Comments migration`:

web/modules/custom/agaric_migration/migrations/agaric_comment.yml

@@ -0,0 +1,81 @@
+id: agaric_comment
+migration_group: agaric
+label: Agaric Comments
+source:
+  plugin: d7_comment
+  constants:
+    entity_type: node
+    comment_type: comment
+process:
+  pid:
+    -
+      plugin: migration_lookup
+      migration: agaric_comment
+      source: pid
+      no_stub: true
+    -
+      plugin: skip_on_empty
+      method: row
+  entity_id:
+    -
+      plugin: migration_lookup
+      migration:
+        - agaric_page
+        - agaric_blog
+      source_ids:
+        agaric_page:
+          - nid
+        agaric_blog:
+          - nid
+      no_stub: true
+    -
+      plugin: skip_on_empty
+      method: row
+  entity_type: 'constants/entity_type'
+  comment_type: 'constants/comment_type'
+  field_name: '@comment_type'
+  subject: subject
+  uid:
+    -
+      plugin: migration_lookup
+      migration: agaric_user
+      source: uid
+      no_stub: true
+    -
+      plugin: default_value
+      default_value: "0"
+      struct: true
+  name: name
+  mail: mail
+  homepage: homepage
+  hostname: hostname
+  created: created
+  changed: changed
+  status: status
+  thread: thread
+  comment_body/format:
+    -
+      plugin: extract
+      source: comment_body
+      index:
+        - 0
+        - format
+    -
+      plugin: static_map
+      map:
+        filtered_html: 'basic_html'
+      bypass: TRUE
+  comment_body/value:
+    -
+        plugin: extract
+        source: comment_body
+        index:
+          - 0
+          - value
+destination:
+  plugin: entity:comment
+  default_bundle: comment
+migration_dependencies:
+  required:
+    - agaric_blog
+    - agaric_page