Packaging Go application for Debian - go

How can I put my Go binary into a Debian package? Since Go is statically linked, I just have a single executable--I don't need a lot of complicated project metadata information. Is there a simple way to package the executable and resource files without going through the trauma of debuild?
I've looked all over for existing questions; however, all of my research turns up questions/answers about a .deb file containing the golang development environment (i.e., what you would get if you do sudo apt-get install golang-go).

Well. I think the only "trauma" of debuild is that it runs lintian after building the package, and it's lintian who tries to spot problems with your package.
So there are two ways to combat the situation:
Do not use debuild: this tool merely calls dpkg-buildpackage which really does the necessary powerlifting. The usual call to build a binary package is dpkg-buildpackage -us -uc -b. You still might call debuild for other purposes, like debuild clean for instance.
Add the so-called "lintian override" which can be used to make lintian turn a blind eye to selected problems with your package which, you insist, are not problems.
Both approaches imply that you do not attempt to build your application by the packaging tools but rather treat it as a blob which is just wrapped to a package. This would require slightly abstraining from the normal way debian/rules work (to not attempt to build anything).
Another solution which might be possible (and is really way more Debian-ish) is to try to use gcc-go (plus gold for linking): since it's a GCC front-end, this tool produces a dynamically-linked application (which links against libgo or something like this). I, personally, have no experience with it yet, and would only consider using it if you intend to try to push your package into the Debian proper.
Regarding the general question of packaging Go programs for Debian, you might find the following resources useful:
This thread started on go-nuts by one of Go for Debian packagers.
In particular, the first post in that thread links to this discussion on debian-devel.
The second thread on debian-devel regarding that same problem (it's a logical continuation of the former thread).
Update on 2015-10-15.
(Since this post appears to still be searched and found and studied by people I've decided to update it to better reflec the current state of affairs.)
Since then the situation with packaging Go apps and packages got improved dramatically, and it's possible to build a Debian package using "classic" Go (the so-called gc suite originating from Google) rather than gcc-go.
And there exist a good infrastructure for packages as well.
The key tool to use when debianizing a Go program now is dh-golang described here.

I've just been looking into this myself, and I'm basically there.
Synopsis
By 'borrowing' from the 'package' branch from one of Canonical's existing Go projects, you can build your package with dpkg-buildpackage.
install dependencies and grab a 'package' branch from another repo.
# I think this list of packages is enough. May need dpkg-dev aswell.
sudo apt-get install bzr debhelper build-essential golang-go
bzr branch lp:~niemeyer/cobzr/package mypackage-build
cd mypackage-build
Edit the metadata.
edit debian/control file (name, version, source). You may need to change the golang-stable dependency to golang-go.
The debian/control file is the manifest. Note the 'build dependencies' (Build-Depends: debhelper (>= 7.0.50~), golang-stable) and the 3 architectures. Using Ubuntu (without the gophers ppa), I had to change golang-stable to golang-go.
edit debian/rules file (put your package name in place of cobzr).
The debian/rules file is basically a 'make' file, and it shows how the package is built. In this case they are relying heavily on debhelper. Here they set up GOPATH, and invoke 'go install'.
Here's the magic 'go install' line:
cd $(GOPATH)/src && find * -name '*.go' -exec dirname {} \; | xargs -n1 go install
Also update the copyright file, readme, licence, etc.
Put your source inside the src folder. e.g.
git clone https://github.com/yourgithubusername/yourpackagename src/github.com/yourgithubusername/yourpackagename
or e.g.2
cp .../yourpackage/ src/
build the package
# -us -uc skips package signing.
dpkg-buildpackage -us -uc
This should produce a binary .deb file for your architecture, plus the 'source deb' (.tgz) and the source deb description file (.dsc).
More details
So, I realised that Canonical (the Ubuntu people) are using Go, and building .deb packages for some of their Go projects. Ubuntu is based on Debian, so for the most part the same approach should apply to both distributions (dependency names may vary slightly).
You'll find a few Go-based packages in Ubuntu's Launchpad repositories. So far I've found cobzr (git-style branching for bzr) and juju-core (a devops project, being ported from Python).
Both of these projects have both a 'trunk' and a 'package' branch, and you can see the debian/ folder inside the package branch. The 2 most important files here are debian/control and debian/rules - I have linked to 'browse source'.
Finally
Something I haven't covered is cross-compiling your package (to the other 2 architectures of the 3, 386/arm/amd64). Cross-compiling isn't too tricky in go (you need to build the toolchain for each target platform, and then set some ENV vars during 'go build'), and I've been working on a cross-compiler utility myself. Eventually I'll hopefully add .deb support into my utility, but first I need to crystallize this task.
Good luck. If you make any progress then please update my answer or add a comment. Thanks

Building deb or rpm packages from Go Applications is also very easy with fpm.
Grab it from rubygems:
gem install fpm
After building you binary, e.g. foobar, you can package it like this:
fpm -s dir -t deb -n foobar -v 0.0.1 foobar=/usr/bin/
fpm supports all sorts of advanced packaging options.

