Add --add-host cli option to expose docker container option with the same name.

samcli/cli/types.py

@@ -453,6 +453,33 @@ def convert(self, value, param, ctx):
         return {key: _value}
 
 
+class DockerAdditionalHostType(click.ParamType):
+    """
+    Custom Parameter Type for managing Docker container's host file for local commands
+    """
+
+    name = "list"
+    MIN_KEY_VALUE_PAIR_LENGTH = 2
+
+    def convert(self, value, param, ctx):
+        """Converts the user provided parameters value with the format "host:IP" to dict
+            {"host": "IP"}
+
+        Parameters
+        ------------
+        value: User provided value for the click option
+        param: click parameter
+        ctx: Context
+        """
+        host_ip_pair = value.split(":", maxsplit=1)
+        if len(host_ip_pair) < self.MIN_KEY_VALUE_PAIR_LENGTH:
+            raise click.BadParameter(f"{param.opts[0]} is not a valid format, it needs to be of the form hostname:IP")
+        host = host_ip_pair[0]
+        ip = host_ip_pair[1]
+        LOG.debug("Converting provided %s option value to dict", param.opts[0])
+        return {host: ip}
+
+
 class RemoteInvokeOutputFormatType(click.Choice):
     """
     Custom Parameter Type for output-format option of remote invoke command.

samcli/commands/_utils/options.py

@@ -156,6 +156,21 @@ def remote_invoke_boto_parameter_callback(ctx, param, provided_value):
     return boto_api_parameters
 
 
+def local_add_host_callback(ctx, param, provided_value):
+    """
+    Create a dictionary of hostnames to IP addresses to add into Docker container's hosts file.
+    :param ctx: Click Context
+    :param param: Param name
+    :param provided_value: Value provided by Click, after being processed by DockerAdditionalHostType.
+    :return: dictionary of hostnames to IP addresses.
+    """
+    extra_hosts = {}
+    for value in provided_value:
+        extra_hosts.update(value)
+
+    return extra_hosts
+
+
 def artifact_callback(ctx, param, provided_value, artifact):
     """
     Provide an error if there are zip/image artifact based resources,

samcli/commands/local/cli_common/invoke_context.py

@@ -97,6 +97,7 @@ def __init__(
         shutdown: bool = False,
         container_host: Optional[str] = None,
         container_host_interface: Optional[str] = None,
+        add_host: Optional[dict] = None,
         invoke_images: Optional[str] = None,
     ) -> None:
         """
@@ -148,6 +149,8 @@ def __init__(
             Optional. Host of locally emulated Lambda container
         container_host_interface string
             Optional. Interface that Docker host binds ports to
+        add_host dict
+            Optional. Docker extra hosts support from --add-host parameters
         invoke_images dict
             Optional. A dictionary that defines the custom invoke image URI of each function
         """
@@ -177,6 +180,9 @@ def __init__(
 
         self._container_host = container_host
         self._container_host_interface = container_host_interface
+
+        self._extra_hosts: Optional[Dict] = add_host
+
         self._invoke_images = invoke_images
 
         self._containers_mode = ContainersMode.COLD
@@ -396,6 +402,7 @@ def local_lambda_runner(self) -> LocalLambdaRunner:
             debug_context=self._debug_context,
             container_host=self._container_host,
             container_host_interface=self._container_host_interface,
+            extra_hosts=self._extra_hosts,
         )
         return self._local_lambda_runner
 

samcli/commands/local/cli_common/options.py

@@ -5,7 +5,13 @@
 
 import click
 
-from samcli.commands._utils.options import docker_click_options, parameter_override_click_option, template_click_option
+from samcli.cli.types import DockerAdditionalHostType
+from samcli.commands._utils.options import (
+    docker_click_options,
+    local_add_host_callback,
+    parameter_override_click_option,
+    template_click_option,
+)
 from samcli.commands.local.cli_common.invoke_context import ContainersInitializationMode
 from samcli.local.docker.container import DEFAULT_CONTAINER_HOST_INTERFACE
 
