feat: Add email-based workshop identifier and configure nbstripout

Implement deterministic resource naming using email-based identifiers
and configure automatic output cell stripping for notebooks.

Changes:
- Add interactive workshop identifier setup in 01_preflight.ipynb
  - Prompts student for email address
  - Hashes email (MD5, 6 chars) for privacy and determinism
  - Creates identifier: -workshop-YYYYMMDD-<hash>
  - Saves to artifacts/workshop_identifier.json

- Update 02_terraform_apply.ipynb to use identifier
  - Loads identifier from artifacts file
  - Passes identifier to Terraform via -var identifier=...
  - Removes incorrect cluster_name variable (not a Terraform input)
  - Computes expected cluster name for validation

- Update 01_preflight.ipynb cluster check
  - Uses identifier to compute cluster name
  - Falls back to CLUSTER_NAME env var if identifier not set

- Configure nbstripout for automatic output cell stripping
  - Add .gitattributes with *.ipynb filter=nbstripout
  - Ensures output cells are never committed

Benefits:
- No additional environment variables required
- Deterministic identifiers (same email = same identifier)
- Idempotent deployments (safe to re-run)
- Unique per student
- Automatic output cell management

.gitattributes

@@ -0,0 +1,3 @@
+# Automatically strip output cells from Jupyter notebooks before committing
+*.ipynb filter=nbstripout
+

env-samples/workshop.env.example

@@ -15,7 +15,7 @@ AWS_REGION="us-east-1"
 AWS_ACCOUNT_ID=""
 
