Building from Source¶

This guide covers building Mycel from source code for developers.

Requirements¶

System Requirements¶

Requirement	Version
JDK	17 (required)
Android SDK	API 36 (compile)
Gradle	8.x (wrapper included)

Recommended Setup¶

IDE: Android Studio Ladybug or newer
OS: macOS, Linux, or Windows with WSL

Build Configuration¶

SDK Versions¶

Configuration	Value
`compileSdk`	36
`minSdk`	26 (Android 8.0)
`targetSdk`	34 (Android 14)

Key Dependencies¶

Dependency	Version
Kotlin	2.1.0
Android Gradle Plugin	8.10.0
Hilt	2.57.2
Room	2.8.3
Compose BOM	2024.06.00

Getting the Source¶

git clone https://github.com/ethene/mycel.git
cd mycel

Building¶

Set Java 17¶

Ensure JDK 17 is available:

# macOS with Homebrew
brew install openjdk@17
export JAVA_HOME=$(/usr/libexec/java_home -v 17)

# Verify
java -version
# Should show: openjdk version "17.x.x"

Debug Build¶

./gradlew assembleDebug

The APK will be at: app/build/outputs/apk/debug/app-debug.apk

Release Build¶

Release builds require signing configuration. Create app/signing.properties:

storeFile=path/to/keystore.jks
storePassword=your_password
keyAlias=your_alias
keyPassword=your_key_password

Then build:

./gradlew assembleRelease

Installing¶

Using ADB¶

adb install app/build/outputs/apk/debug/app-debug.apk

Using Build Script¶

The project includes a build-and-install script:

./tools/build/rebuild_install_run_autodetect.sh

This script: 1. Detects connected devices 2. Builds the debug APK 3. Installs on all devices 4. Starts the app 5. Sets up port forwarding for debugging

Module Structure¶

mycel/
├── app/                    # Main application module
├── core/
│   ├── dtn/               # DTN protocol, bundles
│   ├── nearby/            # Nearby Connections transport
│   ├── ble/               # BLE transport
│   ├── transport/         # Transport abstraction
│   └── capabilities/      # Device feature detection
├── feature/
│   └── ui/                # Jetpack Compose UI
└── tools/                 # Development utilities

Testing¶

Unit Tests¶

# All tests
./gradlew test

# Specific module
./gradlew :core:nearby:test
./gradlew :core:dtn:test

Instrumented Tests¶

./gradlew connectedAndroidTest

Development Tools¶

Developer Bridge¶

The app includes a JSON-RPC bridge for debugging. After installation:

# Set up port forwarding
adb forward tcp:8875 tcp:8765

# Check status
curl -X POST -H 'Content-Type: application/json' \
  -d '{"method":"mesh.service.status"}' \
  http://localhost:8875/

meshctl CLI¶

The meshctl tool provides command-line access to the bridge:

./tools/bridge/meshctl.py --serial DEVICE_SERIAL status
./tools/bridge/meshctl.py --serial DEVICE_SERIAL nearby diag

Common Issues¶

"JDK 17 required"¶

Set JAVA_HOME to a JDK 17 installation:

export JAVA_HOME=/path/to/jdk17

"SDK not found"¶

Ensure ANDROID_HOME or ANDROID_SDK_ROOT is set:

export ANDROID_HOME=~/Android/Sdk

Gradle Daemon Issues¶

Clear the Gradle cache if builds fail unexpectedly:

./gradlew --stop
rm -rf ~/.gradle/caches/

Version Management¶

The app version is controlled by a single file:

app/src/main/assets/version.txt

The build system reads this file and generates: - versionName for display - versionCode for Play Store (if ever published)

Release Process¶

Releases are managed via GitHub:

Update version.txt
Run ./tools/release/prepare_release.sh
CI builds and publishes the APK to GitHub Releases

Contributing¶

Fork the repository
Create a feature branch
Make changes
Run tests: ./gradlew test
Submit a pull request

See also: Architecture Overview | Message Flow