Add Habit Tracker example: Next.js, Drizzle ORM and ClickHouse Managed Postgres

.github/workflows/habit-tracker.yml

@@ -0,0 +1,35 @@
+name: Habit Tracker checks
+
+on:
+  pull_request:
+    paths:
+      - 'applications/habit-tracker/**'
+      - '.github/workflows/habit-tracker.yml'
+  push:
+    branches: [main]
+    paths:
+      - 'applications/habit-tracker/**'
+      - '.github/workflows/habit-tracker.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: applications/habit-tracker
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
+        with:
+          node-version: 24.22.1
+          cache: npm
+          cache-dependency-path: applications/habit-tracker/package-lock.json
+      - run: npm ci --ignore-scripts
+      - run: npm test
+      - run: npm run build
+
+# Integration tests need a Postgres database; see the README.

README.md

@@ -76,6 +76,7 @@ ClickHouse ships official client libraries for [C# / .NET](https://clickhouse.co
 - [Shortwave link shortener](./applications/shortwave/README.md): Build and deploy a link shortener using ClickHouse Managed Postgres for application data, ClickPipes for metadata sync, and ClickHouse for click analytics.
 - [Feature Request Board](./applications/feature-request-board/README.md): Build a Next.js and Prisma board with Clerk sign-in, request ownership, and one vote per user on ClickHouse Managed Postgres.
 - [Workshop Booking API](./applications/workshop-booking/README.md): Build a FastAPI and SQLAlchemy application on ClickHouse Managed Postgres with transactional seat allocation, cancellation, and safe retries.
+- [Habit Tracker](./applications/habit-tracker/README.md): Build a Next.js and Drizzle ORM habit tracker on ClickHouse Managed Postgres with one check-in per habit per day and streaks computed in SQL.
 - [Postgres-to-ClickHouse data modeling](./postgresql-clickhouse-data-modeling/README.md): Replicate a tiny fixture from PostgreSQL to ClickHouse with PeerDB, then verify inserts, updates, and deletes. Follow the separate ClickHouse Managed Postgres and ClickPipes walkthrough for ClickHouse Cloud; a larger Stack Overflow import is optional.
 
 ### ClickStack: logs, metrics, traces, and session replay

applications/habit-tracker/.env.example

@@ -0,0 +1,8 @@
+# Runtime connection as the least-privilege app role. No query parameters:
+# TLS is configured from PGSSLROOTCERT in src/db.ts.
+DATABASE_URL=postgres://habit_tracker_app:REPLACE_ME@REPLACE_HOST:5432/postgres
+# CA certificate from `clickhousectl cloud postgres certs get`. Leave unset for
+# local Postgres without TLS.
+PGSSLROOTCERT=/absolute/path/to/.deployment/ca.pem
+# "Today" is computed in this IANA time zone. Defaults to UTC.
+APP_TIME_ZONE=UTC

applications/habit-tracker/.gitignore

@@ -0,0 +1,9 @@
+node_modules/
+.next/
+next-env.d.ts
+*.tsbuildinfo
+.env*
+!.env.example
+.deployment/
+.clickhouse/
+.DS_Store

applications/habit-tracker/drizzle.config.ts

@@ -0,0 +1,22 @@
+import { defineConfig } from "drizzle-kit";
+import { tlsOptions } from "./src/db";
+
+// drizzle-kit opens its own connection, so it needs the same TLS settings as src/db.ts.
+const url = new URL(
+  process.env.DATABASE_URL ?? "postgres://localhost:5432/postgres",
+);
+
+export default defineConfig({
+  dialect: "postgresql",
+  schema: "./src/schema.ts",
+  out: "./drizzle",
+  schemaFilter: ["habit_tracker"],
+  dbCredentials: {
+    host: url.hostname,
+    port: Number(url.port || 5432),
+    user: decodeURIComponent(url.username),
+    password: decodeURIComponent(url.password),
+    database: url.pathname.slice(1) || "postgres",
+    ssl: tlsOptions(url.href, process.env.PGSSLROOTCERT),
+  },
+});

applications/habit-tracker/drizzle/0000_init.sql

@@ -0,0 +1,26 @@
+CREATE SCHEMA "habit_tracker";
+--> statement-breakpoint
+CREATE TABLE "habit_tracker"."check_ins" (
+	"habit_id" integer NOT NULL,
+	"day" date NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	CONSTRAINT "check_ins_habit_id_day_pk" PRIMARY KEY("habit_id","day")
+);
+--> statement-breakpoint
+CREATE TABLE "habit_tracker"."habits" (
+	"id" integer PRIMARY KEY GENERATED ALWAYS AS IDENTITY (sequence name "habit_tracker"."habits_id_seq" INCREMENT BY 1 MINVALUE 1 MAXVALUE 2147483647 START WITH 1 CACHE 1),
+	"user_id" integer NOT NULL,
+	"name" text NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"archived_at" timestamp with time zone,
+	CONSTRAINT "habits_name_length" CHECK (char_length("habit_tracker"."habits"."name") between 1 and 60)
+);
+--> statement-breakpoint
+CREATE TABLE "habit_tracker"."users" (
+	"id" integer PRIMARY KEY GENERATED ALWAYS AS IDENTITY (sequence name "habit_tracker"."users_id_seq" INCREMENT BY 1 MINVALUE 1 MAXVALUE 2147483647 START WITH 1 CACHE 1),
+	"name" text NOT NULL
+);
+--> statement-breakpoint
+ALTER TABLE "habit_tracker"."check_ins" ADD CONSTRAINT "check_ins_habit_id_habits_id_fk" FOREIGN KEY ("habit_id") REFERENCES "habit_tracker"."habits"("id") ON DELETE cascade ON UPDATE no action;--> statement-breakpoint
+ALTER TABLE "habit_tracker"."habits" ADD CONSTRAINT "habits_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "habit_tracker"."users"("id") ON DELETE no action ON UPDATE no action;--> statement-breakpoint
+CREATE INDEX "habits_active_by_user" ON "habit_tracker"."habits" USING btree ("user_id") WHERE "habit_tracker"."habits"."archived_at" is null;

