Documentation
¶
Overview ¶
geolocate exposes a function to obtain geographical coordinates for a given country. Previously, we used a City location database to obtain a country assignment for the request IP. This new approach moves in the direction of delegating the "country" or region geolocation to the client side (and let it override when needed), which greatly simplifies the responsibility of keeping a geodb up to date. The clients are also expected to pass a country code for background queries.
auto-generated code. Do NOT edit.
auto-generated code. Do NOT edit.
Index ¶
- Constants
- Variables
- func ContinentCodeToLabel(i int) string
- func ContinentNameToInt(s string) int
- func CountryCodes() []string
- func Distance(from, to *Point) float64
- func DistanceBetweenCountries(cc string, to string) (float64, error)
- func DistanceFromCountry(cc string, to *Point) (float64, error)
- func GeolocateCities(target []string) map[string]Point
- func GetContinentForCountryCode(cc string) int
- func GetEstimatedLatencyBetweenCountries(lm *latency.Metric, from, to string) float64
- func GetNearestCountry(from string, countryCodes []string) (string, error)
- func GetRegionForCountryCode(cc string) int
- func IsValidCountryCode(cc string) bool
- func PickBestLocations(lm *latency.Metric, cc string, locations []*models.Location) []*models.Location
- func RegionFromLabel(s string) int
- func RegionToLabel(i int) string
- func SortLocationsByDistanceToCountry(cc string, locations []*models.Location) []*models.Location
- func SortLocationsByEstimatedLatencyToCountry(lm *latency.Metric, cc string, locations []*models.Location) []*models.Location
- type Country
- type Point
Constants ¶
const ( XX = iota // unknown AN // antarctica AS // asia AF // africa EU // europe NA // north america SA // south america OC // oceania )
const ( UnknownRegion = iota North South )
Variables ¶
var ErrUnknownCountry = "unknown country code"
Functions ¶
func ContinentCodeToLabel ¶
func ContinentNameToInt ¶
func CountryCodes ¶
func CountryCodes() []string
func DistanceBetweenCountries ¶
DistanceBetweenCountries expects two country codes, and it will return the great circle distance (in km) between the centroids for the two countries.
func DistanceFromCountry ¶
DistanceFromCountry returns the great circle distance between a target `Point` and a country (specified by country code).
func GeolocateCities ¶
GeolocateCities receives an array of strings, and it returns a map[string]Point
func GetEstimatedLatencyBetweenCountries ¶
GetEstimatedLatencyBetweenCountries will return an estimation of latency (in ms) derived from an empirical dataset. This can be used to correct naive distance calculations, and sort locations accordingly.
func GetNearestCountry ¶
GetNearestCountry receives an array of country codes, and returns the one that is nearest.
func GetRegionForCountryCode ¶
func IsValidCountryCode ¶
func PickBestLocations ¶
func PickBestLocations(lm *latency.Metric, cc string, locations []*models.Location) []*models.Location
PickBestLocations calls the two methods (distance, latency) and merges the results. Note: this method picks the union of the two calls, so it might actually return more than `maxLocations`. TODO: this method is a workaround to the fact that the latency calculation is very blurry since it takes the average of the whole country. TODO: this is a good place to add region preferences.
func RegionFromLabel ¶
func RegionToLabel ¶
func SortLocationsByDistanceToCountry ¶
SortLocationsByDistanceToCountry return an array of locations sorted by "great circle distance" to the centroid of a given country. This is a very naive approach, but it's probably good enough for a small number of hand-picked locations like the Riseup provider uses right now.
You might also be interested in using SortLocationsByEstimatedLatency (see below), which uses an empirical model of a latency metric.
For the sake of fairness, and for providers with limited resources in terms of adding different locations, we might assign gateways to specific regions. The region and continent fields might be useful for these lookups.
func SortLocationsByEstimatedLatencyToCountry ¶
func SortLocationsByEstimatedLatencyToCountry( lm *latency.Metric, cc string, locations []*models.Location) []*models.Location
TODO: work in progress. This is correctly sorting locations by latency to the AVERAGE latency to the country in which the location is in, but we might need to desaggregate the database. Problem is that we need the equivalent of cloud regions: sort by proximity to US-west, AS-east etc.
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