## Context Managers

### What are "Context Managers"

"Context Managers" are any of those Python objects that you can use in a `with` statement.

```jinja hl_lines="7"
{!../../docs_src/templates/templates/item.html!}
```

### Template Context Values

In the HTML that contains:

{% raw %}

```jinja
Item ID: {{ id }}
```

{% endraw %}

...it will show the `id` taken from the "context" `dict` you passed:

```Python
{"id": id}
```

For example, with an ID of `42`, this would render:

```html

	}
	if len(extKey) != 32 { // safety check
		logger.CriticalIf(context.Background(), errors.New("crypto: invalid key length"))
	}
	var nonce [32]byte
	if _, err := io.ReadFull(random, nonce[:]); err != nil {
		logger.CriticalIf(context.Background(), errOutOfEntropy)
	}

	const Context = "object-encryption-key generation"
	mac := hmac.New(sha256.New, extKey)
	mac.Write([]byte(Context))
	mac.Write(nonce[:])
	mac.Sum(key[:0])
	return key

			func(t *testing.T) {
				runAllIAMSTSTests(testCase, &check{t, testCase.serverType})
			},
		)
	}
}

func (s *TestSuiteIAM) TestSTSServiceAccountsWithUsername(c *check) {
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	bucket := "dillon-bucket"
	err := s.client.MakeBucket(ctx, bucket, minio.MakeBucketOptions{})
	if err != nil {
		c.Fatalf("bucket create error: %v", err)
	}

The handler function has this signature.

Sample handler:
```go
    handler :=  func(ctx context.Context, payload []byte, in <-chan []byte, out chan<- []byte) *RemoteErr {
        fmt.Println("Got request with initial payload", p, "from", GetCaller(ctx context.Context))
        fmt.Println("Subroute:", GetSubroute(ctx))
        for {
            select {
            case <-ctx.Done():

			key := msgPath(fmt.Sprintf("%s.%s", bucket, domainName), c.prefixPath)
			key = key + etcdPathSeparator + ip
			ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
			_, err = c.etcdClient.Put(ctx, key, string(bucketMsg))
			cancel()
			if err != nil {
				ctx, cancel = context.WithTimeout(context.Background(), defaultContextTimeout)
				c.etcdClient.Delete(ctx, key)
				cancel()
				return err
			}
		}

 */
package jcifs.context;


import jcifs.CIFSContext;
import jcifs.Credentials;
import jcifs.smb.CredentialsInternal;
import jcifs.smb.NtlmAuthenticator;
import jcifs.smb.NtlmPasswordAuthenticator;
import jcifs.smb.SmbAuthException;
import jcifs.smb.SmbRenewableCredentials;


/**
 * Context wrapper supplying alternate credentials
 * 
 * @author mbechler
 *

	bucket := "minio-bucket"
	object := "minio-object"

	// Create bucket.
	err := obj.MakeBucket(context.Background(), bucket, MakeBucketOptions{})
	if err != nil {
		// Failed to create newbucket, abort.
		t.Fatalf("%s : %s", instanceType, err.Error())
	}

	// Creating a dummy bucket for tests.
	err = obj.MakeBucket(context.Background(), "unused-bucket", MakeBucketOptions{})
	if err != nil {
		// Failed to create newbucket, abort.

	addedPods   atomic.Int32
	addError    error
	delError    error
}

func (f *fakeZtunnel) Run(ctx context.Context) {
}

func (f *fakeZtunnel) PodDeleted(ctx context.Context, uid string) error {
	f.deletedPods.Add(1)
	return f.delError
}

func (f *fakeZtunnel) PodAdded(ctx context.Context, pod *corev1.Pod, netns Netns) error {
	f.addedPods.Add(1)
	return f.addError
}

	// This bucket is used for testing getObjectInfo operations.
	err := obj.MakeBucket(context.Background(), "test-getobjectinfo", MakeBucketOptions{})
	if err != nil {
		t.Fatalf("%s : %s", instanceType, err.Error())
	}
	opts := ObjectOptions{}