Improve error handling in config loading and exceptions for better clarity on missing or malformed config keys.

README.rst

@@ -9,16 +9,14 @@ This is the Python SDK for Oracle Cloud Infrastructure. Supported Python version
 
 __ https://docs.oracle.com/en-us/iaas/Content/API/SDKDocs/pythonsdk.htm#pythonsdk_topic-supported_python_versions
 
+Quickstart
+==========
+
 .. code-block:: pycon
 
     >>> import oci
-    # Set up config
-    >>> config = oci.config.from_file(
-    ...     "~/.oci/config",
-    ...     "DEFAULT")
-    # Create a service client
+    >>> config = oci.config.from_file()
     >>> identity = oci.identity.IdentityClient(config)
-    # Get the current user
     >>> user = identity.get_user(config["user"]).data
     >>> print(user)
     {
@@ -31,6 +29,26 @@ __ https://docs.oracle.com/en-us/iaas/Content/API/SDKDocs/pythonsdk.htm#pythonsd
       "time_created": "2016-08-30T23:46:44.680000+00:00"
     }
 
+If you need to load a different profile or config file:
+
+.. code-block:: pycon
+
+    >>> config = oci.config.from_file("~/.oci/config", "DEFAULT")
+
+You can also point the SDK at a config file via environment variable:
+
+.. code-block:: sh
+
+    OCI_CONFIG_FILE=~/.oci/config python your_script.py
+
+Instance principals (running on an OCI compute instance) can be used without a config file:
+
+.. code-block:: python
+
+    import oci
+    signer = oci.auth.signers.InstancePrincipalsSecurityTokenSigner()
+    identity = oci.identity.IdentityClient(config={}, signer=signer)
+
 The project is open source and maintained by Oracle Corp. The home page for the project is `here`__.
 
 __ https://docs.oracle.com/en-us/iaas/tools/python/latest/index.html

examples/quickstart_identity.py

@@ -0,0 +1,24 @@
+import oci
+
+
+def main() -> None:
+    config = oci.config.from_file()
+    oci.config.validate_config(config)
+
+    identity = oci.identity.IdentityClient(config)
+    tenancy_id = config["tenancy"]
+
+    compartments = identity.list_compartments(
+        compartment_id=tenancy_id,
+        compartment_id_in_subtree=True,
+        access_level="ACCESSIBLE",
+    ).data
+
+    print("Accessible compartments:")
+    for c in compartments:
+        print(f"- {c.name} ({c.id})")
+
+
+if __name__ == "__main__":
+    main()
+

src/oci/config.py

@@ -107,7 +107,13 @@ def from_file(file_location=DEFAULT_LOCATION, profile_name=DEFAULT_PROFILE):
         raise ConfigFileNotFound("Could not find config file at {}, please follow the instructions in the link to setup the config file https://docs.cloud.oracle.com/en-us/iaas/Content/API/Concepts/sdkconfig.htm".format(expanded_file_location))
 
     if profile_name not in parser:
-        raise ProfileNotFound("Profile '{}' not found in config file {} ".format(profile_name, expanded_file_location) + CONFIG_FILE_DEBUG_INFORMATION_LOG)
+        available_profiles = ", ".join(parser.sections()) if parser.sections() else "(none)"
+        raise ProfileNotFound(
+            "Profile '{}' not found in config file {}. Available profiles: {}. ".format(
+                profile_name, expanded_file_location, available_profiles
+            )
+            + CONFIG_FILE_DEBUG_INFORMATION_LOG
+        )
 
     config = dict(DEFAULT_CONFIG)
     config.update(parser[profile_name])
@@ -136,7 +142,7 @@ def validate_config(config, **kwargs):
         validator_function(config)
         return
 
-    """Raises ValueError if required fields are missing or malformed."""
+    """Raises InvalidConfig if required fields are missing or malformed."""
     errors = {}
     for required_key in REQUIRED:
         fallback_key = REQUIRED_FALLBACKS.get(required_key)

src/oci/exceptions.py

@@ -101,7 +101,24 @@ def __init__(self, errors):
         self.errors = errors
 
     def __str__(self):
-        return str(self.errors)
+        if not isinstance(self.errors, dict):
+            return str(self.errors)
+
+        missing = sorted([k for k, v in self.errors.items() if v == "missing"])
+        malformed = sorted([k for k, v in self.errors.items() if v == "malformed"])
+        other = {k: v for k, v in self.errors.items() if v not in ("missing", "malformed")}
+
+        parts = ["Invalid OCI config."]
+        if missing:
+            parts.append("Missing required keys: {}".format(", ".join(missing)))
+        if malformed:
+            parts.append("Malformed values for keys: {}".format(", ".join(malformed)))
+        if other:
+            parts.append("Other issues: {}".format(other))
+        parts.append(
+            "Config reference: https://docs.oracle.com/en-us/iaas/Content/API/Concepts/sdkconfig.htm"
+        )
+        return " ".join(parts)
 
 
 class InvalidAlloyConfig(ClientError):