Add versioned main template upload and separate existence check

- Always upload versioned main template alongside regular main template
- Add separate check for versioned template existence when main template already exists
- Fix 404 error handling for versioned template check using ClientError
- Ensures both idp-main.yaml and idp-main_VERSION.yaml are always available in S3
- Prevents NoSuchKey errors during ACL operations on versioned templates

Author: Taniya Mathur

publish.py

@@ -1492,6 +1492,7 @@ def build_main_template(self, webui_zipfile, components_needing_rebuild):
 
         # Upload main template based on whether build was required
         final_template_key = f"{self.prefix}/{self.main_template}"
+        versioned_template_key = f"{self.prefix}/{self.main_template.replace('.yaml', f'_{self.version}.yaml')}"
         packaged_template_path = ".aws-sam/idp-main.yaml"
 
         if main_needs_build:
@@ -1517,6 +1518,25 @@ def build_main_template(self, webui_zipfile, components_needing_rebuild):
             except Exception as e:
                 self.console.print(f"[red]Failed to upload main template: {e}[/red]")
                 sys.exit(1)
+
+            # Also upload versioned copy
+            self.console.print(
+                f"[cyan]Uploading versioned main template to S3: {versioned_template_key}[/cyan]"
+            )
+            try:
+                self.s3_client.upload_file(
+                    packaged_template_path,
+                    self.bucket,
+                    versioned_template_key,
+                )
+                self.console.print(
+                    "[green]✅ Versioned main template uploaded successfully[/green]"
+                )
+            except Exception as e:
+                self.console.print(
+                    f"[red]Failed to upload versioned main template: {e}[/red]"
+                )
+                sys.exit(1)
         else:
             # Main was not rebuilt, check if template exists in S3
             try:
@@ -1542,6 +1562,19 @@ def build_main_template(self, webui_zipfile, components_needing_rebuild):
                     self.console.print(
                         "[green]✅ Main template uploaded successfully[/green]"
                     )
+
+                    # Also upload versioned copy
+                    self.console.print(
+                        f"[cyan]Uploading versioned main template to S3: {versioned_template_key}[/cyan]"
+                    )
+                    self.s3_client.upload_file(
+                        packaged_template_path,
+                        self.bucket,
+                        versioned_template_key,
+                    )
+                    self.console.print(
+                        "[green]✅ Versioned main template uploaded successfully[/green]"
+                    )
                 except Exception as e:
                     self.console.print(
                         f"[red]Failed to upload main template: {e}[/red]"
@@ -1553,6 +1586,43 @@ def build_main_template(self, webui_zipfile, components_needing_rebuild):
                 )
                 self.console.print("[yellow]Proceeding without upload[/yellow]")
 
+            # Check versioned template separately
+            try:
+                self.s3_client.head_object(
+                    Bucket=self.bucket, Key=versioned_template_key
+                )
+                self.console.print(
+                    "[green]✅ Versioned main template already exists in S3[/green]"
+                )
+            except ClientError as e:
+                if e.response["Error"]["Code"] == "404":
+                    self.console.print(
+                        f"[yellow]Versioned template missing from S3, uploading: {versioned_template_key}[/yellow]"
+                    )
+                    if not os.path.exists(packaged_template_path):
+                        self.console.print(
+                            f"[red]Error: No packaged template to upload at {packaged_template_path}[/red]"
+                        )
+                        sys.exit(1)
+                    try:
+                        self.s3_client.upload_file(
+                            packaged_template_path,
+                            self.bucket,
+                            versioned_template_key,
+                        )
+                        self.console.print(
+                            "[green]✅ Versioned main template uploaded successfully[/green]"
+                        )
+                    except Exception as upload_e:
+                        self.console.print(
+                            f"[red]Failed to upload versioned template: {upload_e}[/red]"
+                        )
+                        sys.exit(1)
+                else:
+                    self.console.print(
+                        f"[yellow]Could not check versioned template existence: {e}[/yellow]"
+                    )
+
         # Validate the template
         template_url = (
             f"https://s3.{self.region}.amazonaws.com/{self.bucket}/{final_template_key}"