Someone once showed my an open source tool for downloading building and managing multiple Erlang SDK's on a single machine but I can't for the life of me remember what it was called?
Are you thinking about kerl?
First you'd build a release:
kerl build 18.0 my-18.0
And then install it:
kerl install my-18.0 ~/erl-18.0/
To use it, either run the programs in ~/erl-18.0/bin directly, or source ~/erl-18.0/activate to add that directory to PATH:
source ~/erl-18.0/activate
Related
Let's say, I have a completely new VPS server which I've just rolled out, which I haven't installed anything on yet.
And I've compiled and build a production release of Phoenix application on my local machine which is identical to a VPS server Linux distributive- and version-wise.
In the directory _build/prod/rel/my_app123 there have been generated 4 subdirectories:
bin
erts-12.3
lib
releases
Will copying the content of rel/my_app123/, that is, these 4 subdirectories, over to a VPS will be absolutely enough in order to run an application?
Or will I have install something extra as well? Elixir and Erlang?
How about production dependencies from mix.exs? Or are these have been included and compiled into into a release?
P.S. Assume that my web application has no "js", "css" and the like files, and doesn't use a database.
When you run mix release, it bundles all of your Elixir/Erlang dependencies for the MIX_ENV in question into the release directory, the erlang BEAM runtime/VM that you were using in your build, and any files that you specify in your mix project in mix.exs.
Because the BEAM runtime and code that bootstraps loading your code are included in the release, you won't need to install Elixir or Erlang on the target machine.
Things that are not included include:
any non-Elixir dependencies. For example, if you rely on openssl, you'll need to make sure you have a binary-compatible version of that installed on the machine you plan to run on (typically, the equivalent major verson release).
Portable bytecode. BEAM isn't like the Java VM. The compiled BEAM code needs to run on a substantially similar architecture. Build on an Arm64 machine for deployment on an Arm64 virtual machine, or x86 for Intel-compatible hardware, for instance. And it's probably best to use the same major OS distribution. There may be cases where "Any Linux * Same CPU architecture" is fine, but for example, building on a Windows or MacOS install of Elixir/OTP and deploying on Linux is a non-starter; you'd need to use a sufficiently similar OS.
As an example, one of my projects has its releases built on Alpine using Docker, so we only really have to worry about CPU compatibility. In our case we do need to make sure some external non-Elixir dependencies our app binds to are included on the docker image.
RUN apk add --no-cache libstdc++ openssl ncurses-libs wkhtmltopdf xvfb \
fontconfig \
freetype \
ttf-dejavu
(ignore the fact that wkhtmltopdf is kind of deprecated, we're working on it. But for now it's a non-elixir dependency we rely on).
If you're building for a, say, an EC2 instance and not using Docker, you'd just need to make sure your release is built on a similar OS to what you're using for production, and make sure the production AMI (image) has those non-Elixir dependencies on it, or will at the time of deployment, perhaps using apt or another package manager. For a VPS, the solution for non-elixir dependencies will depend on whether they have the option for customizing the base machine image (maybe with Packer or Ansible)
Since you may seem to have been a bit confused about it in the comments, yes, MIX_ENV=prod mix release will build all of your production Elixir/Erlang dependencies and include them in the /_build/prod folder.
I include the whole ./prod folder in our release, but it looks like protocol consolidation binaries and the lib folder .Beam files are all in the rel folder so that's a bit unnecessary.
If you do a default build, the target will be inside your _build directory, with sub-directories for the config environment and your application, e.g. _build/dev/rel/your_app/. That directory should contain everything you need to run your app -- the prompt after running mix release provides some clues for this when it says something like:
Release created at _build/dev/rel/your_app!
I find it more useful, however, to zip up the app into a single portable file (and yes, I agree that the details about how to do this are not necessarily the first things you see when reading about Elixir releases). The trick is to customize your mix.exs by fleshing out the releases option -- this is usually done via a dedicated private function but the organization of how you supply the options is up to you.
What I find is often useful is the generation of a single zipped .tar.gz file. This can be accomplished by specifying the include_executables_for option along with steps. It looks something like this:
# mix.exs
defmodule YourApp.MixProject do
use Mix.Project
def project do
[
# ...
releases: releases()
# ...
]
end
defp releases do
[
my_app: [
include_executables_for: [:unix],
steps: [:assemble, :tar]
]
]
end
When you configure your application this way, running mix release will generate a nice portable file containing your app with everything it needs. Unzipping this file is education for understanding everything your app needs. By default this file will be created at a location like _build/dev/yourapp-1.0.0.tar.gz. You can configure the build path by specifying a path for your app. See Mix.Release for more options.
I revised some source code of OpenCV's legacy module. My project is coded based on the new legacy module and I want to debugging it. One way that I can think out is using my revised legacy source code to replace the original legacy module, then compile and reinstall the whole OpenCV. I think this way is too waste of time and other modules(e.g. imgproc, highgui, etc) haven't any change and don't need to be reinstalled. I think there must have an easier way to solve it.
