Bundle Erlang OTP in COTS product - erlang

We want to include RabbitMQ in our product, which further requires Erlang OTP. We don't want our customers to install Erlang before they install our product and want to find out ways to include Erlang in our own product installer.
What are some strategies to do this? We want to support Windows & Linux. At the moment my understanding is that there is no ZIP version of Erlang on Windows. So here's what i am thinking
Include Erlang OTP installer and kick it off when our product installer runs
Install Erlang OTP, zip the install dir and have our product installer unzip it on the customer's machine
. . . ?
Thanks for any advise.
Edited on 10/21
I figured it out. When erl.exe start it spins up a name resolver daemon process (epmd.exe) for distributed erlang. The location of this exe is hard coded in /otp/install/path/bin/erl.ini.
After copying the otp installation from C:\Program Files to a directory of my choosing, I had to update the erl.ini file to reflect the change in the path to the empd process. After that I uninstalled OTP from c:\Program Files and was able to start erlang from the directory where it was copied over.
Ranjit

Another option which is standard way for releases is using rebar. This bundles OTP and it is more cleaner approach than copying the installed windows binaries and change the erl.ini or change the erl script in linux.

Related

What files or directories of a release are the bare minimum to run a release?

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.

Where is erlang system configuration file(sys.config) is located when using homebrew install

In the Erlang config documentation, it says:
When starting Erlang in embedded mode, it is assumed that exactly one system configuration file is used, named sys.config. This file is to be located in $ROOT/releases/Vsn, where $ROOT is the Erlang/OTP root installation directory and Vsn is the release version.
But I cannot find this file on my MacBook.
I am using sudo find / -name 'sys.config' but still cannot find it.
Are you starting Erlang in embedded mode? No, you do not. The second thing sys.config is expected there so you have to provide it there. If you are using erlang in interactive mode you can provide config using -config parameter to erl command. Normally Erlang can start without sys.config only using application configs. Try find /usr/lib -name '*.app'. See env option there. I recommend you to read OTP Design Principles
User's Guide 8 Applications.

Windows x64 RabbitMQ install error with Erlang environment var (ERLANG_HOME)

