Initial commit

skills/databases/references/mongodb-atlas.md

@@ -0,0 +1,465 @@
+# MongoDB Atlas Cloud Platform
+
+MongoDB Atlas is fully-managed cloud database service with automated backups, monitoring, and scaling.
+
+## Quick Start
+
+### Create Free Cluster
+1. Sign up at mongodb.com/atlas
+2. Create organization and project
+3. Build cluster (M0 Free Tier)
+   - Cloud provider: AWS/GCP/Azure
+   - Region: closest to users
+   - Cluster name
+4. Create database user (username/password)
+5. Whitelist IP address (or 0.0.0.0/0 for development)
+6. Get connection string
+
+### Connection String Format
+```
+mongodb+srv://username:password@cluster.mongodb.net/database?retryWrites=true&w=majority
+```
+
+### Connect
+```javascript
+// Node.js
+const { MongoClient } = require("mongodb");
+const uri = "mongodb+srv://...";
+const client = new MongoClient(uri);
+
+await client.connect();
+const db = client.db("myDatabase");
+```
+
+```python
+# Python
+from pymongo import MongoClient
+uri = "mongodb+srv://..."
+client = MongoClient(uri)
+db = client.myDatabase
+```
+
+## Cluster Tiers
+
+### M0 (Free Tier)
+- 512 MB storage
+- Shared CPU/RAM
+- Perfect for development/learning
+- Limited to 100 connections
+- No backups
+
+### M10+ (Dedicated Clusters)
+- Dedicated resources
+- 2GB - 4TB+ storage
+- Automated backups
+- Advanced monitoring
+- Performance Advisor
+- Multi-region support
+- VPC peering
+
+### Serverless
+- Pay per operation
+- Auto-scales to zero
+- Good for sporadic workloads
+- 1GB+ storage
+- Limited features (no full-text search)
+
+## Database Configuration
+
+### Create Database
+```javascript
+// Via Atlas UI: Database → Add Database
+// Via shell
+use myNewDatabase
+db.createCollection("myCollection")
+
+// Via driver
+const db = client.db("myNewDatabase");
+await db.createCollection("myCollection");
+```
+
+### Schema Validation
+```javascript
+// Set validation rules in Atlas UI or via shell
+db.createCollection("users", {
+  validator: {
+    $jsonSchema: {
+      bsonType: "object",
+      required: ["email", "name"],
+      properties: {
+        email: { bsonType: "string", pattern: "^.+@.+$" },
+        age: { bsonType: "int", minimum: 0 }
+      }
+    }
+  }
+})
+```
+
+## Security
+
+### Network Access
+```javascript
+// IP Whitelist (Atlas UI → Network Access)
+// - Add IP Address: specific IPs
+// - 0.0.0.0/0: allow from anywhere (dev only)
+// - VPC Peering: private connection
+
+// Connection string includes options
+mongodb+srv://cluster.mongodb.net/?retryWrites=true&w=majority&ssl=true
+```
+
+### Database Users
+```javascript
+// Create via Atlas UI → Database Access
+// - Username/password authentication
+// - AWS IAM authentication
+// - X.509 certificates
+
+// Roles:
+// - atlasAdmin: full access
+// - readWriteAnyDatabase: read/write all databases
+// - readAnyDatabase: read-only all databases
+// - read/readWrite: database-specific
+```
+
+### Encryption
+```javascript
+// Encryption at rest (automatic on M10+)
+// Encryption in transit (TLS/SSL, always enabled)
+
+// Client-Side Field Level Encryption (CSFLE)
+const autoEncryptionOpts = {
+  keyVaultNamespace: "encryption.__keyVault",
+  kmsProviders: {
+    aws: {
+      accessKeyId: process.env.AWS_ACCESS_KEY_ID,
+      secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY
+    }
+  }
+};
+
+const client = new MongoClient(uri, { autoEncryption: autoEncryptionOpts });
+```
+
+## Backups and Snapshots
+
+### Cloud Backups (M10+)
+```javascript
+// Automatic continuous backups
+// - Snapshots every 6-24 hours
+// - Oplog for point-in-time recovery
+// - Retention: 2+ days configurable
+
+// Restore via Atlas UI:
+// 1. Clusters → cluster name → Backup tab
+// 2. Select snapshot or point in time
+// 3. Download or restore to cluster
+```
+
+### Manual Backups
+```bash
+# Export using mongodump
+mongodump --uri="mongodb+srv://user:pass@cluster.mongodb.net/mydb" --out=/backup
+
+# Restore using mongorestore
+mongorestore --uri="mongodb+srv://..." /backup/mydb
+```
+
+## Monitoring and Alerts
+
+### Metrics Dashboard
+```javascript
+// Atlas UI → Metrics
+// Key metrics:
+// - Operations per second
+// - Query execution times
+// - Connections
+// - Network I/O
+// - Disk usage
+// - CPU utilization
+
+// Real-time Performance panel
+// - Current operations
+// - Slow queries
+// - Index suggestions
+```
+
+### Alerts
+```javascript
+// Configure via Atlas UI → Alerts
+// Alert types:
+// - High connections (> threshold)
+// - High CPU usage (> 80%)
+// - Disk usage (> 90%)
+// - Replication lag
+// - Backup failures
+
+// Notification channels:
+// - Email
+// - SMS
+// - Slack
+// - PagerDuty
+// - Webhook
+```
+
+### Performance Advisor
+```javascript
+// Automatic index recommendations
+// Atlas UI → Performance Advisor
+
+// Analyzes:
+// - Slow queries
+// - Missing indexes
+// - Redundant indexes
+// - Index usage statistics
