* use the cachekey of the src stage rather than the digest
for COPY --from commands as they are reproducible unlike digests
* track digest to cache keys and stage indexes to digest
* add extra debug logging for troubleshooting cachekey building issues
* convert Sha256 hashes to hex encoded strings rather than plain strings
for easier human reading
Store the last cachekey generated for each stage
If the base image for a stage is present in the map of digest
and cachekeys use the retrieved cachekey instead of the base image
digest in the compositecache
Fixed#296.
The output manifests may have `application/vnd.docker.distribution.manifest.v2+json`
as their media types instead of `application/vnd.oci.image.manifest.v1+json`.
Resolves#607
* Deleted a duplicate Gopkg.lock block for github.com/otiai10/copy to
prevent `dep ensure` from deleting it from vendor/
* Searched for breaking changes. Only found ones for
remote.Delete/List/Write/WriteIndex. Searched for those and fixed
* Noticed that NewInsecureRegistry was deprecated and replaced it
* Revert "Change cache key calculation to be more reproducible. (#525)"
This reverts commit 1ffae47fdd.
* Add logging of composition key back
* Do not include build args in cache key
This should be save, given that the commands will have the args included
when the cache key gets built.
This flag, when set, takes a file in the container and writes the image digest to it. This can be used to extract the exact digest of the built image by surrounding tooling without having to parse the logs from Kaniko, for example by pointing the file to a mounted volume or to a file used durint exit status, such as with Kubernetes' [Termination message policy](https://kubernetes.io/docs/tasks/debug-application-cluster/determine-reason-pod-failure/)]
When the flag is not set, the digest is not written to file and the executor behaves as before. The digest is also written to file in case of a tarball or a `--no-push`.
Closes#654