feat(inflection): add dns_1123() for Kubernetes DNS-1123 label normalization

packages/inflection/Makefile

@@ -1,5 +1,5 @@
 EXTENSION = pgpm-inflection
-DATA = sql/pgpm-inflection--0.15.5.sql
+DATA = sql/pgpm-inflection--0.30.0.sql
 
 PG_CONFIG = pg_config
 PGXS := $(shell $(PG_CONFIG) --pgxs)

packages/inflection/__tests__/inflection.test.ts

@@ -221,4 +221,34 @@ describe('inflection', () => {
       { name: 'information', result: 'information' }
     ]
   );
+
+  cases(
+    'dns_1123',
+    async (opts: { name: string; result: string }) => {
+      const { dns_1123 } = await pg.one(
+        'SELECT * FROM inflection.dns_1123($1)',
+        [opts.name]
+      );
+      expect(dns_1123).toEqual(opts.result);
+    },
+    [
+      { name: 'api', result: 'api' },
+      { name: 'MyService', result: 'myservice' },
+      { name: 'my_service', result: 'my-service' },
+      { name: 'org:api', result: 'org--api' },
+      { name: 'Hello, World!', result: 'helloworld' },
+      { name: '__leading', result: 'leading' },
+      { name: 'trailing__', result: 'trailing' },
+      { name: '---', result: '' },
+      {
+        name: 'a'.repeat(80),
+        result: 'a'.repeat(63)
+      },
+      {
+        // truncation lands on a '-'; trailing non-alphanumerics are dropped
+        name: `${'a'.repeat(62)}-bcd`,
+        result: 'a'.repeat(62)
+      }
+    ]
+  );
 });

packages/inflection/deploy/schemas/inflection/procedures/dns_1123.sql

@@ -0,0 +1,64 @@
+-- Deploy schemas/inflection/procedures/dns_1123 to pg
+
+-- requires: schemas/inflection/schema
+
+-- Normalizes a value into a Kubernetes DNS-1123 label (RFC 1123):
+-- lowercase alphanumerics and '-', at most 63 characters, and no leading or
+-- trailing '-'. Used to derive Knative/K8s object names from arbitrary slugs.
+
+BEGIN;
+
+CREATE FUNCTION inflection.dns_1123 (value text)
+  RETURNS text
+  AS $$
+  WITH lowercased AS (
+    SELECT
+      lower(value) AS value
+),
+-- ':' delimits namespaced identifiers; map to '--' so the boundary survives
+namespaced AS (
+  SELECT
+    replace(value, ':', '--') AS value
+FROM
+  lowercased
+),
+hyphenated AS (
+  SELECT
+    replace(value, '_', '-') AS value
+FROM
+  namespaced
+),
+stripped AS (
+  SELECT
+    regexp_replace(value, '[^a-z0-9-]', '', 'g') AS value
+FROM
+  hyphenated
+),
+trimmed AS (
+  SELECT
+    regexp_replace(value, '^-+|-+$', '', 'g') AS value
+FROM
+  stripped
+),
+truncated AS (
+  SELECT
+    "left"(value, 63) AS value
+FROM
+  trimmed
+),
+-- truncation can leave a dangling '-'; drop any trailing non-alphanumerics
+final AS (
+  SELECT
+    regexp_replace(value, '[^a-z0-9]+$', '') AS value
+FROM
+  truncated
+)
+SELECT
+  value
+FROM
+  final;
+$$
+LANGUAGE SQL
+STRICT IMMUTABLE;
+
+COMMIT;

packages/inflection/pgpm-inflection.control

@@ -1,6 +1,6 @@
 # pgpm-inflection extension
 comment = 'pgpm-inflection extension'
-default_version = '0.15.5'
+default_version = '0.30.0'
 module_pathname = '$libdir/pgpm-inflection'
 requires = 'plpgsql,unaccent,pgpm-verify'
 relocatable = false

packages/inflection/pgpm.plan

@@ -1,7 +1,7 @@
 %syntax-version=1.0.0
 %project=pgpm-inflection
 %uri=pgpm-inflection
-  
+
 schemas/inflection/schema 2017-08-11T08:11:51Z skitch <skitch@5b0c196eeb62> # add schemas/inflection/schema
 schemas/inflection/procedures/no_consecutive_caps [schemas/inflection/schema] 2017-08-11T08:11:51Z skitch <skitch@5b0c196eeb62> # add schemas/inflection/procedures/no_consecutive_caps
 schemas/inflection/procedures/pg_slugify [schemas/inflection/schema schemas/inflection/procedures/no_consecutive_caps] 2017-08-11T08:11:51Z skitch <skitch@5b0c196eeb62> # add schemas/inflection/procedures/pg_slugify
@@ -18,3 +18,4 @@ schemas/inflection/procedures/singular [schemas/inflection/schema schemas/inflec
 schemas/inflection/procedures/slugify [schemas/inflection/schema] 2017-08-11T08:11:51Z skitch <skitch@5b0c196eeb62> # add schemas/inflection/procedures/slugify
 schemas/inflection/tables/inflection_rules/fixtures/1589249334312_fixture [schemas/inflection/schema schemas/inflection/tables/inflection_rules/table] 2017-08-11T08:11:51Z skitch <skitch@5b0c196eeb62> # add schemas/inflection/tables/inflection_rules/fixtures/1589249334312_fixture
 schemas/inflection/tables/inflection_rules/indexes/inflection_rules_type_idx [schemas/inflection/schema schemas/inflection/tables/inflection_rules/table] 2017-08-11T08:11:51Z skitch <skitch@5b0c196eeb62> # add schemas/inflection/tables/inflection_rules/indexes/inflection_rules_type_idx
+schemas/inflection/procedures/dns_1123 [schemas/inflection/schema] 2026-07-11T22:14:14Z constructive <constructive@5b0c196eeb62> # Kubernetes DNS-1123 label normalization

packages/inflection/revert/schemas/inflection/procedures/dns_1123.sql

@@ -0,0 +1,7 @@
+-- Revert schemas/inflection/procedures/dns_1123 from pg
+
+BEGIN;
+
+DROP FUNCTION inflection.dns_1123(text);
+
+COMMIT;