Make the "port forwarding create" command idempotent

The `port forwarding create` command would exit with an error
if you attempted to create a forwarding configuration that already exists.
This made it difficult to identify actual failures.

This commit updates the `port forwarding create` command so that it is not
an error if the requested forwarding already exists.

The old behavior was:

    $ openstack esi port forwarding create 192.168.11.31 128.31.20.118 -p 8888
    +--------------------------------------+---------------+---------------+----------+---------------+---------------+
    | ID                                   | Internal Port | External Port | Protocol | Internal IP   | External IP   |
    +--------------------------------------+---------------+---------------+----------+---------------+---------------+
    | 43c96be3-861d-4818-a32a-079a93b6f9c4 |          8888 |          8888 | tcp      | 192.168.11.31 | 128.31.20.118 |
    +--------------------------------------+---------------+---------------+----------+---------------+---------------+
    $ openstack esi port forwarding create esi-MOC-R4PAC24U35-S1B-provisioning 128.31.20.118 -p 8888 -p 8889
    BadRequestException: 400: Client Error for url:
    https://esi.massopen.cloud:13696/v2.0/floatingips/be4b2718-ec5f-4722-80b5-485c421e4a72/port_forwardings,
    Bad port_forwarding request: A duplicate port forwarding entry with
    same attributes already exists, conflicting values are
    {'floatingip_id': 'be4b2718-ec5f-4722-80b5-485c421e4a72',
    'external_port': 8888, 'protocol': 'tcp'}.

The new behavior looks like this:

    $ openstack esi port forwarding create 192.168.11.31 128.31.20.118 -p 8888
    +--------------------------------------+---------------+---------------+----------+---------------+---------------+
    | ID                                   | Internal Port | External Port | Protocol | Internal IP   | External IP   |
    +--------------------------------------+---------------+---------------+----------+---------------+---------------+
    | 43c96be3-861d-4818-a32a-079a93b6f9c4 |          8888 |          8888 | tcp      | 192.168.11.31 | 128.31.20.118 |
    +--------------------------------------+---------------+---------------+----------+---------------+---------------+
    $ openstack esi port forwarding create esi-MOC-R4PAC24U35-S1B-provisioning 128.31.20.118 -p 8888 -p 8889
    +--------------------------------------+---------------+---------------+----------+---------------+---------------+
    | ID                                   | Internal Port | External Port | Protocol | Internal IP   | External IP   |
    +--------------------------------------+---------------+---------------+----------+---------------+---------------+
    | exists                               |          8888 |          8888 | tcp      | 192.168.11.31 | 128.31.20.118 |
    | d7d56201-232a-41fe-8ae6-1f6fb88a37d3 |          8889 |          8889 | tcp      | 192.168.11.31 | 128.31.20.118 |
    +--------------------------------------+---------------+---------------+----------+---------------+---------------+

Author: larsks

esiclient/v1/port_forwarding.py

@@ -1,3 +1,5 @@
+# pyright: basic
+
 #   Licensed under the Apache License, Version 2.0 (the "License"); you may
 #   not use this file except in compliance with the License. You may obtain
 #   a copy of the License at
@@ -34,6 +36,15 @@ class Protocol(str, Enum):
     UDP = "udp"
 
 
+@dataclass
+class FwdSpec:
+    id: str
+    internal_port: str
+    external_port: str
+    protocol: str
+    internal_ip_address: str
+
+
 @dataclass
 class PortSpec:
     """Represent a port forwarding from an external port to an internal port"""
@@ -73,7 +84,6 @@ def from_spec(cls, spec: str):
 
 
 def PortSpecArg(v):
-    """this is a test"""
     try:
         return PortSpec.from_spec(v)
     except ValueError as err:
@@ -233,6 +243,18 @@ def find_or_create_port(
             )
 
 
+def port_forwarding_exists(fip, internal_ip_address, port):
+    for check in fip.port_forwardings:
+        fwd = FwdSpec(id="exists", **check)
+        if (
+            port.int_port == fwd.internal_port
+            and port.ext_port == fwd.external_port
+            and internal_ip_address == fwd.internal_ip_address
+            and port.protocol == fwd.protocol
+        ):
+            return fwd
+
+
 def format_forwards(func):
     """A decorator that transforms a list of (floating_ip, port_forwarding) tuples
     into a list suitable for a cliff command.Lister"""
@@ -329,21 +351,25 @@ def take_action(self, parsed_args: argparse.Namespace):
             # rather than the port.
             internal_ip_address = internal_port.fixed_ips[0]["ip_address"]
 
+        # [{'external_port': 8888, 'protocol': 'tcp', 'internal_ip_address': '192.168.11.31', 'internal_port': 8888}]
         for port in parsed_args.port:
-            fwd = self.app.client_manager.sdk_connection.network.create_floating_ip_port_forwarding(
-                fip,
-                internal_ip_address=internal_ip_address,
-                internal_port=port.int_port,
-                internal_port_id=internal_port.id,
-                external_port=port.ext_port,
-                protocol=port.protocol,
-                **(
-                    {"description": parsed_args.description}
-                    if parsed_args.description
-                    else {}
-                ),
-            )
-            forwards.append((fip, fwd))
+            if fwd := port_forwarding_exists(fip, internal_ip_address, port):
+                forwards.append((fip, fwd))
+            else:
+                fwd = self.app.client_manager.sdk_connection.network.create_floating_ip_port_forwarding(
+                    fip,
+                    internal_ip_address=internal_ip_address,
+                    internal_port=port.int_port,
+                    internal_port_id=internal_port.id,
+                    external_port=port.ext_port,
+                    protocol=port.protocol,
+                    **(
+                        {"description": parsed_args.description}
+                        if parsed_args.description
+                        else {}
+                    ),
+                )
+                forwards.append((fip, fwd))
 
         return forwards