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Creating Component: AppImage

Appimage logo

This a part of the How-to: Create Components Guide

We are going to use CEMU as an example and remember that each AppImage is different from another.

Note:

This assumes you have read Creating Component: Guide.

Step 0: Make a testing directory

  1. Have a local copy of RetroDECK Cooker installed.
  2. Create a components directory for example: ~/retrodeck_dev/components/

Step 1: Download the AppImage from Source

  1. Download the file from Github/Website or where every you find it.
  2. Put it into retrodeck_dev/components/.
  3. Create a directory in retrodeck_dev/components/<component_name> that matches the name of the component you want to add.

Example:

wget "https://github.com/cemu-project/Cemu/releases/download/v2.6/Cemu-2.6-x86_64.AppImage"
  1. Put it into retrodeck_dev/components/Cemu-2.6-x86_64.AppImage.
  2. Create a directory called retrodeck_dev/components/cemu.

Step 2: Permissions & Extract

Open a terminal window in retrodeck_dev/components/

Set Permissions:

chmod +x "XXX.AppImage"

Extract it:

./XXX.AppImage --appimage-extract

Example:

chmod +x "Cemu-2.6-x86_64.AppImage"`
./Cemu-2.6-x86_64.AppImage --appimage-extract

Step 3: New directory and move.

A new directory called retrodeck_dev/components/squashfs-root has been created.

The structure is different in each AppImage.

AppRun exists in every AppImage and it can be either a:

  • Script (that launches the binary).
  • Binary (separate but launches the main binary).
  • Symlink (to the main binary).

Other standard files such as: icons, .desktop also exist in every AppImage.

Most follow these structures (with additional directorys and files depending on the app):

AppImage V2:

- squashfs-root
    - AppRun (a script, binary or symlink)
    - usr
        - bin (contains the binary)
        - lib   
        - share

AppImage V3:

squashfs-root (links to AppDir)
AppDir 
    - bin (contains the binary)
    - lib   
    - share

Examples of AppImage Structures

Cemu

squashfs-root
    - AppRun
    - apprun-hooks
    - checkrt
    - usr
        - bin (contains the binary)
        - lib   
        - share

Eden

squashfs-root (links to AppDir)
AppDir
    - bin (contains the binary)
    - lib (link) 
    - etc 
    - share
    - shared

Azahar

squashfs-root
    - AppRun 
    - apprun-hooks
    - checkrt
    - usr
        - bin (contains the binary)
        - lib   
        - share
        - plugins
        - translations

Mudlet

squashfs-root (contains the binary)
    - AppRun 
    - <translation files>
    - doc (licences)
    - lcf
    - lib
    - mudlet (binary)
    - mudlet-lua
    - plugins
    - translations

ES-DE:

squashfs-root
    - AppRun (a script, binary or symlink)
    - usr
        - bin (contains the binary)
        - lib   
        - share

OpenGOAL:

squashfs-root
    - AppRun
    - apprun-hooks
    - checkrt
    - usr
        - bin (contains the binary)
        - lib   
        - share

Step 5: Testing

During this step, identify and document the following:

  • Binary
  • Dependencies
  • Libraries
  • Other important files

Testing Procedure

  1. Launch the binary from the RetroDECK Flatpak shell: flatpak run --command=bash net.retrodeck.retrodeck --debug
  2. Launch the application normally within your host OS environment (outside RetroDECK).
  3. Document the results in detail.

While testing, record:

  • Fully functional features
  • Partially functional features
  • Non-functional components
  • Errors, warnings, crashes, or unexpected behavior

Issue resolution will be handled later during the Alchemist and Hunter step.

Example Considerations

  • Are all expected features functioning correctly?
  • Does the application create directories or files in user locations (~/Documents, ~/.local, ~/.config, ~/, or other paths)?
  • Does the application report any missing libraries or dependencies, both outside and inside the Flatpak environment?
  • Does it crash at startup or during normal operation, both outside and inside the Flatpak environment?

Step 6: Creating Component: Ingredient Files

You now will need to move on to the next step:

Read more here: Creating Component: Ingredient Files Guide