mbtileserver

README

mbtileserver

A simple Go-based server for map tiles stored in mbtiles format.

It currently provides support for png, jpg, and pbf (vector tile) tilesets according to version 1.0 of the mbtiles specification. Tiles are served following the XYZ tile scheme, based on the Web Mercator coordinate reference system. UTF8 Grids are also supported.

In addition to tile-level access, it provides:

• TileJSON 2.1.0 endpoint for each tileset, with full metadata from the mbtiles file.
• a preview map for exploring each tileset.
• a minimal ArcGIS tile map service API (work in progress)

We have been able to host a bunch of tilesets on an AWS t2.nano virtual machine without any issues.

Goals

• Provide a web tile API for map tiles stored in mbtiles format
• Be fast
• Run on small resource cloud hosted machines (limited memory & CPU)
• Be easy to install and operate

Supported Go versions

Requires Go 1.10+. Go 1.13 is recommended for full support.

mbtileserver uses go modules and follows standard practices as of Go 1.13.

Due to varying degrees of go module support between Go versions 1.10 and 1.13, we provide a vendor directory with dependencies for older versions. This is deprecated and will be removed in an upcoming version.

Note: Go versions 1.11.0 - 1.11.3 are not supported, use Go 1.11.4. This is due to differences in how those versions handled go modules (see).

Installation

You can install this project with

go get github.com/consbio/mbtileserver

This will create and install an executable called mbtileserver.

Usage

From within the repository root ($GOPATH/bin needs to be in your $PATH):

$  mbtileserver --help
Serve tiles from mbtiles files.

Usage:
  mbtileserver [flags]

Flags:
  -c, --cert string       X.509 TLS certificate filename.  If present, will be used to enable SSL on the server.
  -d, --dir string        Directory containing mbtiles files. (default "./tilesets")
      --domain string     Domain name of this server.    NOTE: only used for AutoTLS.
      --dsn string        Sentry DSN
  -h, --help              help for mbtileserver
  -k, --key string        TLS private key
      --path string       URL root path of this server (if behind a proxy)
  -p, --port int          Server port. Default is 443 if --cert or --tls options are used, otherwise 8000. (default -1)
  -s, --secret-key string Shared secret key used for HMAC request authentication
  -t, --tls               Auto TLS using Let's Encrypt
  -r, --redirect          Redirect HTTP to HTTPS
      --enable-reload     Enable graceful reload
  -v, --verbose           Verbose logging

So hosting tiles is as easy as putting your mbtiles files in the tilesets directory and starting the server. Woo hoo!

You can have multiple directories in your tilesets directory; these will be converted into appropriate URLs:

<tile_dir>/foo/bar/baz.mbtiles will be available at /services/foo/bar/baz.

When you want to remove, modify, or add new tilesets, simply restart the server process or use the reloading process below.

If a valid Sentry DSN is provided, warnings, errors, fatal errors, and panics will be reported to Sentry.

If redirect option is provided, the server also listens on port 80 and redirects to port 443.

If the --tls option is provided, the Let's Encrypt Terms of Service are accepted automatically on your behalf. Please review them here. Certificates are cached in a .certs folder created where you are executing mbtileserver. Please make sure this folder can be written by the mbtileserver process or you will get errors. Certificates are not requested until the first request is made to the server. We recommend that you initialize these after startup by making a request against https://<hostname>/services and watching the logs from the server to make sure that certificates were processed correctly. Common errors include Let's Encrypt not being able to access your server at the domain you provided. localhost or internal-only domains will not work.

If either --cert or --tls are provided, the default port is 443.

