goggler

Website screenshot microservice written in Golang that caches screenshots on disk or S3 storage

Compiling and Running

Compile and run with:

go build github.com/mkalus/goggler/cmd/goggler && GOGGLER_DEBUG=1 ./goggler

Point your Browser to the URL: http://localhost:8080/?url=https%3A%2F%2Fduckduckgo.com%2F&wait=2000

Note: Goggler uses ChromeDP and needs Chrome or Chromium to work. This means it has to be able to access and start Chrome or Chromium somehow (Chrome in path variable or the like).

Parameters

Valid URI parameters:

• url URL to take screenshot from (required)
• width Width of image and viewport (might be scaled up or down, see below, default: 1920)
• height Height of image and viewport (might be scaled up or down, see below, default: 1024)
• scale Scale of image and viewport (final width and height are multiplied by this, default: 0.2)
• quality PNG image quality (default: 90)
• wait Time in ms to wait until screenshot is taken (to wait for rendering to finish, default: 2000 = 2 secs)
• timeout Timeout in ms after which request is cancelled (default: 60000 = 60 secs)
• maxage Maximum age of cache file in seconds (!) before it gets reloaded (set to 0 to never renew files, default: 2592000 = 30 days)
• force Force update (set to 1 or any other non-empty value)

Defaults may be changed by setting environmental variables when running goggle.

Environmental variables

Changes defaults and sets some other elements:

• GOGGLER_WIDTH Set default image width
• GOGGLER_HEIGHT Set default image height
• GOGGLER_SCALE Set default image scale
• GOGGLER_QUALITY Set default image quality
• GOGGLER_WAIT_FOR_IDLE Wait for network idle in browser (default: false, set to any value to enable)
• GOGGLER_WAIT Set default wait time (ms) before rendering (default: 2000 aka 2 seconds)
• GOGGLER_TIMEOUT Set default timeout (ms) time (default: 60000 aka 60 seconds)
• GOGGLER_MAXAGE Set default max age (s) time (default: 2592000 aka 30 days)
• GOGGLER_LISTEN Set default listen address (default: :8080)
• GOGGLER_DEBUG Enable debugging log (default: false, set to any value to enable)
• GOGGLER_CACHE Type of cache (local or s3, default local)
• GOGGLER_CACHE_CLEANUP_INTERVAL Interval in seconds at which cleanup service is run to clean stale data (maxage has to be greater than 0, also: set to 0 to never clean up old files, s3 needs full days to work properly, default: 2592000 = 30 days)
• GOGGLER_CACHE_LOCAL_PATH Path to local cache (default: OS specific temp dir like /tmp/goggler)
• GOGGLER_CACHE_S3_URL Endpoint for S3 storage (e.g. s3.amazonaws.com)
• GOGGLER_CACHE_S3_BUCKETNAME Bucket name
• GOGGLER_CACHE_S3_ACCESSKEY Access Key ID for S3 storage
• GOGGLER_CACHE_S3_SECRETKEY Secret Access Key ID for S3 storage
• GOGGLER_CACHE_S3_REGION S3 region (might be skipped in Amazon, e.g. us-east-1)
• GOGGLER_CACHE_S3_SKIPSSL Set to any value to skip secure SSL/TLS connection
• GOGGLER_CACHE_S3_CREATEBUCKET Set to any value to create bucket if it does not exist

Examples:

# Basic test
GOGGLER_DEBUG=1 GOGGLER_LISTEN=127.0.0.1:9090 ./goggler
# Local storage
GOGGLER_CACHE_LOCAL_PATH=~/mydata ./goggler
# Waiting for network idle instead of fixed amount of time
GOGGLER_CACHE_LOCAL_PATH=~/mydata GOGGLER_WAIT_FOR_IDLE=1 ./goggler
# S3 storage
GOGGLER_DEBUG=1 GOGGLER_CACHE=s3 GOGGLER_CACHE_S3_BUCKETNAME=mytestbucket \
  GOGGLER_CACHE_S3_ACCESSKEY=_KEY_ GOGGLER_CACHE_S3_SECRETKEY=_KEY_ ./goggler
# Minio storage
GOGGLER_DEBUG=1 GOGGLER_CACHE=s3 GOGGLER_CACHE_S3_URL=127.0.0.1:9000 \
  GOGGLER_CACHE_S3_BUCKETNAME=test GOGGLER_CACHE_S3_ACCESSKEY=minioadmin \
  GOGGLER_CACHE_S3_SECRETKEY=minioadmin GOGGLER_CACHE_S3_SKIPSSL=1 \
  GOGGLER_CACHE_S3_CREATEBUCKET=1 ./goggler

Docker

There is a Docker container of goggler including a headless version of Chromium. Try it using:

docker run --rm -p8080:8080 --init ronix/goggler

Important: The --init option is needed to get rid of zombie processes that will spawn if you run the container. This is due Chrome creating new processes within the container. I have not found a way to tackle this, but since it is more a feature than a bug, I assume we can live with this.

Full example with persistent volume:

docker run -d -p8080:8080 -v /tmp/goggler:/tmp/goggler \
  --name goggler --init ronix/goggler

Full example with S3 storage:

docker run -d -p8080:8080 --name goggler -e "GOGGLER_CACHE=s3" \
  -e "GOGGLER_CACHE_S3_BUCKETNAME=mytestbucket" \
  -e "GOGGLER_CACHE_S3_ACCESSKEY=_KEY_" \
  -e "GOGGLER_CACHE_S3_SECRETKEY=_KEY_" \
  --init ronix/goggler

Building Docker image from this source:

docker build -t goggler .