		return err
	}

	return nil
}