VersaTiles Server for Google Cloud Run

This tool solves perfectly the use cases, when you want to publish multiple map application using multiple versatiles tile sources in Google Cloud. E.g. for data journalists, academia, ...

[!WARNING] It is strongly recommended:

• always use a CDN in front of this server and
• not to modify/overwrite existing files in the bucket, as this could result in corrupted data being delivered!

Outline:

1. Store static files (*.html, *.js, *.css, …) and map tiles (*.versatiles) in a Google Storage Bucket.
2. Run this Node.js server in Google Cloud Run using Bucket name/path as argument
3. Put a Loadbalancer (with DNS and CDN) in front of the Google Cloud Run service.

• Now you can serve the files in the Bucket publicly.
• This server will make sure that every file will be compressed optimally according to "accept-encoding" header of the browser.
• *.versatiles files will not be served. Instead the server will provide a simple GET API to access every tile, and serve them with optimal compression. E.g. tile x=4, y=5, z=6 in file gs://bucket/map/earth.versatiles could be accessed via https://public.domain.com/map/earth.versatiles?tiles/6/4/5

Run in Google Cloud Run

Run the following Docker Container in Google Cloud Run, e.g. by using Google Cloud Build.

FROM node:20-alpine
RUN npm install -g @versatiles/google-cloud
EXPOSE 8080
CMD npx versatiles-google-cloud -b "$BASE_URL" "$BUCKET_NAME"

Path rewriting

You can define path rewriting rules to map public URLs to different paths in the bucket. Use the -r or --rewrite-rule option to specify rules in the format /public/path /bucket/path.

Rules can use custom pattern matching by utilizing Custom Matching Parameters. For example, the rule /tiles/:source.versatiles /data/:source.versatiles will rewrite requests like /tiles/osm.versatiles to /data/osm.versatiles.

Complex matching

You can create more complex matching patterns using regular expressions. For instance, the rule /apps:any((?!.*\.[^/]+$).*)? /apps:any((?!.*\.[^/]+$).*)?/index.html will match any path under /apps that does not end with a file extension and rewrite it to serve the corresponding index.html file.

[!NOTE] When using regular expressions in rewrite rules, ensure that white-space-matches are defined using thier specific form (\s) since standard white spaces ( ) are used to separate source and destination (-r "<source> <destination>").

Configuration file

Instead of passing all options via command line arguments, you can use a configuration file with the -c or --config option:

versatiles-google-cloud --config ./config.yaml

CLI arguments always override values from the configuration file. This allows you to define defaults in the config file and override specific values as needed.

Supported formats

Configuration files can be written in multiple formats:

• YAML (.yaml, .yml)
• JSON (.json)
• JavaScript (.js, .mjs, .cjs)
• TypeScript (.ts, .mts, .cts)

Example configuration file

YAML (config.yaml):

bucket: "my-tiles-bucket"
baseUrl: "https://tiles.example.com/"
directory: "/public/"
port: 8080
fastRecompression: false
verbose: false

rewriteRules:
  "/tiles/:name": "/geodata/:name.versatiles"
  "/apps:any((?!.*\\.[^/]+$).*)?": "/apps:any/index.html"

JSON (config.json):

{
  "bucket": "my-tiles-bucket",
  "baseUrl": "https://tiles.example.com/",
  "port": 8080,
  "rewriteRules": {
    "/tiles/:name": "/geodata/:name.versatiles"
  }
}

JavaScript (config.mjs):

export default {
  bucket: "my-tiles-bucket",
  baseUrl: "https://tiles.example.com/",
  port: 8080,
};

Configuration inheritance

Configuration files can extend other configurations using the extends property. This allows you to create a base configuration and override specific values in derived configurations.

# base.yaml
bucket: "production-bucket"
port: 8080
verbose: false
rewriteRules:
  "/tiles/:name": "/geodata/:name.versatiles"

# development.yaml
extends: ./base.yaml
bucket: "dev-bucket"
verbose: true

When using extends:

• All values from the parent config are inherited
• Values in the child config override parent values
• For rewriteRules, child rules are merged with parent rules (child rules take precedence)
• Multi-level inheritance is supported (grandparent → parent → child)

Configuration options

| Option | Type | Description | | ------------------- | ------- | -------------------------------------------- | | bucket | string | Name of the Google Cloud Storage bucket | | baseUrl | string | Public base URL | | directory | string | Bucket directory prefix | | port | integer | Server port (default: 8080) | | fastRecompression | boolean | Enable fast recompression mode | | localDirectory | string | Use local directory instead of bucket | | verbose | boolean | Enable verbose logging | | rewriteRules | object | Object mapping source paths to target paths | | extends | string | Path to parent configuration file to inherit |

[!NOTE] When using --config, the bucket name can be omitted from the command line if it's specified in the config file. The bucket is only required if localDirectory is not set.

Test locally

Install @versatiles/google-cloud globally and run:

npm install -g @versatiles/google-cloud
versatiles-google-cloud -f -l local/data/

Or clone and run the repo:

git clone https://github.com/versatiles-org/node-versatiles-google-cloud.git
cd node-versatiles-google-cloud
npm install
npm start -f -l local/data/

The arguments used:

• -f or --fast-recompression disables recompression, so it's faster if you're developing locally.
• -l or --local-directory uses a local directory instead of a Google Bucket.

Note that for security and performance reasons no file listing is implemented. If you have a file such as local/data/app/index.html you will need to open the correct URL in your browser to view the file: http://localhost:8080/app/index.html

Options

1-->4 4-->6 4-->D 4-->F 4-->H 6-->7 6-->C 7-->8 7-->B 8-->9 9-->A C-->8 C-->B D-->A D-->9 D-->E E-->A H-->I I-->J

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## License

[Unlicense](./LICENSE.md)