Configuration #

WebP Server Go can be configured by the following ways:

config.json file
Environment variables

Priority: Environment variables > config.json file.

Full configuration #

This is the full configuration with default values of WebP Server Go(except the IMG_MAP part), you can copy it to config.json and modify it to your needs, or if you just want to change some of the values, you can use environment variables to override the specific values.

You can use environment variables to override the configuration in config.json, the environment variables are added by using prefix WEBP_ and uppercase the field name, for example, HOST will be WEBP_HOST, IMG_PATH will be WEBP_IMG_PATH.

WEBP_ALLOWED_TYPES are separated by ,, for example, WEBP_ALLOWED_TYPES=jpg,png,webp. WEBP_CONVERT_TYPES are separated by ,, for example, WEBP_CONVERT_TYPES=webp,avif,jxl.

{
  "HOST": "0.0.0.0",
  "PORT": "3333",
  "QUALITY": "80",
  "IMG_PATH": "./pics",
  "EXHAUST_PATH": "./exhaust",
  "IMG_MAP": {},
  "ALLOWED_TYPES": ["jpg", "png", "jpeg", "bmp", "gif", "svg", "heic", "nef", "webp"],
  "CONVERT_TYPES": ["webp"],
  "STRIP_METADATA": true,
  "ENABLE_EXTRA_PARAMS": false,
  "EXTRA_PARAMS_CROP_INTERESTING": "InterestingAttention",
  "READ_BUFFER_SIZE": 4096,
  "CONCURRENCY": 262144,
  "DISABLE_KEEPALIVE": false,
  "CACHE_TTL": 259200
}

The IMG_MAP example as below:

"IMG_MAP": {
  "/2": "./pics2",
  "/3": "./pics3",
  "http://www.example.com": "https://docs.webp.sh"
}

Description of each field:

Field	Environment variables	Type	Description
`HOST`	`WEBP_HOST`	string	Host to listen on
`PORT`	`WEBP_PORT`	string	Port to listen on
`QUALITY`	`WEBP_QUALITY`	string	Quality of image, from 0 to 100, 100 means lossless conversion.
`IMG_PATH`	`WEBP_IMG_PATH`	string	Path to the image directory(of original images), if you’d like to use a remote backend(such as external Nginx served static site, Aliyun OSS or Tencent COS), please refer to Remote Backend.
`EXHAUST_PATH`	`WEBP_EXHAUST_PATH`	string	Path to the cache directory(of WebP images), for example, with `EXHAUST_PATH` set to `/var/cache/webp`, your `webp` image will be saved at `/var/cache/webp/pics/tsuki.jpg.1582558990.webp`.
`IMG_MAP`	/	dict	Map of URI/Host to image, if this is present then `IMG_PATH` and `EXHAUST_PATH` will be ignored, see more on MultiPath page
`ALLOWED_TYPES`	`WEBP_ALLOWED_TYPES`	list	List of allowed image types
`CONVERT_TYPES`	`WEBP_CONVERT_TYPES`	string	The image types list that WebP Server will try to convert to, default is `["webp"]` which means it will only try to convert image to WebP, available options: `["webp","avif","jxl"]`.
`STRIP_METADATA`	`WEBP_STRIP_METADATA`	bool	Whether to Strip EXIF metadata from images.
`ENABLE_EXTRA_PARAMS`	`WEBP_ENABLE_EXTRA_PARAMS`	bool	Means whether to enable Extra Parameters, basically it allows you to do some transform on images like `https://img.webp.sh/path/tsuki.jpg?width=20`, you can find more info on Extra Parameters page.
`EXTRA_PARAMS_CROP_INTERESTING`	`WEBP_EXTRA_PARAMS_CROP_INTERESTING`	string	Defines how should WebP Server crop image when `ENABLE_EXTRA_PARAMS` is on and image requests contains both `width` and `height`, available options are: “InterestingNone”, “InterestingEntropy”, “InterestingCentre”, “InterestingAttention”, “InterestringLow”, “InterestingHigh”, “InterestingAll”, you can find more info on Extra Parameters page.
`READ_BUFFER_SIZE`	`WEBP_READ_BUFFER_SIZE`	number	per-connection buffer size for requests’ reading. This also limits the maximum header size. Increase this buffer if your clients send multi-KB RequestURIs and/or multi-KB headers (for example, BIG cookies).
`CONCURRENCY`	`WEBP_CONCURRENCY`	number	Maximum number of concurrent connections
`DISABLE_KEEPALIVE`	`WEBP_DISABLE_KEEPALIVE`	string	Disable keep-alive connections, the server will close incoming connections after sending the first response to the client
`CACHE_TTL`	`WEBP_CACHE_TTL`	number	Cache TTL(minutes) for Remote Backends(Proxy Mode), we use `HEAD` request to get remote image info, so your backend needs to support `HEAD` request, after first successfuly `HEAD` request, it will be cached for `CACHE_TTL` minutes, during that period, we will not send `HEAD` request again and use local cache for rendering. Setting this value to 0 means cache forever.

Configuration example #

Suppose your website and image has the following pattern:

Image Path	Website Path
`/var/www/img.webp.sh/path/tsuki.jpg`	`https://img.webp.sh/path/tsuki.jpg`

And you wish to enable Extra Parameters, then

./pics should be changed to /var/www/img.webp.sh
./exhaust is cache folder for output images, by default it will be in exhaust directory alongside with docker-compose.yml file, if you’d like to keep cached images in another folder as , you can change ./exhaust to /some/other/path/to/exhaust
ENABLE_EXTRA_PARAMS can be passed in by environment variable WEBP_ENABLE_EXTRA_PARAMS=true

Your docker-compose.yml file can be written as follows:

version: '3'

services:
  webp:
    image: webpsh/webp-server-go
    restart: always
    environment:
      - WEBP_ENABLE_EXTRA_PARAMS=true
    volumes:
      - /var/www/img.webp.sh:/opt/pics
      - ./exhaust:/opt/exhaust
      - ./metadata:/opt/metadata
    ports:
      - 127.0.0.1:3333:3333