Packaging and Distributing Flutter Desktop Apps : The Missing Guide for Open Source & Indie Developers — Creating Linux Debian (.deb) & RPM (.rpm) builds [Part 3 of 3]

by Ashita Prasad (LinkedIn, Twitter), fluttergems.dev

Articles in this series:

• Introduction & creating macOS .app & .dmg — Part 1 of 3
• Creating Windows .exe installer — Part 2 of 3
• Creating Linux Debian (.deb) & RPM (.rpm) builds — Part 3 of 3 [This article]

In the previous articles of this series, we uncovered the motivation behind creating this step-by-step guide for packaging and distributing Flutter desktop apps the “indie” way or the open source way. We covered the entire process we follow (step-by-step) to build the macOS distribution (.dmg) & the Windows installer (.exe) of API Dash, an open source alternative to Postman that we have built completely using Flutter (GitHub repo👇).

API Dash running on Linux

GitHub — foss42/apidash: API Dash is a beautiful open-source cross-platform API Client built using…

In this article, we will go through the step-by-step process of creating Linux distributions (both .deb & .rpm) of your Flutter desktop app.

Packaging & Publishing Flutter Desktop App for Linux

To learn how to build & publish Linux app on Snap Store check out the official docs on integration & deployment.

In the Linux ecosystem, .deb (Debian) & .rpm (Red Hat Package Manager) are the two most widely used formats for software distribution. Based on the Linux distro, the end-user can choose the right package to install the Flutter application:

• .deb bundle is used to install an app in any Debian linux distribution like Debian, Ubuntu, Linux mint, etc.
• Whereas, .rpm bundle is used to install a desktop app in any Red Hat linux distribution like Red Hat Linux, Fedora, Rocky, etc.

Based on the CPU architecture of the system which is being used to create the build, the corresponding target builds are created:

• Apple Silicon or ARM based to create arm64/aarch64 bundles.
• Intel 64 bit to create amd64/x86_64 bundles.

Pre-requisites

You can either use a Linux machine or a Linux distro running on a VM to create linux builds of your Flutter desktop app.

Linux Distros running on A VM

Debian based distro (like Ubuntu) should be the preferred as you can build both .deb & .rpm builds in the same system. This is possible due to rpmbuild & patchlf libraries which can be installed using the following command in Ubuntu/Debian:

apt install rpm patchelf

To compile Flutter desktop app in Linux you would also need to install the following tools:

• Clang
• CMake
• git
• GTK development headers
• Ninja build
• pkg-config
• liblzma-dev
• libstdc++-12-dev

These tools can be installed by running the following command in the terminal:

sudo apt-get install clang cmake git ninja-build pkg-config libgtk-3-dev liblzma-dev libstdc++-12-dev

Your build can break, in case any of the above tools are missing.

Creating a Debian (.deb) Bundle

Step 1

Now, let us start with the process of creating the builds.

We will use the flutter_distributor tool to create the Linux packages/bundles of our Flutter desktop app.

flutter_distributor | Dart Package

It can be easily installed and activated using the following command:

dart pub global activate flutter_distributor

Step 2

Create distribute_options.yaml file in your project root directory. The config file is used to provide the specifications for various builds like for different target platforms or for different environments like development, QA or production.

distribute_options.yaml

Let us create a release specification for our debian build. The contents of the distribute_options.yaml file is provided below:

output: dist/
releases:
  - name: dev
    jobs:
      - name: release-dev-linux-deb
        package:
          platform: linux
          target: deb
          build_args:
            enable-experiment: records

The name of the release is specified as dev and inside it there can be multiple jobs, like to build for linux, android, ios, etc.

We created a single job with name release-dev-linux-deb where we specified our platform and target as linux & deb. Additional command line arguments or compile time constants can also be specified via build_args like in this case we provided records value to the enable-experiment flag to indicate that the experimental Dart records feature is being used.

Step 3

Create a new directory named packaging inside the linux folder in the project home. This folder will contain the config files used for our linux builds.

As we want to create a debian build, create a new folder named deb inside the packaging folder.

Now, create make_config.yaml inside this folder. This file will be used to specify the details to build the debian bundle.

The final path of this file is:

/path/to/project/linux/packaging/deb/make_config.yaml

In make_config.yaml, we can specify all details that are required to create the .deb build like:

• The display name for the application
• The name of the package (lowercase, nospace — actual name which can be executed via terminal)
• Maintainer information
• App icon path
• Metadata such as app category & keywords
• External dependencies
• Other required information used for creating the build.

