Add fish shell format for export-credentials (aws#9996)

Author: minjcho

.changes/next-release/enhancement-configure-99484.json

@@ -0,0 +1,5 @@
+{
+  "type": "enhancement",
+  "category": "configure",
+  "description": "Add fish shell format for export-credentials command (fixes `#9670 <https://github.com/aws/aws-cli/issues/9670>`__)"
+}

awscli/customizations/configure/exportcreds.py

@@ -117,6 +117,15 @@ class WindowsCmdFormatter(BasePerLineFormatter):
     _VAR_FORMAT = 'set {var_name}={var_value}'
 
 
+class FishShellFormatter(BasePerLineFormatter):
+    FORMAT = 'fish'
+    DOCUMENTATION = (
+        'Display credentials as Fish shell environment variables: '
+        '``set -gx AWS_ACCESS_KEY_ID "EXAMPLE"``'
+    )
+    _VAR_FORMAT = 'set -gx {var_name} "{var_value}"'
+
+
 class CredentialProcessFormatter(BaseCredentialFormatter):
     FORMAT = 'process'
     DOCUMENTATION = (
@@ -152,6 +161,7 @@ def display_credentials(self, credentials):
         BashNoExportEnvFormatter,
         PowershellFormatter,
         WindowsCmdFormatter,
+        FishShellFormatter,
     ]
 }
 

tests/unit/customizations/configure/test_exportcreds.py

@@ -26,6 +26,7 @@
     ConfigureExportCredentialsCommand,
     CredentialProcessFormatter,
     Credentials,
+    FishShellFormatter,
     PowershellFormatter,
     WindowsCmdFormatter,
     convert_botocore_credentials,
@@ -109,6 +110,21 @@ def __eq__(self, other):
                 ),
             ),
         ),
+        (
+            FishShellFormatter,
+            (
+                (
+                    'set -gx AWS_ACCESS_KEY_ID "access_key"\n'
+                    'set -gx AWS_SECRET_ACCESS_KEY "secret_key"\n'
+                ),
+                (
+                    'set -gx AWS_ACCESS_KEY_ID "access_key"\n'
+                    'set -gx AWS_SECRET_ACCESS_KEY "secret_key"\n'
+                    'set -gx AWS_SESSION_TOKEN "token"\n'
+                    'set -gx AWS_CREDENTIAL_EXPIRATION "2023-01-01T00:00:00Z"\n'
+                ),
+            ),
+        ),
         (
             CredentialProcessFormatter,
             (