+
+// Provides:
+// - Index creation commands
+// - Expected performance improvement
+// - Schema design suggestions
+```
+
+## Atlas Search (Full-Text Search)
+
+### Create Search Index
+```javascript
+// Atlas UI → Search → Create Index
+
+// JSON definition
+{
+  "mappings": {
+    "dynamic": false,
+    "fields": {
+      "title": {
+        "type": "string",
+        "analyzer": "lucene.standard"
+      },
+      "description": {
+        "type": "string",
+        "analyzer": "lucene.english"
+      },
+      "tags": {
+        "type": "string"
+      }
+    }
+  }
+}
+```
+
+### Search Queries
+```javascript
+// Aggregation pipeline with $search
+db.articles.aggregate([
+  {
+    $search: {
+      text: {
+        query: "mongodb database tutorial",
+        path: ["title", "description"],
+        fuzzy: { maxEdits: 1 }
+      }
+    }
+  },
+  { $limit: 10 },
+  {
+    $project: {
+      title: 1,
+      description: 1,
+      score: { $meta: "searchScore" }
+    }
+  }
+])
+
+// Autocomplete
+db.articles.aggregate([
+  {
+    $search: {
+      autocomplete: {
+        query: "mong",
+        path: "title",
+        tokenOrder: "sequential"
+      }
+    }
+  }
+])
+```
+
+## Atlas Vector Search (AI/ML)
+
+### Create Vector Search Index
+```javascript
+// For AI similarity search (embeddings)
+{
+  "fields": [
+    {
+      "type": "vector",
+      "path": "embedding",
+      "numDimensions": 1536,  // OpenAI embeddings
+      "similarity": "cosine"
+    }
+  ]
+}
+```
+
+### Vector Search Query
+```javascript
+// Search by similarity
+db.products.aggregate([
+  {
+    $vectorSearch: {
+      index: "vector_index",
+      path: "embedding",
+      queryVector: [0.123, 0.456, ...],  // 1536 dimensions
+      numCandidates: 100,
+      limit: 10
+    }
+  },
+  {
+    $project: {
+      name: 1,
+      description: 1,
+      score: { $meta: "vectorSearchScore" }
+    }
+  }
+])
+```
+
+## Data Federation
+
+### Query Across Sources
+```javascript
+// Federated database instance
+// Query data from:
+// - Atlas clusters
+// - AWS S3
+// - HTTP endpoints
+
+// Create virtual collection
+{
+  "databases": [{
+    "name": "federated",
+    "collections": [{
+      "name": "sales",
+      "dataSources": [{
+        "storeName": "s3Store",
+        "path": "/sales/*.json"
+      }]
+    }]
+  }]
+}
+
+// Query like normal collection
+use federated
+db.sales.find({ region: "US" })
+```
+
+## Atlas Charts (Embedded Analytics)
+
+### Create Dashboard
+```javascript
+// Atlas UI → Charts → New Dashboard
+// Data source: Atlas cluster
+// Chart types: bar, line, pie, scatter, etc.
+
+// Embed in application
+<iframe
+  src="https://charts.mongodb.com/charts-project/embed/charts?id=..."
+  width="800"
+  height="600"
+/>
+```
+
+## Atlas CLI
+
+```bash
+# Install
+npm install -g mongodb-atlas-cli
+
+# Login
+atlas auth login
+
+# List clusters
+atlas clusters list
+
+# Create cluster
+atlas clusters create myCluster --provider AWS --region US_EAST_1 --tier M10
+
+# Manage users
+atlas dbusers create --username myuser --password mypass
+
+# Backups
+atlas backups snapshots list --clusterName myCluster
+```
+
+## Best Practices
+
+1. **Use connection pooling** - Reuse connections
+```javascript
+const client = new MongoClient(uri, {
+  maxPoolSize: 50,
+  minPoolSize: 10
+});
+```
+
+2. **Enable authentication** - Always use database users, not Atlas users
+
+3. **Restrict network access** - IP whitelist or VPC peering
+
+4. **Monitor regularly** - Set up alerts for key metrics
+
+5. **Index optimization** - Use Performance Advisor recommendations
+
+6. **Backup verification** - Regularly test restores
+
+7. **Right-size clusters** - Start small, scale as needed
+
+8. **Multi-region** - For global applications (M10+)
+
+9. **Read preferences** - Use secondaries for read-heavy workloads
+```javascript
+const client = new MongoClient(uri, {
+  readPreference: "secondaryPreferred"
+});
+```
+
+10. **Connection string security** - Use environment variables
+```javascript
+const uri = process.env.MONGODB_URI;
+```
+
+## Troubleshooting
+
+### Connection Issues
+```javascript
+// Check IP whitelist
+// Verify credentials
+// Test connection string
+
+// Verbose logging
+const client = new MongoClient(uri, {
+  serverSelectionTimeoutMS: 5000,
+  loggerLevel: "debug"
+});
+```
+
+### Performance Issues
+```javascript
+// Check Performance Advisor
+// Review slow query logs
+// Analyze index usage
+db.collection.aggregate([{ $indexStats: {} }])
+
+// Check connection count
+db.serverStatus().connections
+```
+
+### Common Errors
+```javascript
+// MongoNetworkError: IP not whitelisted
+// → Add IP to Network Access
+
+// Authentication failed: wrong credentials
+// → Verify username/password in Database Access
+
+// Timeout: connection string or network issue
+// → Check connection string format, DNS resolution
+```