orchestration: support stack template composition

dverbeir · dverbeir · commit 5a0f2acd01f6 · 2023-08-29T18:20:15.000+02:00
In order for composable stack templates to work, the following changes
are needed:

* a child template URL must be interpreted as relative to its parent
  template, not to the base URL
* the child templates and 'get_file' of child templates must also be
  included in the stack create request
* the references within child templates (to other templates or files)
  must be resolved so the correct URLs are provided, matching the files
  provided in the OS stack create request, just like is done for the
  top-level template.

Signed-off-by: David Verbeiren &lt;david.verbeiren@tessares.net&gt;
diff --git a/openstack/orchestration/v1/stacks/template.go b/openstack/orchestration/v1/stacks/template.go
@@ -2,6 +2,7 @@ package stacks
 
 import (
 	"fmt"
+	"path/filepath"
 	"reflect"
 	"strings"
 
@@ -76,12 +77,12 @@ func (t *Template) getFileContents(te interface{}, ignoreIf igFunc, recurse bool
 
 				// initialize child template
 
-				// get the base location of the child template
-				baseURL, err := gophercloud.NormalizePathURL(t.baseURL, value)
-				if err != nil {
-					return err
+				// get the base location of the child template. Child path is relative
+				// to its parent location so that templates can be composed
+				if t.URL != "" {
+					childTemplate.baseURL = filepath.Dir(t.URL)
 				}
-				childTemplate.baseURL = baseURL
+				childTemplate.URL = value
 				childTemplate.client = t.client
 
 				// fetch the contents of the child template
@@ -98,14 +99,21 @@ func (t *Template) getFileContents(te interface{}, ignoreIf igFunc, recurse bool
 							if err := childTemplate.getFileContents(childTemplate.Parsed, ignoreIf, recurse); err != nil {
 								return err
 							}
+							childTemplate.fixFileRefs()
 						}
 					}
+					// If it doesn't parse as a template, it a 'get_file'
 				}
+
 				// update parent template with current child templates' content.
 				// At this point, the child template has been parsed recursively.
 				t.fileMaps[value] = childTemplate.URL
 				t.Files[childTemplate.URL] = string(childTemplate.Bin)
 
+				// Also add child templates' own children (templates or get_file)!
+				for k, v := range childTemplate.Files {
+					t.Files[k] = v
+				}
 			}
 		}
 		return nil
