Using SCache with Buildless

SCCache is the spiritual successor to CCache, rewritten in Rust with an emphasis on distributed compile execution as well as caching. It is primarily used with the Rust toolchain, but can be used with nearly any C-like toolchain, like CCache.

Selecting a backend

SCCache supports many backends, including an HTTP-based backend and direct use of Redis.

HTTP ("Webdav") backend

SCCache provides the WebDAV adapter for plain HTTP or HTTP+TLS remote backends; it uses the SCCACHE_WEBDAV_* set of variables, which should be set as demonstrated below:

Variable	Value
`SCCACHE_WEBDAV_ENDPOINT`	`https://sccache.less.build/cache/generic`
`SCCACHE_WEBDAV_USERNAME`	`apikey` (Literal value)
`SCCACHE_WEBDAV_PASSWORD`	Your API key

The HTTP backend is great because it is easy to understand, monitor, and diagnose; in some cases, though, the Redis-based adapter may perform better.

Redis backend

SCCache also supports caching via Redis-compliant backends. Buildless API endpoints natively speak Redis protocol. To configure this backend, you'll use the SCCACHE_REDIS variable, which specifies a formatted connection URL. Here's an example:

Variable	Value
`SCCACHE_REDIS`	`rediss://apikey:{your key}@redis.less.build:6379`

Let's break this URL down into components:

Component	Meaning	Notes
`rediss://`	Activate TLS	Buildless uses TLS with publicly-verifiable certificates.
`apikey`	Redis username	The literal string `apikey`, or a specific org tenant ID.
`{your key}`	Redis password	Your API key should be used in this field.
`redis.less.build`	Endpoint	Traffic endpoint.
`6379`	Port	Buildless uses the standard Redis port, `6379`.

For more information about using Redis with Buildless, see our Buildless + Redis guide.

S3 backend

SCCache can also use S3-compatible APIs as remote storage. Buildless provides support for S3 on a dedicated endpoint. To configure this backend, set the following variable values on your environment:

Variable	Value	Notes
`SCCACHE_ENDPOINT`	`https://sccache.less.build/cache/s3`	-
`SCCACHE_BUCKET`	<Your bucket name>	The name should be unique within your account.
`AWS_ACCESS_KEY_ID`	<API Key ID>	The public ID for your API Key should be used.
`AWS_SECRET_ACCESS_KEY`	<API Key value>	The literal API Key value should be used in this field.

See our S3 REST API documentation for a full compatibility guide.