@@ -65,6 +71,18 @@ def local_common_options(f):
             help="IP address of the host network interface that container ports should bind to. "
             "Use 0.0.0.0 to bind to all interfaces.",
         ),
+        click.option(
+            "--add-host",
+            multiple=True,
+            type=DockerAdditionalHostType(),
+            callback=local_add_host_callback,
+            required=False,
+            help="Passes a hostname to IP address mapping to the Docker container's host file. "
+            "This parameter can be passed multiple times."
+            ""
+            "Example:"
+            "--add-host example.com:127.0.0.1",
+        ),
         click.option(
             "--invoke-image",
             "-ii",

samcli/commands/local/invoke/cli.py

@@ -90,6 +90,7 @@ def cli(
     config_env,
     container_host,
     container_host_interface,
+    add_host,
     invoke_image,
     hook_name,
     skip_prepare_infra,
@@ -121,6 +122,7 @@ def cli(
         parameter_overrides,
         container_host,
         container_host_interface,
+        add_host,
         invoke_image,
         hook_name,
     )  # pragma: no cover
@@ -147,6 +149,7 @@ def do_cli(  # pylint: disable=R0914
     parameter_overrides,
     container_host,
     container_host_interface,
+    add_host,
     invoke_image,
     hook_name,
 ):
@@ -195,6 +198,7 @@ def do_cli(  # pylint: disable=R0914
             shutdown=shutdown,
             container_host=container_host,
             container_host_interface=container_host_interface,
+            add_host=add_host,
             invoke_images=processed_invoke_images,
         ) as context:
             # Invoke the function

samcli/commands/local/invoke/core/options.py

@@ -32,6 +32,7 @@
     "shutdown",
     "container_host",
     "container_host_interface",
+    "add_host",
     "invoke_image",
 ]
 

samcli/commands/local/lib/local_lambda.py

@@ -51,6 +51,7 @@ def __init__(
         debug_context: Optional[DebugContext] = None,
         container_host: Optional[str] = None,
         container_host_interface: Optional[str] = None,
+        extra_hosts: Optional[dict] = None,
     ) -> None:
         """
         Initializes the class
@@ -65,6 +66,7 @@ def __init__(
         :param DebugContext debug_context: Optional. Debug context for the function (includes port, args, and path).
         :param string container_host: Optional. Host of locally emulated Lambda container
         :param string container_host_interface: Optional. Interface that Docker host binds ports to
+        :param dict extra_hosts: Optional. Dict of hostname to IP resolutions
         """
 
         self.local_runtime = local_runtime
@@ -78,6 +80,7 @@ def __init__(
         self._boto3_region: Optional[str] = None
         self.container_host = container_host
         self.container_host_interface = container_host_interface
+        self.extra_hosts = extra_hosts
 
     def invoke(
         self,
@@ -149,6 +152,7 @@ def invoke(
                 stderr=stderr,
                 container_host=self.container_host,
                 container_host_interface=self.container_host_interface,
+                extra_hosts=self.extra_hosts,
             )
         except ContainerResponseException:
             # NOTE(sriram-mv): This should still result in a exit code zero to avoid regressions.

samcli/commands/local/start_api/cli.py

@@ -134,6 +134,7 @@ def cli(
     debug_function,
     container_host,
     container_host_interface,
+    add_host,
     invoke_image,
     hook_name,
     skip_prepare_infra,
@@ -170,6 +171,7 @@ def cli(
         debug_function,
         container_host,
         container_host_interface,
+        add_host,
         invoke_image,
         hook_name,
         ssl_cert_file,

samcli/commands/local/start_api/core/options.py

@@ -38,6 +38,7 @@
     "shutdown",
     "container_host",
     "container_host_interface",
+    "add_host",
     "invoke_image",
     "disable_authorizer",
 ]

samcli/commands/local/start_lambda/cli.py

@@ -96,6 +96,7 @@ def cli(
     debug_function,
     container_host,
     container_host_interface,
+    add_host,
     invoke_image,
     hook_name,
     skip_prepare_infra,
@@ -128,6 +129,7 @@ def cli(
         debug_function,
         container_host,
         container_host_interface,
+        add_host,
         invoke_image,
         hook_name,
     )  # pragma: no cover
@@ -155,6 +157,7 @@ def do_cli(  # pylint: disable=R0914
     debug_function,
     container_host,
     container_host_interface,
+    add_host,
     invoke_image,
     hook_name,
 ):
@@ -200,6 +203,7 @@ def do_cli(  # pylint: disable=R0914
             shutdown=shutdown,
             container_host=container_host,
             container_host_interface=container_host_interface,
+            add_host=add_host,
             invoke_images=processed_invoke_images,
         ) as invoke_context:
             service = LocalLambdaService(lambda_invoke_context=invoke_context, port=port, host=host)

samcli/commands/local/start_lambda/core/options.py

@@ -34,6 +34,7 @@
     "shutdown",
     "container_host",
     "container_host_interface",
+    "add_host",
     "invoke_image",
 ]
 

samcli/local/docker/container.py

@@ -79,6 +79,7 @@ def __init__(
         container_host_interface=DEFAULT_CONTAINER_HOST_INTERFACE,
         mount_with_write: bool = False,
         host_tmp_dir: Optional[str] = None,
+        extra_hosts: Optional[dict] = None,
     ):
         """
         Initializes the class with given configuration. This does not automatically create or run the container.
@@ -100,6 +101,7 @@ def __init__(
         :param bool mount_with_write: Optional. Mount source code directory with write permissions when
             building on container
         :param string host_tmp_dir: Optional. Temporary directory on the host when mounting with write permissions.
+        :param dict extra_hosts: Optional. Dict of hostname to IP resolutions
         """
 
         self._image = image
@@ -114,6 +116,7 @@ def __init__(
         self._container_opts = container_opts
         self._additional_volumes = additional_volumes
         self._logs_thread = None
+        self._extra_hosts = extra_hosts
         self._logs_thread_event = None
 
