Gradle Plugins Offline Resolution

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1

Hello, I am attempting to design a Gradle project with the following requirements:

  1. No internet access.
  2. No pre-existing Gradle cache
  3. A portable Maven repository containing all necessary plugins and dependencies.

I have been able to get external dependencies to resolve in an offline environment without a Gradle cache already, but plugin resolution fails and I haven’t found a solution despite multiple attempts.

As a simple example of what I’m shooting for, here is my build.gradle

plugins {
    id 'java'
    id "com.google.protobuf" version "0.8.6"
}
dependencies {
    compile "junit:junit:4.12"
}
repositories {
    maven {
        url "file://${project.projectDir}/mavenRepo"
    } 	
    jcenter()
}

And my settings.gradle:

pluginManagement {
    repositories {
        maven {
            url "file:mavenRepo"
        }
    gradlePluginPortal()
    }
}

The error I get is:

* Where:
Build file '/home/user/git/project/build.gradle' line: 6

* What went wrong:
Plugin [id: 'com.google.protobuf', version: '0.8.6'] was not found in any of the following sources:

- Gradle Core Plugins (plugin is not in 'org.gradle' namespace)
- Plugin Repositories (could not resolve plugin artifact 'com.google.protobuf:com.google.protobuf.gradle.plugin:0.8.6')
  Searched in the following repositories:
    maven(file:/home/user/git/project/mavenRepo/)
    Gradle Central Plugin Repository

There must be some step I’m missing here, or something I’ve got confused about dependencies and plugins. If anyone can offer help, I’d greatly appreciate it!