Maven: non lifecycle-related goal - maven

I have project for which you need to have a few dependency downloadable from an internal repo.
If this is not possible I'd like to provide an option to install the deps locally (using maven-install-plugin).
Point is: since this is fully optional I do not want this to be part of the regular lifecycle (I've seen solutions where the install plugin is executed in the clean phase). Which is the terser and more elegant way to provide an option to install prerequisites locally?

Related

Can I split dependency resolution in maven into separate command?

I want to split a mvn install command into 2 separate ones - dependency resolution and build itself, like it can be done in NPM (with npm run ci and npm run webpack separately). The reason to do so is to measure how much time is spend on dependency resolution and how much on build itself.
I have tried to use mvn dependency:go-offline with mvn install -o afterwards. According to docs this is exactly what I need, however it does not work. Plugin dependencies are not downloaded (mentioned in pom file under build/plugins).
Can this goal be achieved somehow?
Indeed, it seems the dependency:go-offline standard goal is not "perfect" as some plugins may still trigger some (re)downloading during the mvn package phase.
(I had noticed this when looking at this SO question about how to optimally rely on Docker's cache.)
To fix this, you can try mvn de.qaware.maven:go-offline-maven-plugin:resolve-dependencies after installing the corresponding plugin mentioned in this SO answer by #user2813807.

Setting up Go environment for creating custom Terraform providers

I am getting a stuck while trying to create a Terraform provider. I have been following the advice given on https://www.terraform.io/docs/extend/writing-custom-providers.html but when I go to build my binaries via Go go build -o terraform-provider-example I get several missing packages errors.
So I then work my way down the list of missing packages and use go get ... to get those packages installed in my Go libraries.
I get an error indicating that github.com/hashicorp/hcl/v2 cannot be found. I navigate to the location and sure enough it doesn't exist.
Package not available at install time screen shot
Package not available with go get
So I am getting stuck and unable to build these providers. I have looked for a while now trying to find something which describes how to setup the environment for creating providers but have been unsuccessful so far. Can anyone help get me going?
Terraform Core and Terraform provider development requires using the Go toolchain in the new "modules mode", which in current versions of Go is not the default.
The easiest way to ensure you're working in modules mode is to clone the repository you want to work on outside the $GOPATH/src directory. Development outside of GOPATH is only supported in Modules mode, and so the Go toolchain assumes that you intend to use modules mode if you are working in that way.
One reason why Terraform development requires modules mode (though not the only one) is that it has a dependency on github.com/hashicorp/hcl/v2, which is a module path type that is not supported in the old GOPATH mode because previously the Go toolchain was only able to install from the master branch of a particular remote dependency in a Git repository. The module path github.com/hashicorp/hcl/v2 is the Go Modules way to specify using the second major version of HCL, whereas github.com/hashicorp/hcl is the first major version.
In modules mode, it should be sufficient to just run go build -o terraform-provider-example (or, if you prefer, go install) and it will automatically fetch the dependencies to the local modules cache and use them from there. In modules mode, go get is for changing the dependencies recorded in go.mod rather than for installing existing dependencies.

Fast way to rebuild and reload opendaylight bundle

I am developing a bundle for opendaylight. Is there a quick way to just rebuild the bundle without the complete karaf environment?
Thanks in advance!
Max
You can rebuild the bundle, without anything else, by running Maven in the directory containing your bundle’s POM. If you’re on the command-line:
cd your-bundle-directory
mvn compile
(or mvn install etc. depending on what you want to do exactly).

Advice on vendoring dependencies in Go

I am working on a project that requires some dependencies. I am a little confused by the best practices regarding vendoring. Currently I am using GO15VENDOREXPERIMENT and have copied the dependencies into the vendor directory.
https://github.com/jeffellin/machine-cloudformation/tree/master/vendor/github.com
When I need to update the dependencies I checkout the source code manually from docker-machine and copy it into my vendor directory. This brings in a lot of unnecessary code, tests, etc. Is there any recommendations on automating this? I am used to maven where I can just specify version info in a configuration file.
What about GODEPS? How does that play into the GO15VENDOREXPERIMENT. I would prefer a solution where I don't have to checkin dependencies into my source tree.
There are a few tools that help with vendoring your dependencies. Most of them are able to handle GO15VENDOREXPERIMENT.
For example:
godep
glide

Packaging Go application for Debian

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?

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