update docs

docs/docs/config.md

@@ -43,8 +43,11 @@ Tanka's behavior can be customized per Environment using a file called `spec.jso
     "diffStrategy": "[native, subset]" | default = "auto",
 
     // Whether to add a "tanka.dev/environment" label to each created resource.
-    // Required for garbage collection ("tk prune").
     "injectLabels": <boolean> | default = false
+
+    // Whether to add a "tanka.dev/prune-mark" label to each created resource.
+    // Required for garbage collection ("tk prune").
+    "pruneMark": <boolean> | default = false
   }
 }
 ```

docs/docs/garbage-collection.md

@@ -11,9 +11,9 @@ from Jsonnet.
 
 > **Note:** This feature is **experimental**. Please report problems at https://github.com/grafana/tanka/issues.
 
-To accomplish this, it appends the `tanka.dev/environment: <name>` label to each created
-resource. This is used to identify those which are missing from the local state in the
-future.
+To accomplish this, it appends the `tanka.dev/prune-mark: sha256(relative_path)`
+label to each created resource. This is used to identify those which are missing
+from the local state in the future.
 
 Because the label causes a `diff` for every single object in your cluster and
 not everybody wants this, it needs to be explicitly enabled. To do so, add the
@@ -22,7 +22,7 @@ following field to your `spec.json`:
 ```diff
 {
   "spec": {
-+    "injectLabels": true,
++    "pruneMark": true,
   }
 }
 ```

pkg/tanka/prune.go

@@ -18,7 +18,7 @@ type PruneOpts struct {
 }
 
 // Prune deletes all resources from the cluster, that are no longer present in
-// Jsonnet. It uses the `tanka.dev/environment` label to identify those.
+// Jsonnet. It uses the `tanka.dev/prune-mark` label to identify those.
 func Prune(baseDir string, opts PruneOpts) error {
 	// parse jsonnet, init k8s client
 	p, err := load(baseDir, opts.Opts)