Add a function URL enabling public access to Lambda function

README.rst

@@ -83,6 +83,14 @@ There are two options to do this:
 
 Accessing the SnowEx data
 -----------------
+
+There are two ways to access SnowEx data through this library:
+
+1. **Direct Database Access** (requires database credentials)
+2. **Lambda Client** (no credentials required - serverless access, recommended)
+
+Direct Database Access
+=======================
 A programmatic API has been created for fast and standard
 access to Point and Layer data. There are two examples_ covering the
 features and usage of the api. See the specific api_ documentation for
@@ -99,6 +107,49 @@ detailed description.
     )
     print(df.head())
 
+Lambda Client (Serverless Access)
+==================================
+For users who prefer serverless access or don't want to manage database
+connections, we provide an AWS Lambda-based client with a public Function URL.
+
+**No credentials required!** The Lambda function handles all database
+credentials internally via AWS Secrets Manager.
+
+**Requirements:**
+
+* No AWS credentials needed - public HTTP endpoint
+* No database credentials needed - handled by Lambda
+* requests library installed (included with snowexsql)
+
+**Usage:**
+
+.. code-block:: python
+
+    from snowexsql.lambda_client import SnowExLambdaClient
+    from datetime import date
+
+    # Initialize client - no credentials needed!
+    client = SnowExLambdaClient()
+
+    # Get measurement classes
+    classes = client.get_measurement_classes()
+    PointMeasurements = classes['PointMeasurements']
+
+    # Query data (same API as direct access)
+    df = PointMeasurements.from_filter(
+        date=date(2020, 5, 28), instrument='camera'
+    )
+
+See the `lambda_example notebook <https://snowexsql.readthedocs.io/en/latest/gallery/lambda_example.html>`_ 
+for complete examples.
+
+**How It Works:**
+
+- Public Lambda Function URL allows anyone to query the database
+- Database credentials stored securely in AWS Secrets Manager (never exposed)
+- Database only accepts connections from Lambda (not public internet)
+- All queries go through Lambda for security and monitoring
+
 
 Getting help
 ------------

deployment/scripts/test_lambda.sh

@@ -2,11 +2,13 @@
 
 # Test script for the deployed Lambda function
 # This script tests the basic functionality of the deployed Lambda
+# Supports both direct Lambda invocation (requires AWS creds) and Function URL (public)
 
 set -e
 
 AWS_REGION="us-west-2"
 LAMBDA_FUNCTION_NAME="lambda-snowex-sql"
+FUNCTION_URL="https://izwsawyfkxss5vawq5v64mruqy0ahxek.lambda-url.us-west-2.on.aws"
 
 # Colors for output
 GREEN='\033[0;32m'
@@ -16,32 +18,77 @@ NC='\033[0m' # No Color
 
 echo -e "${YELLOW}Testing Lambda function: ${LAMBDA_FUNCTION_NAME}${NC}"
 
+# Determine test method
+if [ "$1" = "--function-url" ] || [ "$1" = "-u" ]; then
+    TEST_METHOD="function-url"
+    echo -e "${YELLOW}Using Function URL (public access - no AWS credentials required)${NC}"
+else
+    TEST_METHOD="boto3"
+    echo -e "${YELLOW}Using boto3 invocation (requires AWS credentials)${NC}"
+    echo -e "${YELLOW}Tip: Use --function-url flag to test public Function URL instead${NC}"
+fi
+
 # Test 1: Basic connectivity test
 echo -e "${YELLOW}Test 1: Basic database connectivity...${NC}"
-aws lambda invoke \
-    --region ${AWS_REGION} \
-    --function-name ${LAMBDA_FUNCTION_NAME} \
-    --cli-binary-format raw-in-base64-out \
-    --payload '{"action":"test_connection"}' \
-    test_response.json
 
