Can't access localhost in bazel 0.3.2

[dfabulich]

Consider this repository. https://github.com/dfabulich/bazel-localhost-test

It has a simple WORKSPACE declaring junit and hamcrest_core.

maven_jar(
	name='junit',
	artifact='junit:junit:4.12'
)

maven_jar(
	name='hamcrest_core',
	artifact='org.hamcrest:hamcrest-core:1.3'
)

And the BUILD file has just one test target with the requires-network tag:

java_test(
	name='apptest',
	srcs=glob(['src/test/java/**']),
	test_class='com.redfin.AppTest',
	size="small",
	tags=["requires-network"],
	deps=['@junit//jar', '@hamcrest_core//jar'],
)

The test itself just attempts to print the localhost's hostname.

package com.redfin;

import org.junit.Test;
import java.net.*;
import java.io.*;

public class AppTest {

        @Test
        public void testGo() throws Exception {
                System.out.println(InetAddress.getLocalHost().getHostName());
        }
}

This test passes in bazel 0.3.1 on Ubuntu 16.04.

bazel 0.3.1 version details

Build label: 0.3.1
Build target: bazel-out/local-fastbuild/bin/src/main/java/com/google/devtools/build/lib/bazel/BazelServer_deploy.jar
Build time: Fri Jul 29 09:09:52 2016 (1469783392)
Build timestamp: 1469783392
Build timestamp as int: 1469783392

But on bazel 0.3.2 it fails.

stacktrace

java.net.UnknownHostException: sandbox: sandbox: unknown error
	at java.net.InetAddress.getLocalHost(InetAddress.java:1505)
	at com.redfin.AppTest.testGo(AppTest.java:11)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at com.google.testing.junit.runner.junit4.CancellableRequestFactory$CancellableRunner.run(CancellableRequestFactory.java:90)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:138)
	at com.google.testing.junit.runner.junit4.JUnit4Runner.run(JUnit4Runner.java:112)
	at com.google.testing.junit.runner.BazelTestRunner.runTestsInSuite(BazelTestRunner.java:140)
	at com.google.testing.junit.runner.BazelTestRunner.main(BazelTestRunner.java:79)
Caused by: java.net.UnknownHostException: sandbox: unknown error
	at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
	at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928)
	at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)
	at java.net.InetAddress.getLocalHost(InetAddress.java:1500)
	... 24 more

bazel 0.3.2 version details

Build label: 0.3.2
Build target: bazel-out/local-fastbuild/bin/src/main/java/com/google/devtools/build/lib/bazel/BazelServer_deploy.jar
Build time: Fri Oct 7 17:25:10 2016 (1475861110)
Build timestamp: 1475861110
Build timestamp as int: 1475861110

[dfabulich]

This also fails in Bazel 0.4rc3 on Ubuntu 16.04, with the same stacktrace.

Build label: 0.4.0rc3
Build target: bazel-out/local-fastbuild/bin/src/main/java/com/google/devtools/build/lib/bazel/BazelServer_deploy.jar
Build time: Wed Oct 26 13:47:46 2016 (1477489666)
Build timestamp: 1477489666
Build timestamp as int: 1477489666

[dfabulich]

Is there a workaround possible for this, other than just running the tests outside the sandbox? I thought requires-network should have done the trick, but it didn't.

[laszlocsomor]

Ugh, sorry for the long silence. Redirecting to our sandbox expert @philwo .

[dfabulich]

ping?

[dfabulich]

@philwo have you had a chance to look at this issue yet? If you (or anybody) can give me a hint where to start, I can try to pull together a pull request.

[philwo]

@dfabulich So sorry for the delay! I will add your test to the test suite of the sandbox, figure out why it's not working and then fix it. Hope to have something by the end of today.

[philwo]

The reason for this failure is that SetupUtsNamespace in linux-sandbox-pid1.cc sets the hostname and domainname to "sandbox", which cannot be resolved via /etc/hosts or DNS, which results in the error you're seeing.

I think I'll just set the hostname inside the sandbox to "localhost" and the domainname to an empty value. This should fix the issue (because "localhost" can usually be resolved) and still not leak anything.

Would that work for you? Or would you prefer the hostname to not change at all and the original hostname be visible inside the sandbox?

[dfabulich]

I don't have time to test it today, but it "works for me" if the https://github.com/dfabulich/bazel-localhost-test test passes.