applications/habit-tracker/drizzle/meta/0000_snapshot.json

@@ -0,0 +1,204 @@
+{
+  "id": "47862eeb-58a6-48bd-8151-6b46655f4082",
+  "prevId": "00000000-0000-0000-0000-000000000000",
+  "version": "7",
+  "dialect": "postgresql",
+  "tables": {
+    "habit_tracker.check_ins": {
+      "name": "check_ins",
+      "schema": "habit_tracker",
+      "columns": {
+        "habit_id": {
+          "name": "habit_id",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "day": {
+          "name": "day",
+          "type": "date",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {
+        "check_ins_habit_id_habits_id_fk": {
+          "name": "check_ins_habit_id_habits_id_fk",
+          "tableFrom": "check_ins",
+          "tableTo": "habits",
+          "schemaTo": "habit_tracker",
+          "columnsFrom": [
+            "habit_id"
+          ],
+          "columnsTo": [
+            "id"
+          ],
+          "onDelete": "cascade",
+          "onUpdate": "no action"
+        }
+      },
+      "compositePrimaryKeys": {
+        "check_ins_habit_id_day_pk": {
+          "name": "check_ins_habit_id_day_pk",
+          "columns": [
+            "habit_id",
+            "day"
+          ]
+        }
+      },
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "habit_tracker.habits": {
+      "name": "habits",
+      "schema": "habit_tracker",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "integer",
+          "primaryKey": true,
+          "notNull": true,
+          "identity": {
+            "type": "always",
+            "name": "habits_id_seq",
+            "schema": "habit_tracker",
+            "increment": "1",
+            "startWith": "1",
+            "minValue": "1",
+            "maxValue": "2147483647",
+            "cache": "1",
+            "cycle": false
+          }
+        },
+        "user_id": {
+          "name": "user_id",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "name": {
+          "name": "name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "archived_at": {
+          "name": "archived_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": false
+        }
+      },
+      "indexes": {
+        "habits_active_by_user": {
+          "name": "habits_active_by_user",
+          "columns": [
+            {
+              "expression": "user_id",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            }
+          ],
+          "isUnique": false,
+          "where": "\"habit_tracker\".\"habits\".\"archived_at\" is null",
+          "concurrently": false,
+          "method": "btree",
+          "with": {}
+        }
+      },
+      "foreignKeys": {
+        "habits_user_id_users_id_fk": {
+          "name": "habits_user_id_users_id_fk",
+          "tableFrom": "habits",
+          "tableTo": "users",
+          "schemaTo": "habit_tracker",
+          "columnsFrom": [
+            "user_id"
+          ],
+          "columnsTo": [
+            "id"
+          ],
+          "onDelete": "no action",
+          "onUpdate": "no action"
+        }
+      },
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {
+        "habits_name_length": {
+          "name": "habits_name_length",
+          "value": "char_length(\"habit_tracker\".\"habits\".\"name\") between 1 and 60"
+        }
+      },
+      "isRLSEnabled": false
+    },
+    "habit_tracker.users": {
+      "name": "users",
+      "schema": "habit_tracker",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "integer",
+          "primaryKey": true,
+          "notNull": true,
+          "identity": {
+            "type": "always",
+            "name": "users_id_seq",
+            "schema": "habit_tracker",
+            "increment": "1",
+            "startWith": "1",
+            "minValue": "1",
+            "maxValue": "2147483647",
+            "cache": "1",
+            "cycle": false
+          }
+        },
+        "name": {
+          "name": "name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    }
+  },
+  "enums": {},
+  "schemas": {
+    "habit_tracker": "habit_tracker"
+  },
+  "sequences": {},
+  "roles": {},
+  "policies": {},
+  "views": {},
+  "_meta": {
+    "columns": {},
+    "schemas": {},
+    "tables": {}
+  }
+}

applications/habit-tracker/drizzle/meta/_journal.json

@@ -0,0 +1,13 @@
+{
+  "version": "7",
+  "dialect": "postgresql",
+  "entries": [
+    {
+      "idx": 0,
+      "version": "7",
+      "when": 1792587155318,
+      "tag": "0000_init",
+      "breakpoints": true
+    }
+  ]
+}

applications/habit-tracker/next.config.ts

@@ -0,0 +1,7 @@
+import type { NextConfig } from "next";
+
+const config: NextConfig = {
+  poweredByHeader: false,
+};
+
+export default config;