 # Naming (used by notebooks for display + validation)
-CLUSTER_NAME="langsmith-workshop"
+#CLUSTER_NAME=""
 
 # Local repo paths (absolute is safest)
 TERRAFORM_REPO_DIR="$HOME/src/langchain-ai/terraform"

notebooks/module-1/01_preflight.ipynb

@@ -129,6 +129,77 @@
     "        print(f\"💡 Tip: Set {account_var} in your .env file to add a guardrail against wrong account deployments\")\n"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Workshop Identifier Setup\n",
+    "\n",
+    "To ensure unique resource names and enable idempotent deployments, we need a unique identifier for your workshop deployment. This identifier will be used for all Terraform resources.\n",
+    "\n",
+    "**We'll use your email address** (hashed for privacy) to create a deterministic identifier that:\n",
+    "- ✅ Stays the same across notebook runs (idempotent)\n",
+    "- ✅ Is unique per student\n",
+    "- ✅ Works with the date-based prefix for resource naming\n",
+    "\n",
+    "Enter your email address below. It will be hashed and used to generate your unique workshop identifier.\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Generate deterministic workshop identifier from email\n",
+    "import hashlib\n",
+    "import json\n",
+    "from datetime import date\n",
+    "from pathlib import Path\n",
+    "\n",
+    "print(\"### Workshop Identifier Setup\\n\")\n",
+    "print(\"Enter your email address to generate a unique, deterministic identifier for your deployment.\\n\")\n",
+    "print(\"This identifier will be used for all Terraform resources and ensures:\")\n",
+    "print(\"  - Same email = same identifier (idempotent)\")\n",
+    "print(\"  - Different emails = different identifiers (unique)\")\n",
+    "print(\"  - No additional environment variables needed\\n\")\n",
+    "\n",
+    "# Prompt for email (using input() - works in Jupyter)\n",
+    "email = input(\"Enter your email address: \").strip().lower()\n",
+    "\n",
+    "if not email or \"@\" not in email:\n",
+    "    raise ValueError(\"Invalid email address. Please enter a valid email.\")\n",
+    "\n",
+    "# Hash email for privacy and determinism\n",
+    "email_hash = hashlib.md5(email.encode()).hexdigest()[:6]\n",
+    "\n",
+    "# Build identifier: -workshop-YYYYMMDD-<hash>\n",
+    "today = date.today()\n",
+    "date_str = today.strftime('%Y%m%d')\n",
+    "workshop_identifier = f\"-workshop-{date_str}-{email_hash}\"\n",
+    "\n",
+    "# Save to artifacts directory for use in Terraform notebook\n",
+    "identifier_file = Path(bootstrap_info['artifacts_dir']) / \"workshop_identifier.json\"\n",
+    "identifier_data = {\n",
+    "    \"email_hash\": email_hash,\n",
+    "    \"identifier\": workshop_identifier,\n",
+    "    \"date\": date_str,\n",
+    "    \"created_at\": date.today().isoformat()\n",
+    "}\n",
+    "\n",
+    "with open(identifier_file, 'w') as f:\n",
+    "    json.dump(identifier_data, f, indent=2)\n",
+    "\n",
+    "print(f\"\\n✅ Workshop identifier generated:\")\n",
+    "print(f\"   Identifier: {workshop_identifier}\")\n",
+    "print(f\"   Date component: {date_str}\")\n",
+    "print(f\"   Hash (from email): {email_hash}\")\n",
+    "print(f\"\\n💡 This identifier will be used for all Terraform resources\")\n",
+    "print(f\"   Saved to: {identifier_file}\")\n",
+    "print(f\"\\n⚠️  IMPORTANT: Use the same email address if you re-run this notebook\")\n",
+    "print(f\"   to ensure Terraform can manage existing resources.\")\n"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -153,7 +224,6 @@
     "required_vars = [\n",
     "    \"WORKSHOP_NAME\",\n",
     "    \"NAMESPACE\",\n",
-    "    \"CLUSTER_NAME\",\n",
     "    \"TERRAFORM_DIR\",\n",
     "    \"HELM_RELEASE\",\n",
     "    \"HELM_NAMESPACE\",\n",
@@ -222,9 +292,27 @@
     "    get_kubernetes_service_name,\n",
     ")\n",
     "from shared._shell import run\n",
+    "from shared._validation import ok, warn, require_env\n",
+    "from pathlib import Path\n",
+    "import json\n",
+    "\n",
+    "# Load workshop identifier if it exists (from identifier setup cell)\n",
+    "identifier_file = Path(bootstrap_info['artifacts_dir']) / \"workshop_identifier.json\"\n",
+    "if identifier_file.exists():\n",
+    "    with open(identifier_file) as f:\n",
+    "        identifier_data = json.load(f)\n",
+    "    workshop_identifier = identifier_data[\"identifier\"]\n",
+    "    # Compute expected cluster name: langsmith-eks${identifier}\n",
+    "    cluster_name = f\"langsmith-eks{workshop_identifier}\"\n",
+    "    print(f\"💡 Using cluster name from workshop identifier: {cluster_name}\\n\")\n",
+    "else:\n",
+    "    # Fallback to CLUSTER_NAME env var if identifier not set yet\n",
+    "    config = require_env(\"CLUSTER_NAME\")\n",
+    "    cluster_name = config[\"CLUSTER_NAME\"]\n",
+    "    warn(\"Workshop identifier not found - using CLUSTER_NAME from environment\")\n",
+    "    print(\"💡 Run the 'Workshop Identifier Setup' cell above to generate a unique identifier\\n\")\n",
     "\n",
     "provider = get_cloud_provider()\n",
-    "cluster_name = os.environ[\"CLUSTER_NAME\"]\n",
     "region = get_region()\n",
     "k8s_service = get_kubernetes_service_name()\n",
     "\n",

