Probe an Upload Destination's Credentials and Connectivity

The front-door check, dispatched on the upload object's class, that confirms before any compute whether the destination is reachable and the credentials are in the right place (TARGETS-DESIGN.md section 6.1). Run it as a one-liner at the prompt before tar_make() - it is the user's explicit preflight. ssd_scenario_targets() deliberately does not call it (the factory does no network I/O, so sourcing _targets.R stays side-effect free); a missing credential still fails loud per-shard at ssd_upload_shard() time as a backstop.

Usage

ssd_test_upload(upload)

Arguments

upload

An upload destination from ssd_upload_azure() or ssd_upload_dryrun().

Value

NULL, invisibly (called for its side effect: the probe).

Details

For an Azure destination it resolves the credentials from the environment and, when a required variable is absent, aborts with a loud error naming the missing variable (rather than failing later on a worker); when they are present it lists the container and writes then deletes a small marker blob, returning invisibly on success and aborting with the backend's diagnostic on failure. For a dry-run destination it succeeds trivially without resolving credentials or reaching any network.

See also

ssd_upload_shard(), ssd_open_uploaded(), ssd_upload_azure().

Examples

ssd_test_upload(ssd_upload_dryrun())