gcs-helper

README

gcs-helper

gcs-helper is inspired by s3-helper and is used to provide access to private GCS buckets.

It's intended to be deployed along with Kaltura's nginx-vod-module.

It also provides the needed support for the mapped mode (when using the proper environment variables - GCS_HELPER_PROXY_PREFIX, GCS_HELPER_MAP_PREFIX and GCS_HELPER_MAP_EXTENSIONS).

Configuration

The following environment variables control the behavior of gcs-helper:

Variable	Default value	Required	Description
GCS_HELPER_LISTEN	:8080	No	Address to bind the server
GCS_HELPER_BUCKET_NAME		Yes	Name of the bucket
GCS_HELPER_LOG_LEVEL	debug	No	Logging level
GCS_HELPER_PROXY_PREFIX		No	Prefix to use for the proxy binding. Required if running in map and proxy modes (example value: /proxy/)
GCS_HELPER_PROXY_TIMEOUT	10s	No	Defines the maximum time in serving the proxy requests, this is a hard timeout and includes retries
GCS_HELPER_MAP_PREFIX		No	Prefix to use for the map binding. Required if running in map and proxy modes (example value: /map/)
GCS_HELPER_MAP_EXTENSIONS		No	Comma separated list of extensions to include in the mapping (example value: .mp4,.vtt,.srt)
GCS_HELPER_EXTRA_RESOURCES_TOKEN			Token to be used as query string parameter on the map location to pass extra resources to the mapping
GCS_HELPER_MAP_EXTRA_PREFIXES		No	Comma separated list of prefixes that allow gcs-helper to lookup files in different paths

The are also some configuration variables for network communication with Google Cloud Storage API:

Variable	Default value	Required	Description
GCS_CLIENT_TIMEOUT	2s	No	Hard timeout on requests that gcs-helper sends to the Google Storage API
GCS_CLIENT_IDLE_CONN_TIMEOUT	120s	No	Maximum duration of idle connections between gcs-helper and the Google Storage API
GCS_CLIENT_MAX_IDLE_CONNS	10	No	Maximum number of idle connections to keep open. This doesn't control the maximum number of connections

GCS_HELPER_PROXY_TIMEOUT x GCS_CLIENT_TIMEOUT

The timeout configuration is mainly controlled by two environment variables: GCS_HELPER_PROXY_TIMEOUT and GCS_CLIENT_TIMEOUT. The GCS_HELPER_PROXY_TIMEOUT controls how long requests to gcs-helper can take, and GCS_CLIENT_TIMEOUT controls how long requests from gcs-helper to Google's API can take. Since gcs-helper automatically retries on failures, the number of retries is roughly the value of GCS_HELPER_PROXY_TIMEOUT divided by the value of GCS_CLIENT_TIMEOUT.

GCS_HELPER_EXTRA_RESOURCES_TOKEN

The extra resources token is the query string parameter that the mapping location will look for to add external resources to the JSON output.

For example, giving that you set GCS_HELPER_EXTRA_RESOURCES_TOKEN to extras, you'll be able to add videos and captions files that are in different bucket by calling the map location with ?extras=/bucket-1/file.mp4,/bucket-2/pt-br.vtt.