You can also set up server config using environment variables instead of flags, which may be more helpful when deploying in a docker image. Use the associated flag to determine usage. The following variables are available:

• PORT (--port)
• TILE_DIR (--dir)
• PATH_PREFIX (--path)
• DOMAIN (--domain)
• TLS_CERT (--cert)
• TLS_PRIVATE_KEY (--key)
• AUTO_TLS (--tls)
• REDIRECT (--redirect)
• DSN (--dsn)
• VERBOSE (--verbose)
• HMAC_SECRET_KEY (--secret-key)

Example:

$ PORT=7777 TILE_DIR=./path/to/your/tiles VERBOSE=true mbtileserver

In a docker-compose.yml file it will look like:

mbtileserver:
  ...

  environment:
    PORT: 7777
    TILE_DIR: "./path/to/your/tiles"
    VERBOSE: true
  entrypoint: mbtileserver

  ...

Reload

mbtileserver optionally supports graceful reload (without interrupting any in-progress requests). This functionality must be enabled with the --enable-reload flag. When enabled, the server can be reloaded by sending it a HUP signal:

$ kill -HUP <pid>

Reloading the server will cause it to pick up changes to the tiles directory, adding new tilesets and removing any that are no longer present.

Using with a reverse proxy

You can use a reverse proxy in front of mbtileserver to intercept incoming requests, provide TLS, etc.

We have used both Caddy and NGINX for our production setups in various projects, usually when we need to proxy to additional backend services.

To make sure that the correct request URL is passed to mbtileserver so that TileJSON and map preview endpoints work correctly, make sure to have your reverse proxy send the following headers:

Scheme (HTTP vs HTTPS): one of X-Forwarded-Proto, X-Forwarded-Protocol, X-Url-Scheme to set the scheme of the request. OR X-Forwarded-Ssl to automatically set the scheme to HTTPS.

Host: Set Host and X-Forwarded-Host.

Caddy Example:

For mbtileserver running on port 8000 locally, add the following to the block for your domain name:

<domain_name> {
    proxy /services localhost:8000 {
        transparent
    }
}

Using transparent preset for the proxy settings instructs Caddy to automatically set appropriate headers.

NGINX Example:

For mbtileserver running on port 8000 locally, add the following to your server block:

server {
   <other config options>

    location /services {
        proxy_set_header Host $http_host;
        proxy_set_header X-Forwarded-Host $server_name;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_pass http://localhost:8000;
    }
}

Docker

Pull the latest image from Docker Hub:

docker pull consbio/mbtileserver:latest

To build the Docker image locally (named mbtileserver):

docker build -t mbtileserver -f Dockerfile .

To run the Docker container on port 8080 with your tilesets in <host tile dir>. Note that by default, mbtileserver runs on port 8000 in the container.

docker run --rm -p 8080:8000 -v <host tile dir>:/tilesets  consbio/mbtileserver

You can pass in additional command-line arguments to mbtileserver, for example, to use certificates and files in <host cert dir> so that you can access the server via HTTPS. The example below uses self-signed certificates generated using mkcert. This example uses automatic redirects, which causes mbtileserver to also listen on port 80 and automatically redirect to 443.

docker run  --rm -p 80:80 443:443 -v <host tile dir>:/tilesets -v <host cert dir>:/certs/ consbio/mbtileserver -c /certs/localhost.pem -k /certs/localhost-key.pem -p 443 --redirect

Alternately, use docker-compose to run:

docker-compose up -d

The default docker-compose.yml configures mbtileserver to connect to port 8080 on the host, and uses the ./mbtiles/testdata folder for tilesets. You can use your own docker-compose.override.yml or environment specific files to set these how you like.

To reload the server:

docker exec -it mbtileserver sh -c "kill -HUP 1"

Specifications

• expects mbtiles files to follow version 1.0 of the mbtiles specification. Version 1.1 is preferred.
• implements TileJSON 2.1.0

Creating Tiles

You can create mbtiles files using a variety of tools. We have created tiles for use with mbtileserver using:

• TileMill (image tiles)
• tippecanoe (vector tiles)
• pymbtiles (tiles created using Python)
• tpkutils (image tiles from ArcGIS tile packages)

The root name of each mbtiles file becomes the "tileset_id" as used below.

XYZ Tile API

The primary use of mbtileserver is as a host for XYZ tiles.

