♻️ Extract core and utils subpackages

src/utils/patchers.mbt

@@ -0,0 +1,63 @@
+pub type RecordPatch = (@core.Record) -> @core.Record
+
+pub fn identity_patch() -> RecordPatch {
+  fn(rec) { rec }
+}
+
+pub fn set_target(target : String) -> RecordPatch {
+  fn(rec) {
+    rec.with_target(target)
+  }
+}
+
+pub fn prefix_message(prefix : String) -> RecordPatch {
+  fn(rec) {
+    rec.with_message("\{prefix}\{rec.message}")
+  }
+}
+
+pub fn append_fields(extra_fields : Array[@core.Field]) -> RecordPatch {
+  fn(rec) {
+    if extra_fields.length() == 0 {
+      rec
+    } else if rec.fields.length() == 0 {
+      rec.with_fields(extra_fields)
+    } else {
+      rec.with_fields(rec.fields + extra_fields)
+    }
+  }
+}
+
+pub fn redact_field(key : String, placeholder~ : String = "***") -> RecordPatch {
+  fn(rec) {
+    rec.with_fields(rec.fields.map(fn(field) {
+      if field.key == key {
+        field.with_value(placeholder)
+      } else {
+        field
+      }
+    }))
+  }
+}
+
+pub fn redact_fields(keys : Array[String], placeholder~ : String = "***") -> RecordPatch {
+  fn(rec) {
+    rec.with_fields(rec.fields.map(fn(field) {
+      if keys.contains(field.key) {
+        field.with_value(placeholder)
+      } else {
+        field
+      }
+    }))
+  }
+}
+
+pub fn compose_patches(patches : Array[RecordPatch]) -> RecordPatch {
+  fn(rec) {
+    let mut current = rec
+    for patch in patches {
+      current = patch(current)
+    }
+    current
+  }
+}