Update output examples

README.md

@@ -8,6 +8,71 @@ Error management for archival workflows
 
 [docs-1]: https://pkg.go.dev/github.com/ocfl-archive/error/pkg/error#NewFactory
 
+### Example output
+
+Given an example error described in YAML and registered with the error factory
+on startup:
+
+```yaml
+- id: "GOCFL::1"
+  type: "FileSystem"
+  weight: 20
+  message: "cannot access filesystem"
+```
+
+Output is structured as shown below.
+
+#### Via the default logger
+
+<!--markdownlint-disable-->
+
+```log
+2024/11/22 13:07:46 [FileSystem] #GOCFL::1 (/tmp/logtest/logtest.go:41): cannot access filesystem - (add)ing to GOCFL archive
+```
+
+<!--markdownlint-enable-->
+
+#### Via zerolog
+
+```json
+{
+  "level": "error",
+  "archive": {
+    "id": "GOCFL::1",
+    "type": "FileSystem",
+    "weight": 20,
+    "source_file": "/tmp/logtest/logtest.go:39",
+    "source_func": "main.main",
+    "message": "cannot access filesystem",
+    "additional": "(add)ing to GOCFL archive",
+    "error_data": {
+      "message": "disk is readonly",
+      "stack": ""
+    }
+  },
+  "time": 1732277218,
+  "message": "An error occurred"
+}
+```
+
+#### As JSON
+
+```json
+{
+  "id": "GOCFL::1",
+  "type": "FileSystem",
+  "weight": 20,
+  "source_file": "/tmp/logtest/logtest.go:36",
+  "source_func": "main.main",
+  "message": "cannot access filesystem",
+  "additional": "(add)ing to GOCFL archive",
+  "error_data": {
+    "message": "disk is readonly",
+    "stack": ""
+  }
+}
+```
+
 ## Developer guide
 
 ### justfile