A sample make_config.yaml spec is provided below:

display_name: API Dash
package_name: apidash

maintainer:
  name: Ashita Prasad
  email: ashita@xyz.com

priority: optional

section: x11

installed_size: 15700

dependencies:
  - mpv

essential: false

icon: linux/assets/apidash.png

postuninstall_scripts:
  - echo "Sorry to see you go."

keywords:
  - API
  - API Client

generic_name: API Client

categories:
  - Development
  - Utility

startup_notify: true

Step 4

Your Flutter app might be using packages that have external dependencies that must be specified in the make_config.yaml file as shown below:

These dependencies need to be installed on the end users system in order to use the application. To figure out these dependencies, check the pub dev page of packages that have been used in the project. Developers usually specify the dependencies in the readme file.

For example, flutter_secure_storage has the following external dependencies required to run the app using it:

• libsecret-1-0
• libjsoncpp1

Linux dependencies for flutter_secure_storage

In case only debian dependencies are mentioned and you also want the corresponding rpm dependencies, you can check out pkgs.org to find their rpm equivalent.

Step 5

Run the following flutter_distributor command to generate the build.

flutter_distributor release --name=dev --jobs=release-dev-linux-deb

deb package build in progress

Step 6

Once the build is successfully completed, the location of the bundle will be displayed.

deb build ready for distribution

To distribute the bundle via GitHub, you can create a new release and attach the .deb file as shown below.

Once the release is published, the deb bundle will be available for download to all users. It can be installed using the following commands:

sudo dpkg -i app.deb

or

sudo apt install ./app.deb

Creating a RPM (.rpm) Bundle

To create a RPM build of your Flutter desktop app for Red Hat-based Linux Distributions (Fedora, Rocky, AlmaLinux, CentOS, RHEL, etc.), the steps are exactly same as for the debian build provided above with slight differences in the steps mentioned below:

Step 1

Same as for .deb

Step 2

Modify the distribute_options.yaml file in your project root directory to add a new job release-dev-linux-rpm to target rpm.

output: dist/
releases:
  - name: dev
    jobs:
      - name: release-dev-linux-deb
        package:
          platform: linux
          target: deb
          build_args:
            enable-experiment: records
      - name: release-dev-linux-rpm
        package:
          platform: linux
          target: rpm
          build_args:
            enable-experiment: records

Step 3

Create a new folder named rpm inside the linux/packaging folder.

Now, create make_config.yaml inside this folder. This file will be used to specify the details to build the RPM package.

The final path of this file is:

/path/to/project/linux/packaging/rpm/make_config.yaml

In make_config.yaml, we can specify all details that are required to create the .rpm build like:

• The display name for the application
• App icon path
• Application description
• Maintainer information
• License
• Metadata such as app category & keywords
• External dependencies (requires)
• Other required information used for creating the build.

A sample make_config.yaml spec for RPM build is provided below:

display_name: API Dash
icon: linux/assets/apidash.png
summary: A beautiful lightweight open-source cross-platform API Client
group: Applications/Development Tools
vendor: Ashita Prasad
packager: Ashita Prasad
packagerEmail: ashita@xyz.com
license: ASL 2.0
url: https://github.com/foss42/apidash

build_arch: aarch64

requires:
  - mpv

keywords:
  - API
  - API Client

generic_name: API Client

categories:
  - Development
  - Utility

startup_notify: true

Note: The external dependencies are provided under requires and the process is same as described in Step 4 for debian build.

Step 5

Run the following flutter_distributor command to generate the RPM build.

flutter_distributor release --name=dev --jobs=release-dev-linux-rpm

Step 6

Once the build is successfully completed, the location of the bundle will be displayed.

To distribute the bundle via GitHub, you can create a new release and attach the .rpm file as shown below.

Once the release is published, the rpm package will be available for download to all users. It can be installed using the following commands:

sudo dnf localinstall ./app.rpm

or

sudo rpm -i app.rpm

or

sudo yum localinstall ./app.rpm

Closing Notes

In this article, we learnt how to create a Debian (.deb) and RPM (.rpm) distribution for a Flutter desktop app the “indie” or open source way. You can check out the other article in this series to learn how to do the same for other desktop platforms.

• Introduction & creating macOS .app & .dmg — Part 1 of 3
• Creating Windows .exe installer — Part 2 of 3

In case you have any doubts or queries please feel free to comment below or drop in our Discord Server.

This article is brought to you by Flutter Gems, a curated list of top Dart and Flutter packages that are categorized based on functionality. Do check it out below 👇

Flutter Gems - A Curated List of Top Dart and Flutter packages