add ssh key authentication support, closes #81

hyperglass/models/config/credential.py

@@ -1,14 +1,42 @@
 """Validate credential configuration variables."""
 
+# Standard Library
+from typing import Optional
+
 # Third Party
-from pydantic import SecretStr, StrictStr
+from pydantic import FilePath, SecretStr, StrictStr, constr, root_validator
 
 # Local
-from ..main import HyperglassModel
+from ..main import HyperglassModelExtra
+
+Methods = constr(regex=r"(password|unencrypted_key|encrypted_key)")
 
 
-class Credential(HyperglassModel):
+class Credential(HyperglassModelExtra):
     """Model for per-credential config in devices.yaml."""
 
     username: StrictStr
-    password: SecretStr
+    password: Optional[SecretStr]
+    key: Optional[FilePath]
+
+    @root_validator
+    def validate_credential(cls, values):
+        """Ensure either a password or an SSH key is set."""
+        if values["key"] is None and values["password"] is None:
+            raise ValueError(
+                "Either a password or an SSH key must be specified for user '{}'".format(
+                    values["username"]
+                )
+            )
+        return values
+
+    def __init__(self, **kwargs):
+        """Set private attribute _method based on validated model."""
+        super().__init__(**kwargs)
+        self._method = None
+        if self.password is not None and self.key is not None:
+            self._method = "encrypted_key"
+        elif self.password is None:
+            self._method = "unencrypted_key"
+        elif self.key is None:
+            self._method = "password"