Add secondary_profiles to profile.py (#11308)

* Add secondary_profiles to profile.py

* Add more tests for edge cases

* Add changie

* Allow inferring target name and add tests for the same

* Incorporate review feedback

* remove unnecessary nesting

* Use typing_extensions.Self

* use quoted type again

* address pr comments round 2

Author: aranke

Diff for: .changes/unreleased/Under the Hood-20250214-123853.yaml

@@ -0,0 +1,6 @@
+kind: Under the Hood
+body: Add secondary profiles to profile.py
+time: 2025-02-14T12:38:53.964266Z
+custom:
+    Author: aranke
+    Issue: XPLAT-241

Diff for: core/dbt/config/profile.py

@@ -60,6 +60,7 @@ class Profile(HasCredentials):
     credentials: Credentials
     profile_env_vars: Dict[str, Any]
     log_cache_events: bool
+    secondary_profiles: Dict[str, "Profile"]
 
     def __init__(
         self,
@@ -79,6 +80,7 @@ def __init__(
         self.log_cache_events = (
             get_flags().LOG_CACHE_EVENTS
         )  # never available on init, set for adapter instantiation via AdapterRequiredConfig
+        self.secondary_profiles = {}
 
     def to_profile_info(self, serialize_credentials: bool = False) -> Dict[str, Any]:
         """Unlike to_project_config, this dict is not a mirror of any existing
@@ -257,6 +259,7 @@ def render_profile(
         profile_name: str,
         target_override: Optional[str],
         renderer: ProfileRenderer,
+        is_secondary: bool = False,
     ) -> Tuple[str, Dict[str, Any]]:
         """This is a containment zone for the hateful way we're rendering
         profiles.
@@ -273,6 +276,12 @@ def render_profile(
         elif "target" in raw_profile:
             # render the target if it was parsed from yaml
             target_name = renderer.render_value(raw_profile["target"])
+        elif is_secondary and len(raw_profile.get("outputs", [])) == 1:
+            # if we only have one target, we can infer the target name
+            # currently, this is only used for secondary profiles
+            target_name = next(iter(raw_profile["outputs"]))
+            # the event name is slightly misleading, but the message indicates that we inferred the target name for a profile
+            fire_event(MissingProfileTarget(profile_name=profile_name, target_name=target_name))
         else:
             target_name = "default"
             fire_event(MissingProfileTarget(profile_name=profile_name, target_name=target_name))
@@ -293,6 +302,7 @@ def from_raw_profile_info(
         renderer: ProfileRenderer,
         target_override: Optional[str] = None,
         threads_override: Optional[int] = None,
+        is_secondary: bool = False,
     ) -> "Profile":
         """Create a profile from its raw profile information.
 
@@ -312,9 +322,14 @@ def from_raw_profile_info(
         """
         # TODO: should it be, and the values coerced to bool?
         target_name, profile_data = cls.render_profile(
-            raw_profile, profile_name, target_override, renderer
+            raw_profile, profile_name, target_override, renderer, is_secondary=is_secondary
         )
 
+        if is_secondary and "secondary_profiles" in profile_data:
+            raise DbtProfileError(
+                f"Secondary profile '{profile_name}' cannot have nested secondary profiles"
+            )
+
         # valid connections never include the number of threads, but it's
         # stored on a per-connection level in the raw configs
         threads = profile_data.pop("threads", DEFAULT_THREADS)
@@ -325,13 +340,31 @@ def from_raw_profile_info(
             profile_data, profile_name, target_name
         )
 
-        return cls.from_credentials(
+        profile = cls.from_credentials(
             credentials=credentials,
             profile_name=profile_name,
             target_name=target_name,
             threads=threads,
         )
 
+        for p in profile_data.pop("secondary_profiles", []):
+            for secondary_profile_name, secondary_raw_profile in p.items():
+                if secondary_profile_name in profile.secondary_profiles:
+                    raise DbtProfileError(
+                        f"Secondary profile '{secondary_profile_name}' is already defined"
+                    )
+
+                profile.secondary_profiles[secondary_profile_name] = cls.from_raw_profile_info(
+                    secondary_raw_profile,
+                    secondary_profile_name,
+                    renderer,
+                    target_override=target_override,
+                    threads_override=threads_override,
+                    is_secondary=True,
+                )
+
+        return profile
+
     @classmethod
     def from_raw_profiles(
         cls,

Diff for: core/dbt/config/runtime.py

@@ -184,6 +184,7 @@ def from_parts(
             project_env_vars=project.project_env_vars,
             restrict_access=project.restrict_access,
             profile_env_vars=profile.profile_env_vars,
+            secondary_profiles=profile.secondary_profiles,
             profile_name=profile.profile_name,
             target_name=profile.target_name,
             threads=profile.threads,