These are provided at: /services/<tileset_id>/tiles/{z}/{x}/{y}.<format>

where <format> is one of png, jpg, pbf depending on the type of data in the tileset.

If UTF-8 Grid data are present in the mbtiles file, they will be served up over the grid endpoint: http://localhost/services/states_outline/tiles/{z}/{x}/{y}.json

Grids are assumed to be gzip or zlib compressed in the mbtiles file. These grids are automatically spliced with any grid key/value data if such exists in the mbtiles file.

TileJSON API

mbtileserver automatically creates a TileJSON endpoint for each service at /services/<tileset_id>. The TileJSON uses the same scheme and domain name as is used for the incoming request; the --domain setting does not have an affect on auto-generated URLs.

This API provides most elements of the metadata table in the mbtiles file as well as others that are automatically inferred from tile data.

For example, http://localhost/services/states_outline

returns something like this:

{
  "bounds": [
    -179.23108,
    -14.601813,
    179.85968,
    71.441055
  ],
  "center": [
    0.314297,
    28.419622,
    1
  ],
  "credits": "US Census Bureau",
  "description": "States",
  "format": "png",
  "id": "states_outline",
  "legend": "[{\"elements\": [{\"label\": \"\", \"imageData\": \"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAUCAYAAACNiR0NAAAAAXNSR0IB2cksfwAAAAlwSFlzAAAOxAAADsQBlSsOGwAAAGFJREFUOI3tlDEOgEAIBClI5kF+w0fxwXvQdjZywcZEtDI31YaQgWrdPsYzAPFGJCmmEAhJGzCash0wSVE/HHnlKcDMfrPXYgmXcAl/JswK6lCrz89BdGVm1+qrH0bbWDgA3WwmgzD8ueEAAAAASUVORK5CYII=\"}], \"name\": \"tl_2015_us_state\"}]",
  "map": "http://localhost/services/states_outline/map",
  "maxzoom": 4,
  "minzoom": 0,
  "name": "states_outline",
  "scheme": "xyz",
  "tags": "states",
  "tilejson": "2.1.0",
  "tiles": [
    "http://localhost/services/states_outline/tiles/{z}/{x}/{y}.png"
  ],
  "type": "overlay",
  "version": "1.0.0"
}

Map preview

mbtileserver automatically creates a map preview page for each tileset at /services/<tileset_id>/map.

This currently uses Leaflet for image tiles and Mapbox GL JS for vector tiles.

ArcGIS API

This project currently provides a minimal ArcGIS tiled map service API for tiles stored in an mbtiles file. This should be sufficient for use with online platforms such as Data Basin. Because the ArcGIS API relies on a number of properties that are not commonly available within an mbtiles file, so certain aspects are stubbed out with minimal information.

This API is not intended for use with more full-featured ArcGIS applications such as ArcGIS Desktop.

Request authorization

Providing a secret key with -s/--secret-key or by setting the HMAC_SECRET_KEY environment variable will restrict access to all server endpoints and tile requests. Requests will only be served if they provide a cryptographic signature created using the same secret key. This allows, for example, an application server to provide authorized clients a short-lived token with which the clients can access tiles for a specific service.

Signatures expire 15 minutes from their creation date to prevent exposed or leaked signatures from being useful past a small time window.

Creating signatures

A signature is a URL-safe, base64 encoded HMAC hash using the SHA1 algorithm. The hash key is an SHA1 key created from a randomly generated salt, and the secret key string. The hash payload is a combination of the ISO-formatted date when the hash was created, and the authorized service id.

