https://wiki.debian.org/DebianRepository/Format#Signed-By says:
> **Signed-By**
> An optional field containing a comma separated list of
> OpenPGP key fingerprints to be used for validating
> the next Release file. The fingerprints must consist
> only of hex digits and may not contain spaces.
> The fingerprint specifies either the key the Release file
> must be signed with or the key the signature key must be
> a subkey of. The later match can be disabled by appending
> an exclamation mark to the fingerprint.
>
> If the field is present, a client should only accept future updates
> to the repository that are signed with keys listed in the field.
> The field should be ignored if the Valid-Until field is not present
> or if it is expired.
For both the CLI tools and JSON, the field is taken as a string verbatim.
When specified, we must also provide `Valid-Until` field,
and i'm not sure there is an 'infinity' value for it,
so 100 years will have to do?
Fixes https://github.com/aptly-dev/aptly/issues/1497
This change makes it possible to publish multiple distributions
with packages named the same but with different content by changing
structure of the generated pool hierarchy. The option not enabled
by default as this changes the structure of the output which could
break the expectations of other tools.
While testing out Aptly, the `apt-get` client complains with the following error, since the `codename` was switched from the InRelease files that are baked out by Aptly:
```
E: Repository 'http://debianrepo.example.com/bionic testing InRelease' changed its 'Codename' value from '' to 'testing'
```
The added "aptly publish repo" option "-access-by-hash" publishes
the index files (Packages*, Sources*) also as hardlinked hashes.
Example:
/dists/yakkety/main/binary-amd64/by-hash/SHA512/31833ec39acc...
The Release files indicate this with the option "Acquire-By-Hash: yes"
This is used by apt >= 1.2.0 and prevents the "Hash sum mismatch" race
condition between a server side "aptly publish repo" and "apt-get update"
on a client.
See: http://www.chiark.greenend.org.uk/~cjwatson/blog/no-more-hash-sum-mismatch-errors.html
This implementation uses symlinks in the by-hash/*/ directory for keeping
only two versions of the index files and deleting older files
automatically.
Note: this only works with aptly.FileSystemPublishedStorage
Closes: #536
Signed-off-by: André Roth <neolynx@gmail.com>
