Example tag name: `git-/github.com/docker/notary-official-images-refs/tags/v0.5.0-FETCH_HEAD`
Referring to:
```
signer-0.5.0: git://github.com/docker/notary-official-images@v0.5.0 notary-signer
```
- only print a Constraints-related "skipping" warning for a given "repo:tag" once per session
- apply constraints while sorting too (so that `bashbrew build --all` on Windows doesn't try to `git fetch` Linux rootfs tarballs only to skip them during build, for example)
- add `--apply-constraints` flag to `from`, `children`, and `parents` subcommands
Move "build order" sorting functions into a common file and refactor them to use topsort properly and via a single unified function (single node per logical "thing" we're sorting, resolve tag names to canonical node names appropriately)
This changes something like:
Using bashbrew/cache:2775145643e397ca993e842f3263a1362a49df4115ce59d59bed1452323b7af2 (buildpack-deps)
into:
Using bashbrew/cache:2775145643e397ca993e842f3263a1362a49df4115ce59d59bed1452323b7af2 (buildpack-deps:wheezy)
- like the following to get golang:latest and the cache name of its parent
```console
$ bashbrew cat --format '{{ range .Entries }}{{ $.DockerCacheName . }}{{ range .Tags }}{{"\n"}}{{ join ":" $.RepoName . }}{{end}}{{"\n"}}{{end}}' golang:latest
```
To satisfy both Windows (https://github.com/docker-library/golang/pull/92) building and "non-AUFS" (https://github.com/docker-library/official-images/pull/1612, https://github.com/docker-library/official-images/pull/1537) building ("build machine" constraints, if you will), an update to the manifest file format is necessary.
To this end, we're introducing a new format which uses RFC 2822, allowing much more expressivity (especially for additional metadata like `Constraints`) and readability. The new tool also includes backwards compatibility for the older line-based manifest file format, but its usage is discouraged (and we will be slowly converting at least the `docker-library` repos to use the new format in their `generate-stackbrew-library.sh` scripts).
One of the tangential benefits of this conversion is a massive increase in the speed of the tool (`bashbrew list --all` on a very fast system with an SSD and a flaming hot cache used to take ~5s and now takes ~0.012s).
Tianon Gravi