My developing environment is VIM && GDB && opencv 2.4.13. I am a green-hand of linux-opencv. How do I build OpenCV's single module in Ubuntu? If I want keep the original legacy module and the new legacy module in case of other usage, how should I do?
There is a way to actually build a single module without building the entire source from the beginning. I guess you would have followed this procedures to install OpenCV in your machine OpenCV Installation in Linux.
After the modifications in OpenCV's legacy module, you can build just that module by using the commands.
# Go to the build directory. If you followed the tutorial I shared then it is the release folder
cd release
# And build only the module you want to (For example, legacy model as in your case)
make opencv_legacy
sudo make install
I am working on a project that is transitioning from CMake to Bazel. One critical feature that we are apparently losing in the bargain is the ability to install the project, so that it can be used by other (not necessarily Bazel) projects.
AFAICT, there is currently no built in support for installing a project?!
I need to create a portable (must work on at least Linux and MacOS) way to install the project. Specifically:
I need to be able to specify libraries, headers, executables, and other files (e.g. LICENSE) that need to be installed.
The user needs to be able to specify an absolute prefix where things should be installed.
I really, really should be able to execute the "install" step more than once, giving different prefixes each time, without Bazel getting confused (i.e. it must not try to "remember" what files it already installed, or if it does, must understand when the prefix is different from last time).
Libraries should be installed to the right place (e.g. lib64), or at least it should be possible for the user to specify the correct libdir.
The install step MUST NOT touch the time stamp on any file from a previous install that has not changed. (Ideally, Bazel itself would handle this; using the install command is tricky and has potential portability issues. Note platform requirements, above.)
What is the best way to go about doing this?
Unless you want to do specific package (e.g. deb or rpm), you probably want to create an executable rule that does the install for you.
You can create a rule that would create an executable (e.g. a shell script) that does the install for you (e.g. do checksums to check if there are change to the installed file and does the actual copy of the files if they have changed). You would have to use the extension language to do, that would look similar to what the docker rules does to load an image with the incremental loader
Addition: I forgot to say that the install itself would be run by using the run command: bazel run install if the rule is named install in the top level BUILD file.
I'm trying to run pub deploy command in my Dart project, but it always ends with this error: "Pub deploy failed, [1] Cannot read link". No more information outputs into console.
I tried to run it in basic Dart browser project (the one with text reversing), but same error occurred again.
Did anyone have same problem? Any ideas how to fix it?
I have the same issue.
In my case, the Dart project is stored in NTFS hard drive (I share it with Windows OS) and Dart deploy (run from Eclipse) runs on Ubuntu.
Simply move the Dart project to Ubuntu hard drive then things come back to normal.
GS
This is probably a problem with the packages symlinks. If you delete them and run pub install it should work again.
According to dart-sdk/lib/io/link.dart:
On the Windows platform, the link will be created as a Junction
On other platforms, the posix symlink() call is used to make a symbolic link
On Linux platforms, storing Dart project in NTFS drive causes Pub to fail. Because posix symlink() is used on NTFS partition and doesn't create a valid NTFS junction point.
The solution is to move the project folder to a partition that uses posix symlinks natively, such as one formatted to ext4.
Do you use CEAN, copy the source and compile them, copy the BEAM files, or something else. I need to distribute some Erlang code and I'm not sure which to choose.
I've been working on EPM, an Erlang package manager. It pulls from GitHub. It's non-invasive and doesn't require installing anything on your system other than downloading an escript. It works as follows:
jvorreuter$ ./epm install ibrowse mochiweb
epm v0.1.0, 2010
===============================
Install the following packages?
===============================
+ epm-mochiweb-master
+ cmullaparthi-ibrowse-master
([y]/n) y
+ downloading http://github.com/epm/mochiweb/tarball/master
+ running mochiweb build command
+ running mochiweb install command
+ downloading http://github.com/cmullaparthi/ibrowse/tarball/master
+ running ibrowse build command
+ running ibrowse install command
You can read more about it at http://www.jkvor.com/erlang-package-manager
The linked blog post is blank as of August 2013. The GitHub repository is at https://github.com/JacobVorreuter/epm
I clone the git repository, build it, and add the directory to my ERL_LIBS path. I hack the source for my private customizations. For those commits that are sensible, I publish.
I am a much happier developer after finding git and being able to manage my own changes and still be able to get upstream changes that I can rebase my stuff on.
I realize that this looks raw for end users, but I am my own end user.
If I would ship something to other end users I would look into using .ez zip archive files that the erlang code loader can use. See section "Loading of Code From Archive Files" on that page. Then provide a script that invokes erl with the correct arguments.
If the repository isn't available as a git, I git-svn clone it. If I can't do that, I tend to stay away from it.
I use faxien (a package manager for Erlang releases and applications) from the Erlware project: http://www.erlware.org. It and sinan are essential tools for Erlang development :).
I use Agner on Mac, Linux, and Unix; and CEAN on Windows. CEAN's the only Erlang package manager with Windows support.
I package them on a Debian repository on Launchpad.