The following is an example signature, created in Go for the serivce id test, the date 2019-03-08T19:31:12.213831+00:00, the salt 0EvkK316T-sBLA, and the secret key YMIVXikJWAiiR3q-JMz1v2Mfmx3gTXJVNqme5kyaqrY

Create the SHA1 key:

serviceId := "test"
date := "2019-03-08T19:31:12.213831+00:00"
salt := "0EvkK316T-sBLA"
secretKey := "YMIVXikJWAiiR3q-JMz1v2Mfmx3gTXJVNqme5kyaqrY"

key := sha1.New()
key.Write([]byte(salt + secretKey))

Create the signature hash:

hash := hmac.New(sha1.New, key.Sum(nil))
message := fmt.Sprintf("%s:%s", date, serviceId)
hash.Write([]byte(message))

Finally, base64-encode the hash:

b64hash := base64.RawURLEncoding.EncodeToString(hash.Sum(nil))
fmt.Println(b64hash) // Should output: 2y8vHb9xK6RSxN8EXMeAEUiYtZk

Making request

Authenticated requests must include the ISO-fromatted date, and a salt-signature combination in the form of: <salt>:<signature>. These can be provided as query parameters:

?date=2019-03-08T19:31:12.213831%2B00:00&signature=0EvkK316T-sBLA:YMIVXikJWAiiR3q-JMz1v2Mfmx3gTXJVNqme5kyaqrY

Or they can be provided as request headers:

X-Signature-Date: 2019-03-08T19:31:12.213831+00:00
X-Signature: 0EvkK316T-sBLA:YMIVXikJWAiiR3q-JMz1v2Mfmx3gTXJVNqme5kyaqrY

Development

Dependencies are managed using go modules. Vendored dependencies are stored in vendor folder by using go mod vendor.

On Windows, it is necessary to install gcc in order to compile mattn/go-sqlite3. MinGW or TDM-GCC should work fine.

If you experience very slow builds each time, it may be that you need to first run

go build -a .

to make subsequent builds much faster.

Development of the templates and static assets likely requires using node and npm. Install these tools in the normal way.

From the handlers/templates/static folder, run

$npm install

to pull in the static dependencies. These are referenced in the package.json file.

Then to build the minified version, run:

$gulp build

Modifying the .go files always requires re-running go build ..

In case you have modified the templates and static assets, you need to run go generate ./handlers to ensure that your modifications are embedded into the executable. For this to work, you must have [github.com/shurcooL/vfsgen)[https://github.com/shurcooL/vfsgen) installed.

go generate ./handlers/handlers.go

This will rewrite the assets_vfsdata.go which you must commit along with your modification. You should run go build after go generate.

During the development cycle you may use go build -tags dev . to build the binary, in which case it will always take the assets from the relative file path handlers/templates/ directly and you can omit the go generate step. (note: this is currently not working properly) But do not forget to perform it in the end.

Changes

0.6.1

• upgraded Docker containers to Go 1.14

0.6

• fixed bug in map preview when bounds are not defined for a tileset (#84)
• updated Leaflet to 1.6.0 and Mapbox GL to 0.32.0 (larger upgrades contingent on #65)
• fixed issues with --tls option (#89)
• added example proxy configuration for Caddy and NGINX (#91)
• fixed issues with map preview page using HTTP basemaps (#90)
• resolved template loading issues (#85)
• breaking changes:
  • handlers.go:
    • Removed TemplatesFromAssets as it was not used internally, and unlikely used externally
    • Removed secretKey from NewFromBaseDir parameters; this is replaced by calling SetRequestAuthKey on a ServiceSet.

0.5.0

• Added Docker support (#74, #75)
• Fix case-sensitive mbtiles URLs (#77)
• Add support for graceful reloading (#69, #72, #73)
• Add support for environment args (#70)
• All changes prior to 6/1/2019

Contributors ✨

Thanks goes to these wonderful people (emoji key):

Brendan Ward 💻 📖 🐛 📝 👀 🤔	Fabian Wickborn 💻 📖 🐛 🤔	Nik Molnar 💻 🤔 🐛	Nikolay Korotkiy 💻 🐛	Robert Brown 💻	Mihail 💻	Marko Burjek 💻
Kristjan 💻	evbarnett 🐛	walkaholic.me 🐛	Brian Voelker 🐛	Georg Leciejewski 🐛

This project follows the all-contributors specification. Contributions of any kind welcome!