### Writing controllers

Istio provides a few helper libraries to get started writing a controller. While these libraries help, there are still a lot of subtleties in correctly writing (and testing!) a controller properly.

To get started writing a controller, review the [Example Controller](../../pkg/kube/controllers/example_test.go).

### Controllers overview

  // not specified, it will be defaulted to 50.
  // +optional
  optional int32 queueLengthLimit = 3;
}

// ResourcePolicyRule is a predicate that matches some resource
// requests, testing the request's verb and the target resource. A
// ResourcePolicyRule matches a resource request if and only if: (a)
// at least one member of verbs matches the request, (b) at least one

* Durch die Verwendung einer Abhängigkeit können Sie das Testen vereinfachen.
* Sie können `.env`-Dateien damit verwenden.

    h ^= (h >>> 10);
    h += (h << 3);
    h ^= (h >>> 6);
    h += (h << 2) + (h << 14);
    return h ^ (h >>> 16);
  }

  /**
   * This method is a convenience for testing. Code should call {@link Segment#copyEntry} directly.
   */
  // Guarded By Segment.this
  @VisibleForTesting
  E copyEntry(E original, E newNext) {
    int hash = original.getHash();

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Maps;
import com.google.common.primitives.Primitives;
import com.google.common.testing.EqualsTester;
import com.google.common.testing.NullPointerTester;
import com.google.common.testing.SerializableTester;
import com.google.common.truth.IterableSubject;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.Serializable;

import com.google.common.base.Suppliers;
import com.google.common.base.Throwables;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.testing.ClassSanityTester;
import com.google.common.util.concurrent.MoreExecutors.Application;
import java.lang.Thread.State;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import static com.google.common.collect.Range.range;
import static com.google.common.truth.Truth.assertThat;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.testing.SerializableTester;
import java.util.List;
import java.util.NavigableMap;

/**
 * Tests for {@link TreeRangeSet}.
 *
 * @author Louis Wasserman
 * @author Chris Povirk
 */
@GwtIncompatible // TreeRangeSet

        /*
         * We wish to test whether or not x <= (sqrtFloor + 0.5)^2 = halfSquare + 0.25. Since both x
         * and halfSquare are integers, this is equivalent to testing whether or not x <=
         * halfSquare.
         */
        return (halfSquare.compareTo(x) >= 0) ? sqrtFloor : sqrtFloor.add(BigInteger.ONE);
    }
    throw new AssertionError();
  }

or using `mc`

```
mc admin config get myminio identity_openid
identity_openid config_url=https://accounts.google.com/.well-known/openid-configuration client_id=843351d4-1080-11ea-aa20-271ecba3924a
```

Testing with an example
> Visit [Google Developer Console](https://console.cloud.google.com) under Project, APIs, Credentials to get your OAuth2 client credentials. Add `http://localhost:8080/oauth2/callback` as a valid OAuth2 Redirect URL.

In-tree cloud provider bug fixes and improvements included:
- Adding initial Zones support to the provider using vSphere Tags
- Improving the testing harness for the cloud provider by introducing vcsim for automated testing
- Fixing a bug that was preventing updates from 1.10 to 1.11