There is an official Debian policy document describing the packaging procedure for Go: https://go-team.pages.debian.net/packaging.html
For libraries: Use dh-make-golang to create a package skeleton. Name your package with a name derived from import path, with a -dev suffix, e.g. golang-github-lib-pq-dev. Specify the dependencies ont Depends: line. (These are source dependencies for building, not binary dependencies for running, since Go statically links all source.)
Installing the library package will install its source code to /usr/share/golang/src (possibly, the compiled libraries could go into .../pkg). Building depending Go packages will use the artifacts from those system-wide locations.
For executables: Use dh-golang to create the package. Specify dependencies in Build-Depends: line (see above regarding packaging the dependencies).

I recently discovered https://packager.io/ - I'm quite happy with what they're doing. Maybe open up one of the packages to see what they're doing?

Related

Debian package project

In school we had to choose a project in shell script. I have choose the 17th which is about listing Debian packages and solve some tasks with it but in school we didn't get any good advice or anything like that to start it and I would like to ask for some ideas how could I do it or even start it.
Some details about the project:
List of Debian packages:
Under Debian, ask which packages are installed on the machine, enter the names of these packages in a formatted format, and the program will also write which programs a particular package depends on.
For example.
nparted: libc6, libnewt0, libparted1.4, libuuid1
nano: libc6, libncurses5
I successfully did the package listing, but I don't know how could I move forward.
apt-cache depends <package> shows the dependencies (Depends, Recommends and Suggests) of a package.
Alternatively, apt show <package> writes the control file of a package.
The two commands have different output formats, so you can pick one that you find easier to parse.

How to install golang-libguestfs package?

I am trying to install the libguestfs package for golang but couldn't find the way to do so. I went through this but it didn't work for me and I believe it's empty. I see only test files here
Following is the content of the README
$GOPATH
-------
http://golang.org/doc/code.html
Note that $GOPATH is set (by the ./run script) to the
libguestfs/golang directory so that "installs" happen in the local
build tree.
From this I could figure out that I need to build the package but again for that, I couldn't find some help or proper document.
Is there any way to do the installation? I am using RHEL 7.7
Libguestfs (the C library) is packaged already in RHEL 7, so I would suggest first of all installing that using yum install libguestfs. That's the version that Red Hat supports.
We don't ship the golang bindings, not even in RHEL 8. Furthermore the bindings in all languages are generated from a mechanical description of the API and thus not stored directly inside our git repository. That's why you could only find test files in git.
However we do distribute the generated files in the tarballs, so an easy way is to grab the latest tarball from https://download.libguestfs.org/1.42-stable/ and look in the golang/src/libguestfs.org/guestfs subdirectory of the tarball.
The harder way is to generate them from git. These steps worked for me on RHEL 7.7, YMMV:
sudo yum-builddep libguestfs
git clone https://github.com/libguestfs/libguestfs
cd libguestfs
git submodule init
git submodule update
./bootstrap
./autogen.sh SUPERMIN=/usr/bin/supermin5
make
and again look in the golang/ subdirectory.
I'm reasonably sure that golang bindings from one version should work with another version of the C library. We did test this at one point in time, so if it's no longer true then it may have regressed as these things sometimes do.

How to build/install cross-compiled nested packages quickly?

