Tegola
Tegola is a vector tile server delivering Mapbox Vector Tiles leveraging PostGIS as the data provider.
Features
- Native geometry processing (simplification, clipping, make valid, intersection, contains, scaling, translation)
- Mapbox Vector Tile v2 specification compliant.
- Embedded viewer with auto generated style for quick data visualization and inspection.
- Support for PostGIS and GeoPackage data providers. Extensible design to support additional data providers.
- Support for several cache backends: file, s3, redis, azure blob store.
- Cache seeding and invalidation via individual tiles (ZXY), lat / lon bounds and ZXY tile list.
- Parallelized tile serving and geometry processing.
- Support for Web Mercator (3857) and WGS84 (4326) projections.
- Support for AWS Lambda.
Usage
tegola is a vector tile server
Version: v0.7.0
Usage:
tegola [command]
Available Commands:
cache Manipulate the tile cache
help Help about any command
serve Use tegola as a tile server
version Print the version number of tegola
Flags:
--config string path to config file (default "config.toml")
-h, --help help for tegola
Use "tegola [command] --help" for more information about a command.
Running tegola as a vector tile server
- Download the appropriate binary of tegola for your platform via the release page.
- Setup your config file and run. Dy default tegola looks for a
config.toml
in the same directory as the binary. You can set a different location for theconfig.toml
using a command flag:
./tegola serve --config=/path/to/config.toml
Server Endpoints
/
The server root will display a built in viewer with an auto generated style. For example:
/maps/:map_name/:z/:x/:y
Return vector tiles for a map. The URI supports the following variables:
:map_name
is the name of the map as defined in theconfig.toml
file.:z
is the zoom level of the map.:x
is the row of the tile at the zoom level.:y
is the column of the tile at the zoom level.
/maps/:map_name/:layer_name/:z/:x/:y
Return vector tiles for a map layer. The URI supports the same variables as the map URI with the additional variable:
:layer_name
is the name of the map layer as defined in theconfig.toml
file.
/capabilities
Return a JSON encoded list of the server's configured maps and layers with various attributes.
/capabilities/:map_name
Return TileJSON details about the map.
/maps/:map_name/style.json
Return an auto generated Mapbox GL Style for the configured map.
Configuration
The tegola config file uses the TOML format. The following example shows how to configure a PostGIS data provider with two layers. The first layer includes a tablename
, geometry_field
and an id_field
. The second layer uses a custom sql
statement instead of the tablename
property.
Under the maps
section, map layers are associated with data provider layers and their min_zoom
and max_zoom
values are defined. Optionally, default_tags
can be setup which will be encoded into the layer. If the same tags are returned from a data provider, the data provider's values will take precedence.
[webserver]
port = ":9090" # port to bind the web server to. defaults ":8080"
[cache] # configure a tile cache
type = "file" # a file cache will cache to the local file system
basepath = "/tmp/tegola" # where to write the file cache
# register data providers
[[providers]]
name = "test_postgis" # provider name is referenced from map layers (required)
type = "postgis" # the type of data provider. currently only supports postgis (required)
host = "localhost" # postgis database host (required)
port = 5432 # postgis database port (required)
database = "tegola" # postgis database name (required)
user = "tegola" # postgis database user (required)
password = "" # postgis database password (required)
srid = 3857 # The default srid for this provider. Defaults to WebMercator (3857) (optional)
max_connections = 50 # The max connections to maintain in the connection pool. Default is 100. (optional)
ssl_mode = "prefer" # PostgreSQL SSL mode*. Default is "disable". (optional)
[[providers.layers]]
name = "landuse" # will be encoded as the layer name in the tile
tablename = "gis.zoning_base_3857" # sql or table_name are required
geometry_fieldname = "geom" # geom field. default is geom
id_fieldname = "gid" # geom id field. default is gid
srid = 4326 # the srid of table's geo data. Defaults to WebMercator (3857)
[[providers.layers]]
name = "roads" # will be encoded as the layer name in the tile
tablename = "gis.zoning_base_3857" # sql or table_name are required
geometry_fieldname = "geom" # geom field. default is geom
geometry_type = "linestring" # geometry type. if not set, tables are inspected at startup to try and infer the gemetry type
id_fieldname = "gid" # geom id field. default is gid
fields = [ "class", "name" ] # Additional fields to include in the select statement.
[[providers.layers]]
name = "rivers" # will be encoded as the layer name in the tile
geometry_fieldname = "geom" # geom field. default is geom
id_fieldname = "gid" # geom id field. default is gid
# Custom sql to be used for this layer. Note: that the geometery field is wraped
# in a ST_AsBinary() and the use of the !BBOX! token
sql = "SELECT gid, ST_AsBinary(geom) AS geom FROM gis.rivers WHERE geom && !BBOX!"
