Update changelog with dual-pass interp [#173134254]

CHANGELOG.md

@@ -47,7 +47,34 @@ can be found in [Pivotal Documentation](docs.pivotal.io/platform-automation).
   This ensures that commands are not kept in `bash` history.
   The environment variable `OM_PASSWORD` will overwrite the password value in `env.yml`.
 
-## 6.1.3
+## 6.2.0
+
+### Features
+- `interpolate` behavior has been improved
+  in all commands that perform interpolation.
+  All interpolation in `om` is now dual-pass;
+  what would have previously been the final output
+  is interpolated again.
+  This allows the use of mapping-variables,
+  vars that have other vars as their values.
+  For a detailed example, see the new test for this feature,
+  found in `interpolate/interpolate_suite_test.go`.
+  - This is intended to allow the use of vars files
+    to map from automatically generated vars-names,
+    such as those created by `staged-config` and `config-template`.
+  - Also, note that Ops Files are only applied on the first pass,
+    as they're not idempotent in the way that substituion is.
+  - Similarly, the --path argument for `om interpolate` is only applied
+    on the second pass.
+  - We are aware that other CLI tools that use interpolation behavior
+    don't do this, and may not wish to -
+    for example, both `fly` and `bosh` communicate with servers
+    that also understand the ((double-paren)) var syntax,
+    and so possibly have cases for passing these things along unresolved.
+    As far as we know, this is not true of any use of `om`.
+  - We actually can't think of any case where this would be undesirable,
+    _even in the other tools we just mentioned_.
+    If you can, please open an issue!
 
 ### Bug Fixes
 - `configure-product` will no longer assign a new guid for unnamed collections conatin:

interpolate/interpolate_suite_test.go

@@ -163,57 +163,6 @@ var _ = Describe("Execute", func() {
 		})
 	})
 
-	When("always", func() {
-		It("runs the interplation a second time on the output of the first time, without ops files", func() {
-			// The goal here is to allow vars to be used to map multiple variables from some source
-			// into different names.
-			// In our case, the VarsEnv are vars from a secret store,
-			// While vars-files are mappings between those canonical secret store names,
-			// And generated variable names in the template that are based on the yaml structure.
-			// The test setup will attempt to illustrate this situation,
-			// and test that the same thing could be done using flags as the canonical source.
-			// We exclude Ops Files because there should be no need for a second pass,
-			// and they're not guranteed to be idempotent
-			templateContents := `---
-template-keys:
-  key-1: ((template_keys_key_1))
-  key-2: ((template_keys_key_2))
-other-template-keys:
-  other-key-1: ((other_template_keys_other_key_1))
-  other-key-2: ((other_template_keys_other_key_2))
-key-to-be-removed-once: some-value
-`
-			varsFileContents := `---
-template_keys_key_1: ((shared_value_1))
-template_keys_key_2: non-secret-literal-value
-other_template_keys_other_key_1: ((shared_value_1))
-other_template_keys_other_key_2: ((shared_value_2))
-`
-			nonIdempotentOpsFile := `[{type: remove, path: /key-to-be-removed-once}]`
-
-			contents, err := interpolate.Execute(interpolate.Options{
-				TemplateFile: writeFile(templateContents),
-				VarsFiles:    []string{writeFile(varsFileContents)},
-				Vars:         []string{"shared_value_2=our-second-shared-value"},
-				VarsEnvs:     []string{"PREFIX"},
-				EnvironFunc: func() []string {
-					return []string{"PREFIX_shared_value_1=our-first-shared-value"}
-				},
-				OpsFiles: []string{writeFile(nonIdempotentOpsFile)},
-			})
-			Expect(err).ToNot(HaveOccurred())
-			fullyInterpolatedYAML := `---
-template-keys:
-  key-1: our-first-shared-value
-  key-2: non-secret-literal-value
-other-template-keys:
-  other-key-1: our-first-shared-value
-  other-key-2: our-second-shared-value
-`
-			Expect(contents).To(MatchYAML(fullyInterpolatedYAML))
-		})
-	})
-
 	When("vars are specified", func() {
 		It("supports loading individual vars", func() {
 			contents, err := interpolate.Execute(interpolate.Options{
@@ -270,6 +219,55 @@ other-template-keys:
 		})
 		Expect(err).To(MatchError(ContainSubstring("Expected to find variables: username")))
 	})
+
+	It("runs the interplation a second time on the output of the first time, without ops files", func() {
+		// The goal here is to allow vars to be used to map multiple variables from some source
+		// into different names.
+		// In our case, the VarsEnv are vars from a secret store,
+		// While vars-files are mappings between those canonical secret store names,
+		// And generated variable names in the template that are based on the yaml structure.
+		// The test setup will attempt to illustrate this situation,
+		// and test that the same thing could be done using flags as the canonical source.
+		// We exclude Ops Files because there should be no need for a second pass,
+		// and they're not guranteed to be idempotent
+		templateContents := `---
+template-keys:
+  key-1: ((template_keys_key_1))
+  key-2: ((template_keys_key_2))
+other-template-keys:
+  other-key-1: ((other_template_keys_other_key_1))
+  other-key-2: ((other_template_keys_other_key_2))
+key-to-be-removed-once: some-value
+`
+		varsFileContents := `---
+template_keys_key_1: ((shared_value_1))
+template_keys_key_2: non-secret-literal-value
+other_template_keys_other_key_1: ((shared_value_1))
+other_template_keys_other_key_2: ((shared_value_2))
+`
+		nonIdempotentOpsFile := `[{type: remove, path: /key-to-be-removed-once}]`
+
+		contents, err := interpolate.Execute(interpolate.Options{
+			TemplateFile: writeFile(templateContents),
+			VarsFiles:    []string{writeFile(varsFileContents)},
+			Vars:         []string{"shared_value_2=our-second-shared-value"},
+			VarsEnvs:     []string{"PREFIX"},
+			EnvironFunc: func() []string {
+				return []string{"PREFIX_shared_value_1=our-first-shared-value"}
+			},
+			OpsFiles: []string{writeFile(nonIdempotentOpsFile)},
+		})
+		Expect(err).ToNot(HaveOccurred())
+		fullyInterpolatedYAML := `---
+template-keys:
+  key-1: our-first-shared-value
+  key-2: non-secret-literal-value
+other-template-keys:
+  other-key-1: our-first-shared-value
+  other-key-2: our-second-shared-value
+`
+		Expect(contents).To(MatchYAML(fullyInterpolatedYAML))
+	})
 })
 
 func writeFile(contents string) string {