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Throw a userError, exiting the program with the supplied message.

Print an error message to stderr and return a non-zero exit code, the message is prefixed with the name of the program.

Print the bytestring to stdout if the first argument is Nothing, otherwise write the bytestring to the provided filesystem path and print the path to stdout.

Combine an image name and a base path producing an output path.

Combine an image name, an image tag, and a base path producing an output path with a -config.json suffix.

Combine an image name, an image tag, and a base path producing an output path with a -manifest.json suffix.

Join a list of strings and the path part of a RegistryURI to produce a new RegistryURI with a path root of /v2.

Given a Auth produce a Options.

Hash a Char8 using the SHA256 algorithm.

Strip the sha256: identifier prefix from a hash digest.

Encode, following Docker's canonical JSON rules, any ToJSON data type.

The canonicalization rules enable consistent hashing of encoded JSON, a process relied upon heavily by docker for content addressability and unique identification of resources within a docker registry. Notably, an image's config JSON file and layers.

NB: Docker's canonical JSON spec intentionally *does not* follow the OLPC's Canonical JSON format even though it was inspired by it.

Throw an error if the first argument is Nothing, otherwise return the FilePath unwrapped.

Pluck out the digest value for the config JSON given a docker registry image manifest. Attempting to parse and return the digest value as a SHA256, otherwise throw an error.

Split a docker image's name on the forward slash separator so we get the distinct repo name and image name.

Given a nix expression AST, produce a pretty printer document.

Print a nix expression AST using the renderNixExpr pretty printing renderer.

Given an executable's name, try to find it in the PATH.