# maps are made up of layers
[[maps]]
name = "zoning" # used in the URL to reference this map (/maps/:map_name)
[[maps.layers]]
name = "landuse" # name is optional. If it's not defined the name of the ProviderLayer will be used.
# It can also be used to group multiple ProviderLayers under the same namespace.
provider_layer = "test_postgis.landuse" # must match a data provider layer
min_zoom = 12 # minimum zoom level to include this layer
max_zoom = 16 # maximum zoom level to include this layer
[maps.layers.default_tags] # table of default tags to encode in the tile. SQL statements will override
class = "park"
[[maps.layers]]
name = "rivers" # name is optional. If it's not defined the name of the ProviderLayer will be used.
# It can also be used to group multiple ProviderLayers under the same namespace.
provider_layer = "test_postgis.rivers" # must match a data provider layer
dont_simplify = true # optionally, turn off simplification for this layer. Default is false.
min_zoom = 10 # minimum zoom level to include this layer
max_zoom = 18 # maximum zoom level to include this layer
* more on PostgreSQL SSL mode here. The postgis
config also supports "ssl_cert" and "ssl_key" options are required, corresponding semantically with "PGSSLKEY" and "PGSSLCERT". These options do not check for environment variables automatically. See the section below on injecting environment variables into the config.
Supported PostGIS SQL tokens
The following tokens are supported in custom SQL queries for the PostGIS data provider:
!BBOX!
- [required] Will convert the z/x/y values into a bounding box to query the feature table with.!ZOOM!
- [optional] Pass in the zoom value for the request. Useful for filtering feature results by zoom.
Environment Variables
Config TOML
Environment variables can be injected into the configuration file. One caveat is that the injection has to be within a string, though the value it represents does not have to be a string.
The above config example could be written as:
# register data providers
[[providers]]
name = "test_postgis"
type = "postgis"
host = "${POSTGIS_HOST}" # postgis database host (required)
port = "${POSTGIS_PORT}" # recall this value must be an int
database = "${POSTGIS_DB}"
user = "tegola"
password = ""
srid = 3857
max_connections = "${POSTGIS_MAX_CONN}"
SQL Debugging
The following environment variables can be used for debugging:
TEGOLA_SQL_DEBUG
specify the type of SQL debug information to output. Currently support two values:
LAYER_SQL
: print layer SQL as they are parsed from the config file.EXECUTE_SQL
: print SQL that is executed for each tile request and the number of items it returns or an error.
Usage
$ TEGOLA_SQL_DEBUG=LAYER_SQL tegola serve --config=/path/to/conf.toml
The following environment variables can be used to control various runtime options:
TEGOLA_OPTIONS
specify a set of options comma or space delimited. Supports the following options
DontSimplifyGeo
to turn off simplification for all layers.SimplifyMaxZoom={{int}}
to set the max zoom that simplification will apply to. (14 is default)
Client side debugging
When debugging client side, it's often helpful to to see an outline of a tile along with it's Z/X/Y values. To encode a debug layer into every tile add the query string variable debug=true
to the URL template being used to request tiles. For example:
http://localhost:8080/maps/mymap/{z}/{x}/{y}.vector.pbf?debug=true
The requested tile will be encode a layer with the name
value set to debug
and include two features:
debug_outline
: a line feature that traces the border of the tiledebug_text
: a point feature in the middle of the tile with the following tags:zxy
: a string with theZ
,X
andY
values formatted as:Z:0, X:0, Y:0
Building from source
Tegola is written in Go and requires Go 1.8+ to compile from source. To build tegola from source, make sure you have Go installed and have cloned the repository to your $GOPATH
. Navigate to the repository then run the following commands:
cd cmd/tegola/
go build
You will now have a binary named tegola
in the current directory which is ready for running.
Build Flags The following build flags can be used to turn off certain features of tegola:
noAzblobCache
- turn off the Azure Blob cache back end.noS3Cache
- turn off the AWS S3 cache back end.noRedisCache
- turn off the Redis cache back end.noPostgisProvider
- turn off the PostGIS data provider.noGpkgProvider
- turn off the GeoPackage data provider. Note, GeoPackage uses CGO and will be turned off if the environment variableCGO_ENABLED=0
is set prior to building.noViewer
- turn off the built in viewer.pprof
- enable Go profiler. Start profile server by setting the environmentTEGOLA_HTTP_PPROF_BIND
environment (e.g.TEGOLA_HTTP_PPROF_BIND=localhost:6060
).
Example of using the build flags to turn of the Redis cache back end, the GeoPackage provider and the built in viewer.
go build -tags 'noRedisCache noGpkgProvider noViewer'
Turning off CGO Tegola uses CGO for certain functionality (i.e. GeoPackge support). To build tegola without CGO use the following command:
CGO_ENABLED=0 go build
License
See license file in repo.