I have a repository with a group of nested go packages organized as follows:
$GOPATH/src/
- mypackage/common/utils.go
- mypackage/app1/main.go
- mypackage/app2/main.go
...
It compiles to a handful of binaries. For releasing, I'm cross-compiling for a multitude of platforms/archs (I deploy repeatedly with a different GOOS and GOARCH). I'm trying to write the compilation results to a directory of my choice, but I'm fighting with the toolchain.
I can:
Combine GOBIN and go install when compiling for my own architecture
(i.e. not cross compiling):
# build + output all binaries in /somedir/bin
# this works great when compiling for my local architecture.
GOBIN=/somedir/bin go install mypackage/app1 mypackage/app2 mypackage/app3
But unfortunately, GOBIN conflicts with cross-compilation e.g:
# Throws: "cannot install cross-compiled binaries when GOBIN is set"
GOBIN=/somedir/bin GOARCH=amdm64 GOOS=darwin go install mypackage/app1 mypackage/app2
Use go build with GOOS=X and GOARCH=Y for each subpackage
# cross compile one of the binaries
cd /output/darwin-386-bin/ && \
GOOS=darwin GOARCH=386 go build mypackage/app1
# but if given multiple binaries, there is no output. (as documented)
GOOS=darwin GOARCH=386 go build mypackage/app1 mypackage/app2
When go build is given multiple packages, it no longer emits binaries -- it just checks that the code compiles. To emit all the binaries, it seems I have to run go build once for each subpackage, so it takes longer, esp when building with -a.
Another possible issue with using go build like this, is that it's potentially mixing binaries and intermediary results across multiple architectures in the same workspace. But maybe that's just a matter of taste. Hopefully the toolchain keeps cached results separate for different architectures.
How is this handled in practice? Should I treat each subpackage as an individual package, despite their shared common code (would it then be safe to build them all in parallel)?
Related articles:
go build vs go install: https://groups.google.com/forum/#!topic/golang-nuts/s8Csz3-7EXA (Little info on cross-compilation, or multipackage setups)
cross compile with go 1.5.: https://dave.cheney.net/2015/08/22/cross-compilation-with-go-1-5 (does not specifically address multipackage / common code compilation. Also, the statement about having to recompile the standard library into /usr/local/go/pkg seems to no longer hold in 1.9.1, as far as I can tell)
Go build multiple nested packages: Go build multiple/nested packages? . ( The accepted answer, go build ./... behaves the same as passing multiple packages in a single build command, and therefore outputs no binaries. The thread also does not cover cross compilation)
What I'm about to suggest feels like a hack at best, but it might work for you if you're cross-compiling stuff in a container or an isolated build environment.
You can drop the GOBIN from the install command:
# I'm not on this platform, so this is a cross compile
GOOS=darwin GOARCH=amd64 go install mypackage/app1 mypackage/app2
Assuming your package is in $GOPATH/src/mypackage the above command will install the two binaries to:
$GOPATH/bin/darwin_amd64/{app1, app2}
and the .a compile dependency files in:
$GOPATH/pkg/darwin_amd64/mypackage/{app1,app2,common}
If you're running this in a for loop for all the platforms you plan on supporting, one nuisance with this process is that when you pass GOOS=x GOARCH=y matching your local architecture (i.e. not cross compiling), then the executables will be placed directly in $GOPATH/bin/ and not $GOPATH/bin/x_y/.
(packages on the other hand always end up in $GOPATH/pkg/x_y/, cross compilation or not).
To determine your local architecture, you can follow steps in this answer: https://stackoverflow.com/a/35669816/5556676 .
Simulating GOBIN=/foo/bin GOOS=x GOARCH=y go install mypackage/app{1,2,3}
Changing $GOPATH has little effect on where go install writes output. With some go commands, like go get, you tweak where packages are installed by adding a new component at the front of $GOPATH. But in go 1.9, go install will always copy binaries in the bin/ folder that's a sibling of the src/ which contains the packages to install.
Instead of using GOBIN=/foo/bin, you can pretend your source files are in /foo/src/mypackage (you may use a symlink), and then do GOPATH=/foo GOOS=x GOARCH=y go install mypackage/app{1,2,3}. This will put binaries in /foo/bin, because of the behavior I describe in the previous paragraph.
It's probably simpler to just grab the binaries from where you expect them to be though, than mucking with copying source trees around.