notebooks/module-1/02_terraform_apply.ipynb

@@ -97,6 +97,7 @@
    "source": [
     "import os\n",
     "import re\n",
+    "import json\n",
     "from pathlib import Path\n",
     "from shared._validation import require_env, ok, warn, fail\n",
     "from shared._shell import run\n",
@@ -131,15 +132,41 @@
     "terraform_dir_str = expand_env_vars(config[\"TERRAFORM_DIR\"])\n",
     "terraform_dir = Path(terraform_dir_str).expanduser().resolve()\n",
     "\n",
-    "cluster_name = config[\"CLUSTER_NAME\"]\n",
+    "# Load workshop identifier from preflight notebook\n",
+    "identifier_file = artifacts_dir / \"workshop_identifier.json\"\n",
+    "if not identifier_file.exists():\n",
+    "    fail(f\"Workshop identifier not found: {identifier_file}\")\n",
+    "    print(\"\\n💡 To fix this:\")\n",
+    "    print(\"   1. Run the preflight notebook (01_preflight.ipynb) first\")\n",
+    "    print(\"   2. Complete the 'Workshop Identifier Setup' cell\")\n",
+    "    print(\"   3. Then return to this notebook\")\n",
+    "    raise RuntimeError(f\"Workshop identifier not found. Please run 01_preflight.ipynb first.\")\n",
+    "\n",
+    "with open(identifier_file) as f:\n",
+    "    identifier_data = json.load(f)\n",
+    "\n",
+    "workshop_identifier = identifier_data[\"identifier\"]\n",
+    "print(f\"✅ Loaded workshop identifier: {workshop_identifier}\")\n",
+    "\n",
+    "# Compute expected cluster name for validation/display\n",
+    "# Terraform computes: cluster_name = \"langsmith-eks${local.identifier}\"\n",
+    "cluster_name = f\"langsmith-eks{workshop_identifier}\"\n",
+    "\n",
     "region = config[region_var]\n",
     "workshop_name = config[\"WORKSHOP_NAME\"]\n",
     "\n",
-    "print(\"### Terraform Configuration\")\n",
+    "print(\"\\n### Terraform Configuration\")\n",
     "print(f\"Terraform Directory: {terraform_dir}\")\n",
-    "print(f\"Cluster Name: {cluster_name}\")\n",
+    "print(f\"Workshop Identifier: {workshop_identifier}\")\n",
+    "print(f\"Expected Cluster Name: {cluster_name}\")\n",
     "print(f\"Region: {region}\")\n",
-    "print(f\"Workshop Name: {workshop_name}\\n\")\n",
+    "print(f\"Workshop Name: {workshop_name}\")\n",
+    "print(f\"\\n💡 Terraform will use this identifier for all resource names:\")\n",
+    "print(f\"   Cluster: langsmith-eks{workshop_identifier}\")\n",
+    "print(f\"   Redis: langsmith-redis{workshop_identifier}\")\n",
+    "print(f\"   S3: langsmith-s3{workshop_identifier}\")\n",
+    "print(f\"   Postgres: langsmith-postgres{workshop_identifier}\")\n",
+    "print(f\"   VPC: langsmith-vpc{workshop_identifier}\\n\")\n",
     "\n",
     "if not terraform_dir.exists():\n",
     "    fail(f\"Terraform directory does not exist: {terraform_dir}\")\n",
@@ -371,6 +398,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "import getpass\n",
+    "\n",
     "# Create terraform plan\n",
     "plan_file = artifacts_dir / \"terraform-plan.txt\"\n",
     "\n",
@@ -383,7 +412,22 @@
     "postgres_username = os.environ.get(\"POSTGRES_USERNAME\", \"\").strip()\n",
     "postgres_password = os.environ.get(\"POSTGRES_PASSWORD\", \"\").strip()\n",
     "\n",
+    "if not postgres_username:\n",
+    "    print(\"Please provide a PostgreSQL username: \")\n",
+    "    postgres_username = input().strip()\n",
+    "\n",
+    "if not postgres_password:\n",
+    "    print(\"Please provide a PostgreSQL password: \")\n",
+    "    postgres_password = getpass.getpass().strip()\n",
+    "\n",
     "print(\"### Terraform Variables\\n\")\n",
+    "\n",
+    "# Pass workshop identifier to Terraform\n",
+    "# This is the key variable that controls all resource naming\n",
+    "terraform_vars.extend([\"-var\", f\"identifier={workshop_identifier}\"])\n",
+    "print(f\"✅ IDENTIFIER: {workshop_identifier}\")\n",
+    "print(f\"   This will be used for all resource names (cluster, redis, s3, postgres, vpc)\\n\")\n",
+    "\n",
     "missing_vars = []\n",
     "\n",
     "if postgres_username:\n",

notebooks/shared/_validation.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 import os
+from datetime import date
 
 def ok(msg: str) -> None:
     print(f"✅ {msg}")
@@ -18,6 +19,9 @@ def require_env(*keys: str) -> dict:
         if not v:
             missing.append(k)
         cfg[k] = v
+        if k == 'CLUSTER_NAME':
+            # Add a hardcoded prefix to the cluster name
+            cfg[k] = f"langsmith-workshop-{date.today().strftime('%Y%m%d')}-{v}"
     if missing:
         fail(f"Missing required environment variables: {', '.join(missing)}")
     return cfg