feat: Allow escaping dollar in Envsubst (argoproj#7961)

* feat: allow escaping dollar in Envsubst Signed-off-by: Thomas Dy <[email protected]> * docs: add variable escape documentation Signed-off-by: Thomas Dy <[email protected]>
softrams · Jan 12, 2022 · c8bcabe · c8bcabe
1 parent 4b5df69
commit c8bcabe
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Showing 3 changed files with 26 additions and 2 deletions.
diff --git a/docs/user-guide/build-environment.md b/docs/user-guide/build-environment.md
@@ -11,4 +11,14 @@
 * `ARGOCD_APP_SOURCE_REPO_URL` the repo's URL
 * `ARGOCD_APP_SOURCE_TARGET_REVISION` - the target revision from the spec, e.g. `master`.
 * `KUBE_VERSION` - the version of kubernetes
-* `KUBE_API_VERSIONS` = the version of kubernetes API
+* `KUBE_API_VERSIONS` = the version of kubernetes API
+
+In case you don't want a variable to be interpolated, `$` can be escaped via `$$`.
+
+```
+command:
+  - sh
+  - -c
+  - |
+    echo $$FOO
+```
diff --git a/pkg/apis/application/v1alpha1/types.go b/pkg/apis/application/v1alpha1/types.go
@@ -141,7 +141,12 @@ func (e Env) Envsubst(s string) string {
 		valByEnv[item.Name] = item.Value
 	}
 	return os.Expand(s, func(s string) string {
-		return valByEnv[s]
+		// allow escaping $ with $$
+		if s == "$" {
+			return "$"
+		} else {
+			return valByEnv[s]
+		}
 	})
 }
 

diff --git a/pkg/apis/application/v1alpha1/types_test.go b/pkg/apis/application/v1alpha1/types_test.go
@@ -2587,3 +2587,12 @@ func Test_validatePolicy_ValidResource(t *testing.T) {
 	err = validatePolicy("some-project", "org-admin", "p, proj:some-project:org-admin, clusters, *, some-project/*, allow")
 	assert.NoError(t, err)
 }
+
+func TestEnvsubst(t *testing.T) {
+	env := Env{
+		&EnvEntry{"foo", "bar"},
+	}
+
+	assert.Equal(t, "bar", env.Envsubst("$foo"))
+	assert.Equal(t, "$foo", env.Envsubst("$$foo"))
+}