upload_custom_android_app.rb

require "google/apis/playcustomapp_v1"

# Auth Info
KEYFILE = "KEYFILE.json" # PATH TO JSON KEYFILE
DEVELOPER_ACCOUNT = "DEVELOPER_ACCOUNT_ID" # DEVELOPER ACCOUNT ID

# App Info
APK_PATH = "FILE_NAME.apk" # PATH TO SIGNED APK WITH V1+V2 SIGNATURES
APP_TITLE = "APP TITLE"
LANGUAGE_CODE = "EN_US"

scope = "https://www.googleapis.com/auth/androidpublisher"
credentials = JSON.parse(File.open(KEYFILE, "rb").read)
authorization = Signet::OAuth2::Client.new(
 :token_credential_uri => "https://oauth2.googleapis.com/token",
 :audience => "https://oauth2.googleapis.com/token",
 :scope => scope,
 :issuer => credentials["client_id"],
 :signing_key => OpenSSL::PKey::RSA.new(credentials["private_key"], nil),
)
authorization.fetch_access_token!

custom_app = Google::Apis::PlaycustomappV1::CustomApp.new title: APP_TITLE, language_code: LANGUAGE_CODE
play_custom_apps = Google::Apis::PlaycustomappV1::PlaycustomappService.new
play_custom_apps.authorization = authorization

play_custom_apps.create_account_custom_app(
 DEVELOPER_ACCOUNT,
 custom_app,
 upload_source: APK_PATH,
) do |created_app, error|
 unless error.nil?
   puts "Error: #{error}"
 else
   puts "Success: #{created_app}."
 end
end