Go lang: how to install libxml2/gokogiri on windows

If there a relatively simple way to make go + libxml2 + gokogiri work on windows?
I mean that I may be can install it (but at the moment I can not, stuck with Package libxml-2.0 was not found in the pkg-config search path), but then I need to provide my utilite to other people, who will never be able (or would wish ) to install lall libxml2 dependencies, modify PATH etc on windows...
It work flawless on Ubuntu...
I found this https://github.com/moovweb/gokogiri/issues/49 thats funny with installation of Gimp 2 (what?!), but I still cannot make it run with such error, I guess might be issue with PATH, but all PATH are set
$ go get github.com/moovweb/gokogiri
# github.com/moovweb/gokogiri/help
Documents\go\src\github.com\moovweb\gokogiri\help\help.go:6:25: fatal error: lib
xml/tree.h: No such file or directory
#include <libxml/tree.h>
^
compilation terminated.
# github.com/moovweb/gokogiri/xpath
Documents\go\src\github.com\moovweb\gokogiri\xpath\expression.go:4:26: fatal err
or: libxml/xpath.h: No such file or directory
#include <libxml/xpath.h>
^
compilation terminated.
You are struggling because it is hard to combine packages that were built by different people for different purposes and get your environment set up correctly. I think it is best to use MSYS2, an environment for Windows that provides a consistent set of packages for things like gcc, go, libxml2, and iconv. MSYS2 has a package manager (pacman) that helps you easily install them and keep them updated.
I don't do much programming with Go, but I am familiar with MSYS2 and it seems like I was able to get gokogiri installed using MSYS2. You should open MSYS2's "MinGW-w64 Win64 Shell" from the Start menu (mingw64_shell.bat), and try running these commands:
pacman -S mingw-w64-x86_64-{gcc,go,libxml2,iconv}
export GOROOT=/mingw64/
export GOPATH=/c/Users/David/Documents/goproj/
mkdir -p $GOPATH
go get github.com/moovweb/gokogiri
I think GOPATH should be set to the directory of your project. If you run into an error, it might be because some pacman package is required that I didn't list here.
The string mingw-w64-x86_64-{gcc,go,libxml2,iconv} gets expanded by Bash into the following list of packages:
mingw-w64-x86_64-gcc
mingw-w64-x86_64-go
mingw-w64-x86_64-libxml2
mingw-w64-x86_64-iconv
If you are actually using 32-bit Windows, replace x86_64 with i686 in the instructions above.
If you are curious, the scripts for building those packages are here: https://github.com/Alexpux/MINGW-packages
As a disclaimer, I haven't actually compiled any go programs in MSYS2, so there could be big problems I am unaware of.
Also, one of the main developers of MSYS2 (alexpux) said this in the #msys2 IRC chat on 2015-06-21:
We not build go for a long time.
This package in very WIP state
Also see
https://github.com/Alexpux/MINGW-packages/issues/421
So you might need to fix some issues with the MSYS2 Go package and recompile it yourself to really make this work. But you have the PKGBUILD script that was used to build it, so maybe that will be less hard than what you are trying to do right now, which involves compiling/collecting every dependency of gokogiri.
MSYS2 would make your other installation of go, libxml2, and iconv obsolete. You can delete those things once you get your MSYS2 environment working.
If you are using visual studio and want to add dependency to your project then just install it using NuGet Package Manager it's easiest method.
Install command: Install-Package libxml2

"go build" became very slow after installing a new version of Go

After upgrading from Go 1.2.1 to 1.3 (Windows 7 64 bit) "go build" execution time has increased from around 4 to over 45 seconds. There were no other changes except the go version update. Switching off the virus scanner seems to have no effect. Any clues?
You probably have dependencies that are being recompiled each time. Try go install -a mypackage to rebuild all dependencies.
Removing $GOPATH/pkg also helps to ensure you don't have old object files around.
Building with the -x flag will show you if the toolchain is finding incompatible versions.
I have the exact same problem, running this command solves it:
go get -u -v github.com/mattn/go-sqlite3
Another tip: http://kokizzu.blogspot.co.id/2016/06/solution-for-golang-slow-compile.html
Using go1.6,
Simply run go build -i.
It will compile all the dependencies and store them at $GOPATH/pkg/*/* as .a files.
Later when you run go run main.go, everything is much faster.
What s really great is that if you use vendored dependencies (IE: a vendor folder in your project), deps are built appropriately within $GOPATH/pkg/**/yourproject/vendor/**
So you don t have to go get install/get/whatever and have a mix of vendor / global dependencies.
I suspect you got to re-build .a files after deps update (glide update or smthg like this), but i did not test that yet.
After Go 1.10, you'd just need to type go build. You'd not need to type: go build -i.
From the draft Go 1.10 document, here.
Build & Install
The go build command now detects out-of-date packages purely based on the content of source files, specified build flags, and metadata stored in the compiled packages. Modification times are no longer consulted or relevant. The old advice to add -a to force a rebuild in cases where the modification times were misleading for one reason or another (for example, changes in build flags) is no longer necessary: builds now always detect when packages must be rebuilt. (If you observe otherwise, please file a bug.)
...
The go build command now maintains a cache of recently built packages, separate from the installed packages in $GOROOT/pkg or $GOPATH/pkg. The effect of the cache should be to speed builds that do not explicitly install packages or when switching between different copies of source code (for example, when changing back and forth between different branches in a version control system). The old advice to add the -i flag for speed, as in go build -i or go test -i, is no longer necessary: builds run just as fast without -i. For more details, see go help cache.
I just experienced the same problem - updating from 1.4 to 1.5. It seems that the olds versions are somehow incompatible or are being rebuild every time as go build -x shows. Executing go get -v invalidates all packages or refetches them, I am not quite sure and go build -x shows quite less output.
You can build sqlite3 like this:
cd ./vendor/github.com/mattn/go-sqlite3/
go install
After that your project will b built much faster.
If you try as all other said but still not work, I suggest removing the directory of $GOPATH such as :
sudo rm -rf $GOPATH
cd yourproject
go get -d
go get -u -v github.com/mattn/go-sqlite3

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