How to generate the `Release` file on a local package repository?

Question

CONTEXT

With a local package repository, I'm able to provide my APT instances with a set of software packages and configurations from a server which I control, allowing any client to install this software using just the normal apt install command (providing the repository is added to their /etc/apt/sources.list{,.d/}).

For my attempt at creating a local package repository, I followed this tutorial on bipmedia.com, which roughly consists of:

1. Generate the .deb
2. Store the .deb on an Apache2 web server
3. Generate a Package.gz file

My Attempt

Generating the binary package file

To generate the .deb, the software files are required, a DEBIAN folder with metadata is generated and the following command compiles the code and assembles the package:

dpkg-deb --build [source code tree with DEBIAN directory]

Serve repository files with Apache2 server

I'm skipping this part as it's unrelated to the problem I'm seeking to solve with this question.

Generating a Packages.gz file (repository metadata)

With the an open shell instance whose working directory is the Apache server root folder containing the .deb file from above, I called:

dpkg-scanpackages debian /dev/null | gzip -9c >debian/Packages.gz

PROBLEM

Calling apt update on the client machine, it complains with:

W: The repository 'http://example.com packages/ Release' does not have a Release file.

This necessary file is missing in my local repository. It seems to be a register of package checksums, but after searching on the Internet, my very limited understanding of the topic kept me from being able to find out how to generate it.

---

Note: My /etc/apt/sources.list file does have the following line:

deb http://example.com packages/

QUESTION

How do I generate the Release file for a local APT package repository?

Solution

There are a number of ways of going about this; I use apt-ftparchive.

1. Create an aptftp.conf file in the root of your repository:

   APT::FTPArchive::Release {
     Origin "Your origin";
     Label "Your label";
     Suite "unstable";
     Codename "sid";
     Architectures "amd64 i386 source";
     Components "main";
     Description "Your description";
   };
   

   with the appropriate values (change “Origin”, “Label”, “Description” at least, and adjust “Architectures” to match the binaries you host).

2. Create a matching aptgenerate.conf file alongside:

   Dir::ArchiveDir ".";
   Dir::CacheDir ".";
   TreeDefault::Directory "pool/";
   TreeDefault::SrcDirectory "pool/";
   Default::Packages::Extensions ".deb";
   Default::Packages::Compress ". gzip bzip2";
   Default::Sources::Compress ". gzip bzip2";
   Default::Contents::Compress "gzip bzip2";
   
   BinDirectory "dists/unstable/main/binary-amd64" {
     Packages "dists/unstable/main/binary-amd64/Packages";
     Contents "dists/unstable/Contents-amd64";
     SrcPackages "dists/unstable/main/source/Sources";
   };
   
   BinDirectory "dists/unstable/main/binary-i386" {
     Packages "dists/unstable/main/binary-i386/Packages";
     Contents "dists/unstable/Contents-i386";
     SrcPackages "dists/unstable/main/source/Sources";
   };
   
   Tree "dists/unstable" {
     Sections "main"; # contrib non-free";
     Architectures "amd64 i386 source";
   };
   

   (removing i386 if you don’t need that).

3. In your repository, clear the database:

   rm -f packages-i386.db packages-amd64.db
   

4. Generate the package catalogs:

   apt-ftparchive generate -c=aptftp.conf aptgenerate.conf
   

5. Generate the Release file:

   apt-ftparchive release -c=aptftp.conf dists/unstable >dists/unstable/Release
   

6. Sign it:

   gpg -u yourkeyid -bao dists/unstable/Release.gpg dists/unstable/Release
   gpg -u yourkeyid --clear-sign --output dists/unstable/InRelease dists/unstable/Release
   

   (with the appropriate id instead of yourkeyid).

Whenever you make a change to the repository, you need to run steps 3 to 6 again.

Comments

[Toby]

Can you use something like ` dpkg-scanpackages` rather than apt-ftparchive?

[Stephen Kitt]

@Toby you can use dpkg-scanpackages to generate the package catalogs, but it won’t handle Release for you. The simple option nowadays is probably aptly; I should re-write this answer using that.

[Toby]

Awesome! Thanks. I should have said earlier, I was looking for a cross platform tool which apt-ftparchive seems like it's not. So aptly sounds good for me and I'll read up on creating the packages. I'm assuming the signing is separate anyway.

[ironman]

I have done exactly this, with focal instead of unstable everywhere, and amd64 only, and my custom deb file is in dists/focal/main/binary-amd64, but when I run step 4, may Packages file in dists/focal/main/binary-amd64 is empty, zero size. And if I try to install the binary on another computer, it does not find the package...