Is appengine-tools-sdk (used in this repo) closed source?

[aubreyyan]

I've been trying to track down the source code behind what is powering the endpoints-framework-maven-plugin and so far I've managed to track it down from

    <dependency>
      <groupId>com.google.endpoints</groupId>
      <artifactId>endpoints-framework-tools</artifactId>
      <version>2.2.0</version>
    </dependency>

which is imported from endpoints-java which in turn gradle builds from whatever is

endpoints-java/endpoints-framework-tools/build.gradle

Line 34 in 39b7374

compile group: 'com.google.appengine', name: 'appengine-tools-sdk', version: appengineVersion

which I've managed to track down to this dependency in mvnrepository.

I can't find a repository for it on github and when I try to Download Sources via IntelliJ I get an error I've never seen before.

11:57:04 PM: Executing task 'DownloadSources'...

> Task :endpoints-framework-tools:DownloadSources FAILED

FAILURE: Build failed with an exception.

* Where:
Initialization script 'C:\Users\aubre\AppData\Local\Temp\ijmiscinit2.gradle' line: 20

* What went wrong:
Execution failed for task ':endpoints-framework-tools:DownloadSources'.
> Could not resolve all files for configuration ':endpoints-framework-tools:downloadSources_d7b2fb13-d1c7-411c-8365-a776db2352d0'.
   > Could not find appengine-tools-sdk-sources.jar (com.google.appengine:appengine-tools-sdk:1.9.60).
     Searched in the following locations:
         file:/C:/Users/aubre/.m2/repository/com/google/appengine/appengine-tools-sdk/1.9.60/appengine-tools-sdk-1.9.60-sources.jar

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

Deprecated Gradle features were used in this build, making it incompatible with Gradle 5.0.
See https://docs.gradle.org/4.8.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD FAILED in 0s
1 actionable task: 1 executed
11:57:04 PM: Task execution finished 'DownloadSources'.

This leads me to believe that at this stage of the game where the get-openapi-doc command is actually evaluated, it's closed source?

My main reason for doing all of this is because in my view, the endpoints framework plugin documentation/functionality (https://cloud.google.com/endpoints/docs/frameworks/java/maven-endpoints-frameworks-plugin) is very sparse and

a) doesn't allow for output in yaml format, which is much more friendly than json
b) doesn't have any options to enable requiring api keys (https://cloud.google.com/endpoints/docs/openapi/restricting-api-access-with-api-keys) which also is demoed in yaml format and doesn't seem to be part of the plugin feature set