If you want to use Object Storage Service (aka OSS) by Alibaba for the sccache cache, you need to set the SCCACHE_OSS_BUCKET environment variable to the name of the OSS bucket to use.
You must specify the endpoint URL using the SCCACHE_OSS_ENDPOINT environment variable. More details about OSS endpoints.
You can also define a prefix that will be prepended to the keys of all cache objects created and read within the OSS bucket, effectively creating a scope. To do that use the SCCACHE_OSS_KEY_PREFIX environment variable. This can be useful when sharing a bucket with another application.
Sccache is able to load credentials from environment variables: ALIBABA_CLOUD_ACCESS_KEY_ID and ALIBABA_CLOUD_ACCESS_KEY_SECRET.
Alternatively, the SCCACHE_OSS_NO_CREDENTIALS environment variable can be set to use public readonly access to the OSS bucket, without the need for credentials. Valid values for this environment variable are true, 1, false, and 0. This can be useful for implementing a readonly cache for pull requests, which typically cannot be given access to credentials for security reasons.