I'm ask/answering this question because it hung me up & it's likely someone else will have the same problem.
Install of RabbitMQ x64 v2.8.6 on Windows Server 2008 x64.
After Erlang install using default install location to C:\Program Files\erl5.9.2, I'm attempting to start the server via running the rabbitmq-service.bat. Fail:
Please either set ERLANG_HOME to point to your Erlang installation
or place the RabbitMQ server distribution in the Erlang lib folder.
Problem is the .bat file does not have the correct subpath. with 5.9.2 (R15B02) version of erlang. My ERLANG_HOME directory is set correctly, but the script does not use it correctly for this version of Erlang, which, it appears to this Erlang noob to have a new subdirectory called "erts-5.9.2" which is causing the problems. Maybe someone intimate with these scripts can describe how to make this work correctly without the hack workaround I'm about to describe?
1- Set environment variable:
Variable name : ERLANG_HOME
Variable value: C:\Program Files (x86)\erl6.4
note: don't include bin on above step.
2- Add %ERLANG_HOME%\bin to the PATH environmental variable:
Variable name : PATH
Variable value: %ERLANG_HOME%\bin
This works well.
There are several RabbitMQ control .bat files on windows. Every one you use needs to get changed to reflect the Erlang path correctly. In this example, I'm editing the rabbitmq-server.bat because it's one of the easier ones... any of the .bat files you want to run will need this hack to get them to work, with the rabbitmq_service.bat file being the most involved to adjust.
editing that rabbitmq_server.bat file, you can see on about line 48 or so there's a check to see if the erl.exe is found, but the path isn't correct:
if not exist "!ERLANG_HOME!\bin\erl.exe" (
that path does not match the file structure for the 5.9.2 version of Erlang. I fixed this by simply removing this path check from about line 48 to 58, then, where the .bat actually makes a call to the erl.exe on about line 129 which reads:
"!ERLANG_HOME!\bin\erl.exe"
I simply hardcoded the path to my erl.exe:
"C:\Program Files\erl5.9.2\erts-5.9.2\bin\erl.exe"
With the pathing correct, the rabbitmq .bat files will run.
I had the similar issue, modifying ERLANG_HOME in .bat files did not work. Then I tried echo %ERLANG_HOME% in command prompt, that did not print the environment variable value(I could see that ERLANG_HOME environment variable has been created under advance system settings), that lead me to believe that I need to restart server for 64 bit installation of Erlang. After rebooting server, It worked like a charm. I hope this helps someone.
Just to share an up-to-date answer as of 2019: On Windows Server 2019, after setting up the environment variable, a restart is required to solve the problem.
I got into same kind of problem.
I solved it by doing three changes as given below.
Update Path variable "ERLANG_HOME" : "C:\Program Files\erl8.0" in Environment Variables.
Upadte "Path" variable "Path" : ";%ERLANG_HOME%\bin;"
Give urself FULL CONTROL permissions over "Program Files" in C drive.
It worked for me in this way.
This problem still occurs in Erlang 18.3 (erl7.3) and RabbitMQ 3.6.9 on Windows when upgrading from any older version of RabbitMQ to version 3.6.9. The solution as already stated here is to manually set ERLANG_HOME with 'setx -m ERLANG_HOME "C:\Program Files\erl7.3"' before starting the service.
What happens is that the RabbitMQ 3.6.9 installer removes the environment variable ERLANG_HOME from the system while removing the older version of RabbitMQ. Then, when it proceeds to the installation step, it does not put back the ERLANG_HOME variable. Then, the batch files that start up RabbitMQ cannot find Erlang. They try to find Erlang's home directory using "where.exe" but it always fails after an upgrade.
RabbitMQ's installer also does not kill all of the Erlang background processes, causing many of its files to be undeletable due to the Windows "file in use" problem. This leaves behind "files in use" in %APPDATA%\RabbitMQ and "C:\Program Files\RabbitMQ." These processes are "erl.exe," "erlsrv.exe," and "epmd.exe." The RabbitMQ installer should taskkill these processes after shutting down the RabbitMQ Windows service.
RabbitMQ is rather clunky on Windows.
Download Erlang or OTP - Only one Version of OTP should be installed
Download RabbitMQ installer
Install both exe file as Administrator
Set class path for Erlang. (Setting classpath is a bit troublesome, so follow these steps)
Set a new path with name ERLANG_HOME and value C:\Program Files\erl-23.1 (do not copy bin folder here)
Edit System "path" and add %ERLANG_HOME%\bin
Go to Start - Open rabbitmq command promt and run
rabbitmq-plugins enable rabbitmq_management
Navigate to localhost:15672
Use guest/guest to login
Interesting that this worked for you. There is record of a two bugs in Erl5.9.2 that cause an incomplete installation where %ERLANG_HOME%\bin is not installed.
Either of
* Installed 64bit erlang on 32bit machine
* "The program can't start because MSVCR100.dll is missing from your computer."
https://groups.google.com/d/topic/erlang-programming/wGtFLzapiQ0/discussion
Try 5.9.1 or any other version. They also mention making the future versions of the installer alert you if it fails.
I just had the same problem mentioned here. I installed otp_win64_R15B02 on a Windows 7 machine and everything worked perfectly, but I used the same installer on a Windows 2008 server and the bin directory was not created. I then uninstalled otp_win64_R15B02 and downloaded the otp_win64_R15B02_with_MSVCR100_installer_fix and the bin directory was created.
I suspect the reason it worked on my Windows 7 system is that I have Visual Studio installed and the required libraries were already available which allowed the otp_win64_R15B02 installer to work correctly.
Oh, and if you're installing Erlang to run RabbitMQ the RabbitMQ install will succeed with the broken installer but installing otp_win64_R15B02_with_MSVCR100_installer_fix after RabbitMQ will not work, just un-install and re-install RabbitMQ to resolve this.
Just give C:\Program Files\erl10.6\ not C:\Program Files\erl10.6\bin\erl.exe in the environment variable. If you open the server.bat file I came to know the issueenter image description here
I think this is encoding issue on windows.I see a correct value but I write echo %ERLANG_HOME% on console the value come with question mark. These steps fix it.
1.go environment variable window
2.edit ERLANG_HOME item
3.copy the value, open notepad and paste there
4.copy again on notepad and paste to edit window
5.apply and exit window
6.close command line tools and reopen
7.run rabbitmq bat file.
I solved it in a quick and dirty way,without naming path variables
I've opened the bat file and replaced every occurrence of
!ERLANG_HOME!\bin\erl.exe
with hard coded path for example might be diffrent path for you because of diffrent version
C:\Program Files\erl10.3\erts-10.3\bin\erl.exe
and replaced
%RABBITMQ_HOME%\escript\rabbitmq-plugins
with
C:\Program Files\RabbitMQ Server\rabbitmq_server-3.7.14\escript\rabbitmq-plugins
Even I was this problem. The issue was the environment variable ERLANG_HOME=c:\Program Files\erl9.0 which was never existed.
I cross checked the path. The correct path was c:\Program Files\erl9.3.
After correcting the
ERLANG_HOME=c:\Program Files\erl9.3
the problem solved. So, definitely it is a path issue.
In my case, it should be installed erlang using admin role running
If above solutions doesn't work for you then you can try following
Find another compatible version of erlang for your rabbit mq e.g. for rabbit 3.7.x erlang version 20.3.x to 22.0.x all are compatible .
Right click newly downloaded erlang version and from properties select the option to unblock the file .
Run the erlang with admin persssion .
Re run rabbit mq exe

Can i run Erlang without local admin rights on Windows?

I have a machine which doesn't give me local admin rights. Is it still possible to run erlang on it, as I cannot run a windows .exe installer to install erlang?
You can copy erl.exe (plus the runtime system and all the libraries you need) from another installation and run it without the need to install. As long as you are allowed to execute files it should be okay.
Forgive me for not being as smart as Zubair,
but I would like to know exactly how to do this.
I do not have admin privilege, cannot run installers, and cannot copy files to C:\WINDOWS.
In particular, I cannot write to C:\WINDOWS\WinSxS or C:\WINDOWS\system32.
How do I get a list of exactly what libraries are required by the various erlang executables ?
I have all the MS redistributable libraries and manifests,
but I don't know where to put them to make it work.
The redistributable library structure has directories such as
Microsoft.VC90.ATL, Microsoft.VC90.CRT, etc. Each directory contains relevant dlls and a manifest.
Do I copy all the contents into the ERL_HOME\bin directory or ERL_HOME\erts-x.y.z\bin or ERL_HOME\erts-x.y.z\lib ?
or leave them in some other directory and put those entries in the PATH ?
or do I need to build the paths implied by the manifests (i.e. where they would be copied into the WinSxS cache) using hashes and version numbers in the paths, then put those entries in the PATH ?

What do you use if you wish to install an Erlang library?

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.

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