sqs.changeMessageVisibility according to [this](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_ChangeMessageVisibility.html#API_ChangeMessageVisibility_Examples) makes a request directly to the Queue's URL rather than via the SQS Endpoint. (I'm already setting SQS endpoint to LOCALSTACK_HOSTNAME - makes no difference for this call)..

In localstack the queue URL host returned is by default set to the value of HOSTNAME_EXTERNAL, which I'm setting to localstack, but calling this method within a lambda, does not work and I get the error:

```
UnknownEndpoint: Inaccessible host: `localstack'. This service may not be available in the `us-east-1' region. 
```

So, how can I make the queue URL accessible from within a lambda using localstack? Effectively I need to make **http://localstack** accessible from within lambda.

I'm using the following cmd to start localstack:

```
LAMBDA_EXECUTOR=docker-reuse DEBUG=1 LAMBDA_REMOTE_DOCKER=0 DATA_DIR=/tmp/localstack/data HOSTNAME_EXTERNAL=localstack localstack start
```
LAMBDA_RUNTIME_PYTHON27,
    LAMBDA_RUNTIME_PYTHON36,
    LAMBDA_RUNTIME_NODEJS,
    LAMBDA_RUNTIME_NODEJS610,
    LAMBDA_RUNTIME_NODEJS810,
    LAMBDA_RUNTIME_JAVA8,
    LAMBDA_RUNTIME_JAVA11,
    LAMBDA_RUNTIME_DOTNETCORE2,
    LAMBDA_RUNTIME_DOTNETCORE21,
    LAMBDA_RUNTIME_GOLANG,
    LAMBDA_RUNTIME_RUBY,
    LAMBDA_RUNTIME_RUBY25,
    LAMBDA_RUNTIME_PROVIDED)
from localstack.utils.common import (to_str, load_file, save_file, TMP_FILES, ensure_readable,
    mkdir, unzip, is_zip_file, zip_contains_jar_entries, run, short_uid, timestamp,
    TIMESTAMP_FORMAT_MILLIS, md5, parse_chunked_data, now_utc, safe_requests,
    isoformat_milliseconds)
from localstack.utils.analytics import event_publisher
from localstack.utils.aws.aws_models import LambdaFunction
from localstack.utils.cloudwatch.cloudwatch_util import cloudwatched
APP_NAME = 'lambda_api'
PATH_ROOT = '/2015-03-31'
ARCHIVE_FILE_PATTERN = '%s/lambda.handler.*.jar' % config.TMP_FOLDER
LAMBDA_SCRIPT_PATTERN = '%s/lambda_script_*.py' % config.TMP_FOLDER
LAMBDA_RUNTIMES = [LAMBDA_RUNTIME_PYTHON27, LAMBDA_RUNTIME_PYTHON36,
    LAMBDA_RUNTIME_DOTNETCORE2, LAMBDA_RUNTIME_DOTNETCORE21, LAMBDA_RUNTIME_NODEJS,
    LAMBDA_RUNTIME_NODEJS610, LAMBDA_RUNTIME_NODEJS810, LAMBDA_RUNTIME_JAVA8,
    LAMBDA_RUNTIME_JAVA11, LAMBDA_RUNTIME_RUBY, LAMBDA_RUNTIME_RUBY25]
LAMBDA_DEFAULT_TIMEOUT = 3
LAMBDA_DEFAULT_HANDLER = 'handler.handler'