Migration to remove expectation of demographics.ageRange #2670

data-serving/scripts/setup-db/migrations/20220506100633-remove-age-range.js

@@ -0,0 +1,41 @@
+/*
+ * We need to ensure that ages are bucketed within five-year brackets, except for infants (below 1 year)
+ * to improve the protection against deanonymisation in the case database. A previous migration introduced an
+ * ageBuckets collection which represents an enumeration of the age ranges 0, 1-5, 6-10, 11-15, ..., 116-120.
+ * 
+ * This one removes the now-redundant and inaccurate demographics.ageRange property from the cases collection.
+ * The only information that defines the age for the case should be the buckets.
+ */
+
+const ageRangeSchema ={
+  "bsonType": "object",
+  "additionalProperties": false,
+  "properties": {
+    "start": {
+      "bsonType": "number",
+      "minimum": 0,
+      "maximum": 120
+    },
+    "end": {
+      "bsonType": "number",
+      "minimum": 0,
+      "maximum": 120
+    }
+  }
+};
+
+module.exports = {
+  async up(db, client) {
+    let res = await db.command({listCollections: undefined, filter: {name: 'cases'}});
+    let schema = res.cursor.firstBatch[0].options.validator.$jsonSchema;
+    delete schema.properties.demographics.properties.ageRange;
+    await db.command({ collMod: 'cases', validator:{ $jsonSchema: schema } } );
+  },
+
+  async down(db, client) {
+    let res = await db.command({listCollections: undefined, filter: {name: 'cases'}});
+    let schema = res.cursor.firstBatch[0].options.validator.$jsonSchema;
+    schema.properties.demographics.properties.ageRange = ageRangeSchema;
+    await db.command( { collMod: 'cases', validator:{ $jsonSchema: schema } } );
+  }
+};