         # Use the given Docker client or create new one
@@ -215,6 +218,9 @@ def create(self):
             # Ex: 128m => 128MB
             kwargs["mem_limit"] = "{}m".format(self._memory_limit_mb)
 
+        if self._extra_hosts:
+            kwargs["extra_hosts"] = self._extra_hosts
+
         real_container = self.docker_client.containers.create(self._image, **kwargs)
         self.id = real_container.id
 

samcli/local/docker/lambda_container.py

@@ -51,6 +51,7 @@ def __init__(
         debug_options=None,
         container_host=None,
         container_host_interface=DEFAULT_CONTAINER_HOST_INTERFACE,
+        extra_hosts=None,
         function_full_path=None,
     ):
         """
@@ -87,6 +88,8 @@ def __init__(
             Optional. Host of locally emulated Lambda container
         container_host_interface
             Optional. Interface that Docker host binds ports to
+        extra_hosts
+            Optional. Dict of hostname to IP resolutions
         function_full_path str
             Optional. The function full path, unique in all stacks
         """
@@ -138,6 +141,7 @@ def __init__(
             additional_volumes=additional_volumes,
             container_host=container_host,
             container_host_interface=container_host_interface,
+            extra_hosts=extra_hosts,
         )
 
     @staticmethod

samcli/local/lambdafn/runtime.py

@@ -49,7 +49,9 @@ def __init__(self, container_manager, image_builder):
         self._image_builder = image_builder
         self._temp_uncompressed_paths_to_be_cleaned = []
 
-    def create(self, function_config, debug_context=None, container_host=None, container_host_interface=None):
+    def create(
+        self, function_config, debug_context=None, container_host=None, container_host_interface=None, extra_hosts=None
+    ):
         """
         Create a new Container for the passed function, then store it in a dictionary using the function name,
         so it can be retrieved later and used in the other functions. Make sure to use the debug_context only
@@ -100,6 +102,7 @@ def create(self, function_config, debug_context=None, container_host=None, conta
             debug_options=debug_context,
             container_host=container_host,
             container_host_interface=container_host_interface,
+            extra_hosts=extra_hosts,
             function_full_path=function_config.full_path,
         )
         try:
@@ -162,6 +165,7 @@ def invoke(
         stderr: Optional[StreamWriter] = None,
         container_host=None,
         container_host_interface=None,
+        extra_hosts=None,
     ):
         """
         Invoke the given Lambda function locally.
@@ -184,12 +188,16 @@ def invoke(
             Host of locally emulated Lambda container
         :param string container_host_interface: Optional.
             Interface that Docker host binds ports to
+        :param dict extra_hosts: Optional.
+            Dict of hostname to IP resolutions
         :raises Keyboard
         """
         container = None
         try:
             # Start the container. This call returns immediately after the container starts
-            container = self.create(function_config, debug_context, container_host, container_host_interface)
+            container = self.create(
+                function_config, debug_context, container_host, container_host_interface, extra_hosts
+            )
             container = self.run(container, function_config, debug_context)
             # Setup appropriate interrupt - timeout or Ctrl+C - before function starts executing and
             # get callback function to start timeout timer
@@ -375,7 +383,9 @@ def __init__(self, container_manager, image_builder, observer=None):
 
         super().__init__(container_manager, image_builder)
 
-    def create(self, function_config, debug_context=None, container_host=None, container_host_interface=None):
+    def create(
+        self, function_config, debug_context=None, container_host=None, container_host_interface=None, extra_hosts=None
+    ):
         """
         Create a new Container for the passed function, then store it in a dictionary using the function name,
         so it can be retrieved later and used in the other functions. Make sure to use the debug_context only
@@ -429,7 +439,9 @@ def create(self, function_config, debug_context=None, container_host=None, conta
         self._observer.watch(function_config)
         self._observer.start()
 
-        container = super().create(function_config, debug_context, container_host, container_host_interface)
+        container = super().create(
+            function_config, debug_context, container_host, container_host_interface, extra_hosts
+        )
         self._function_configs[function_config.full_path] = function_config
         self._containers[function_config.full_path] = container