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.

``Dockerfile
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.

$3

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 " ").

Configuration file

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

`bash
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.

$3

Configuration files can be written in multiple formats:

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

$3

YAML (config.yaml):

`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):

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

JavaScript (config.mjs):

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

$3

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.

`yaml


base.yaml


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

`yaml


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)

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| 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:

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

Or clone and run the repo:

`bash
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

`console
$ versatiles-google-cloud
Usage: versatiles-google-cloud [options] [bucket-name]

Initialises a server to serve files from a specified Google Bucket to a Google
Load Balancer with CDN, handles HTTP headers and compression, and provides a
RESTful API for VersaTiles containers.
For more details, visit:
https://github.com/versatiles-org/node-versatiles-google-cloud/

Arguments:
bucket-name Name of the Google Cloud Storage bucket.

Options:
-b, --base-url Set the public base URL. Defaults to
"http://localhost:/".
-c, --config Load configuration from a YAML file. CLI
arguments override config file values.
-d, --directory Set the bucket directory (prefix), e.g.,
"/public/".
-f, --fast-recompression Enable faster server responses by avoiding
recompression.
-l, --local-directory Ignore bucket and use a local directory
instead. Useful for local development and
testing.
-p, --port Set the server port. Default: 8080
-r, --rewrite-rule Set a rewrite rule. Must start with a "/".
E.g. "/tiles/osm/ /folder/osm.versatiles?"
(default: [])
-v, --verbose Enable verbose mode for detailed operational
logs.
-h, --help display help for command
`

Dependency Graph

`mermaid
---
config:
layout: elk
---
flowchart TB

subgraph 0["src"]
1["index.ts"]
subgraph 2["lib"]
3["config.ts"]
4["server.ts"]
subgraph 5["bucket"]
6["index.ts"]
7["bucket_google.ts"]
8["abstract.ts"]
B["metadata.ts"]
C["bucket_local.ts"]
end
9["recompress.ts"]
A["encoding.ts"]
D["responder.ts"]
E["response_headers.ts"]
F["rewrite.ts"]
subgraph G["versatiles"]
H["index.ts"]
I["cache.ts"]
J["versatiles.ts"]
end
end
end
1-->3
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

class 0,2,5,G subgraphs;
classDef subgraphs fill-opacity:0.1, fill:#888, color:#888, stroke:#888;
``

License

Unlicense