feat: add R related variants for custom sessions (#1219)

Author: SalimKayal

components/renku_data_services/session/core.py

@@ -66,11 +66,15 @@ def validate_unsaved_build_parameters(
 
     platforms = __validate_build_parameters_platforms(environment.platforms)
 
+    builder_variant, frontend_variant = __validate_builder_frontend_combination(
+        environment.builder_variant, environment.frontend_variant
+    )
+
     return models.UnsavedBuildParameters(
         repository=environment.repository,
         platforms=platforms,
-        builder_variant=environment.builder_variant,
-        frontend_variant=environment.frontend_variant,
+        builder_variant=builder_variant,
+        frontend_variant=frontend_variant,
         repository_revision=environment.repository_revision if environment.repository_revision else None,
         context_dir=environment.context_dir if environment.context_dir else None,
     )
@@ -97,11 +101,20 @@ def validate_build_parameters_patch(environment: apispec.BuildParametersPatch) -
     if environment.platforms is not None:
         platforms = __validate_build_parameters_platforms(environment.platforms)
 
+    builder_variant: str | None = None
+    frontend_variant: str | None = None
+    if environment.builder_variant is not None and environment.frontend_variant is not None:
+        builder_variant, frontend_variant = __validate_builder_frontend_combination(
+            environment.builder_variant, environment.frontend_variant
+        )
+    else:
+        builder_variant, frontend_variant = environment.builder_variant, environment.frontend_variant
+
     return models.BuildParametersPatch(
         repository=environment.repository,
         platforms=platforms,
-        builder_variant=environment.builder_variant,
-        frontend_variant=environment.frontend_variant,
+        builder_variant=builder_variant,
+        frontend_variant=frontend_variant,
         repository_revision=environment.repository_revision,
         context_dir=environment.context_dir,
     )
@@ -374,3 +387,14 @@ def __validate_build_parameters_platforms(platforms: list[apispec.BuildPlatform]
                 )
             )
     return [models.Platform(item) for item in platforms_str_list]
+
+
+def __validate_builder_frontend_combination(builder_variant: str, frontend_variant: str) -> tuple[str, str]:
+    """Validate the combination of builder and frontend variants."""
+    combo = (models.BuilderVariant(builder_variant), models.FrontendVariant(frontend_variant))
+    if combo not in models.VALID_BUILDER_FRONTEND_COMBINATIONS:
+        raise errors.ValidationError(
+            message=f"Invalid combination: builder '{builder_variant}' is not compatible with"
+            "frontend '{frontend_variant}'"
+        )
+    return builder_variant, frontend_variant

components/renku_data_services/session/models.py

@@ -51,6 +51,7 @@ class BuilderVariant(StrEnum):
     """The type of environment builder."""
 
     python = "python"
+    r = "r"
 
 
 class FrontendVariant(StrEnum):
@@ -59,6 +60,15 @@ class FrontendVariant(StrEnum):
     vscodium = "vscodium"
     jupyterlab = "jupyterlab"
     ttyd = "ttyd"
+    rstudio = "rstudio"
+
+
+VALID_BUILDER_FRONTEND_COMBINATIONS: typing.Final[set[tuple[BuilderVariant, FrontendVariant]]] = {
+    (BuilderVariant.r, FrontendVariant.rstudio),
+    (BuilderVariant.python, FrontendVariant.vscodium),
+    (BuilderVariant.python, FrontendVariant.jupyterlab),
+    (BuilderVariant.python, FrontendVariant.ttyd),
+}
 
 
 @dataclass(kw_only=True, frozen=True, eq=True)