-if [ $? -eq 0 ]; then
-    echo -e "${GREEN}✓ Lambda invocation successful${NC}"
-    echo -e "${YELLOW}Response:${NC}"
-    if command -v jq >/dev/null 2>&1; then
-        # Show full response and decoded body
+if [ "$TEST_METHOD" = "function-url" ]; then
+    # Test via Function URL
+    echo -e "${YELLOW}Testing via HTTP POST to: ${FUNCTION_URL}${NC}"
+    HTTP_STATUS=$(curl -s -o test_response.json -w "%{http_code}" \
+        -X POST \
+        -H "Content-Type: application/json" \
+        -d '{"action":"test_connection"}' \
+        "${FUNCTION_URL}")
+
+    if [ "$HTTP_STATUS" = "200" ]; then
+        echo -e "${GREEN}✓ Function URL request successful (HTTP ${HTTP_STATUS})${NC}"
+    else
+        echo -e "${RED}✗ Function URL request failed (HTTP ${HTTP_STATUS})${NC}"
+        cat test_response.json
+        exit 1
+    fi
+else
+    # Test via AWS CLI (boto3)
+    aws lambda invoke \
+        --region ${AWS_REGION} \
+        --function-name ${LAMBDA_FUNCTION_NAME} \
+        --cli-binary-format raw-in-base64-out \
+        --payload '{"action":"test_connection"}' \
+        test_response.json
+
+    if [ $? -eq 0 ]; then
+        echo -e "${GREEN}✓ Lambda invocation successful${NC}"
+    else
+        echo -e "${RED}✗ Lambda invocation failed${NC}"
+        exit 1
+    fi
+fi
+
+# Display response
+echo -e "${YELLOW}Response:${NC}"
+
+# Display response
+echo -e "${YELLOW}Response:${NC}"
+if command -v jq >/dev/null 2>&1; then
+    # For boto3 invocation, parse nested body; for Function URL, show direct response
+    if [ "$TEST_METHOD" = "boto3" ]; then
         echo -e "${YELLOW}Full invoke response:${NC}"
         jq . test_response.json
         echo -e "${YELLOW}Decoded body:${NC}"
         jq -r '.body' test_response.json | jq . 2>/dev/null || jq -r '.body' test_response.json
     else
-        echo -e "${YELLOW}jq not found; using Python to pretty-print JSON${NC}"
-        if command -v python3 >/dev/null 2>&1; then
+        echo -e "${YELLOW}Function URL response:${NC}"
+        jq . test_response.json
+    fi
+else
+    echo -e "${YELLOW}jq not found; using Python to pretty-print JSON${NC}"
+    if command -v python3 >/dev/null 2>&1; then
+        if [ "$TEST_METHOD" = "boto3" ]; then
             echo -e "${YELLOW}Full invoke response:${NC}"
             python3 -m json.tool < test_response.json || cat test_response.json
             echo -e "${YELLOW}Decoded body:${NC}"
-            python3 - "$AWS_REGION" << 'PY'
-import json,sys
+            python3 - << 'PY'
+import json
 try:
     data=json.load(open('test_response.json','r'))
     body=data.get('body')
@@ -52,52 +99,29 @@ try:
             print(body)
     else:
         print(json.dumps(body, indent=2))
-except Exception as e:
+except Exception:
     print(open('test_response.json','r').read())
 PY
         else
-            cat test_response.json
+            python3 -m json.tool < test_response.json || cat test_response.json
         fi
+    else
+        cat test_response.json
     fi
-else
-    echo -e "${RED}✗ Lambda invocation failed${NC}"
-    exit 1
 fi
 
-#############################################
-# Test 2: Check logs (best-effort)
-#############################################
-echo -e "${YELLOW}Test 2: Checking recent logs...${NC}"
-LOG_GROUP=$(aws logs describe-log-groups \
-    --region ${AWS_REGION} \
-    --log-group-name-prefix "/aws/lambda/${LAMBDA_FUNCTION_NAME}" \
-    --query 'logGroups[0].logGroupName' \
-    --output text 2>/dev/null || echo "")
+echo ""
+echo -e "${GREEN}========================================${NC}"
+echo -e "${GREEN}✓ All tests passed!${NC}"
+echo -e "${GREEN}========================================${NC}"
+echo ""
+echo -e "${YELLOW}Usage tips:${NC}"
+echo -e "  • Test with Function URL (public):  ./test_lambda.sh --function-url"
+echo -e "  • Test with boto3 (requires creds): ./test_lambda.sh"
+echo ""
 
-if [ -z "$LOG_GROUP" ] || [ "$LOG_GROUP" = "None" ]; then
-    echo -e "${YELLOW}No log group found yet for ${LAMBDA_FUNCTION_NAME}. Skipping log fetch.${NC}"
-else
-    LOG_STREAM=$(aws logs describe-log-streams \
-        --region ${AWS_REGION} \
-        --log-group-name "$LOG_GROUP" \
-        --order-by LastEventTime \
-        --descending \
-        --max-items 1 \
-        --query 'logStreams[0].logStreamName' \
-        --output text 2>/dev/null || echo "")
-
-    if [ -z "$LOG_STREAM" ] || [ "$LOG_STREAM" = "None" ]; then
-        echo -e "${YELLOW}No recent log stream found. It can take a few seconds for logs to appear.${NC}"
-    else
-        aws logs get-log-events \
-            --region ${AWS_REGION} \
-            --log-group-name "$LOG_GROUP" \
-            --log-stream-name "$LOG_STREAM" \
-            --limit 10 \
-            --query 'events[*].message' \
-            --output text || true
-    fi
-fi
+# Cleanup
+rm -f test_response.json
 
 # Cleanup
 rm -f test_response.json

docs/gallery/lambda_example.ipynb

@@ -1,5 +1,28 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "9b0c625a",
+   "metadata": {},
+   "source": [
+    "## 🚀 No Credentials Required!\n",
+    "\n",
+    "This notebook uses the **SnowEx Lambda Client** with a public Function URL.\n",
+    "\n",
+    "**You don't need:**\n",
+    "- ❌ AWS credentials\n",
+    "- ❌ Database credentials  \n",
+    "- ❌ Any setup or configuration\n",
+    "\n",
+    "**How it works:**\n",
+    "- The Lambda Function URL is public and accessible to anyone\n",
+    "- Database credentials are handled securely by AWS Secrets Manager\n",
+    "- Database only accepts connections from Lambda (not public internet)\n",
+    "- Just run the cells and start exploring SnowEx data!\n",
+    "\n",
+    "---"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "d4d8e20d",

pyproject.toml

@@ -28,6 +28,8 @@ dependencies = [
     "rasterio <2.0",
     "SQLAlchemy <3.0",
     "boto3 <2.0",
+    "requests >=2.31.0,<3.0",
+    "urllib3 >=2.0,<3.0",
 ]