```rust
1: //! Distributed session management using Redis
2: //!
3: //! This module provides session storage that works across multiple proxy nodes.
4: //! Sessions are stored in Redis and can be accessed by any proxy instance.
5: 
6: use common::{CacheLayer, CacheError, CacheResult, SessionData};
7: use uuid::Uuid;
8: use chrono::{DateTime, Utc, Duration};
9: 
10: /// Session manager for distributed auth sessions
11: #[derive(Clone)]
12: pub struct SessionManager {
13:     cache: CacheLayer,
14:     session_ttl: u64, // Session TTL in seconds
15: }
16: 
17: impl SessionManager {
18:     /// Create a new session manager
19:     pub fn new(cache: CacheLayer, session_ttl: u64) -> Self {
20:         Self { cache, session_ttl }
21:     }
22: 
23:     /// Create a new session for a user
24:     pub async fn create_session(
25:         &self,
26:         user_id: Uuid,
27:         email: String,
28:         role: String,
29:     ) -> CacheResult<String> {
30:         let session_token = Uuid::new_v4().to_string();
31:         let now = Utc::now();
32:         let expires_at = now + Duration::seconds(self.session_ttl as i64);
33: 
34:         let session = SessionData {
35:             user_id,
36:             email,
37:             role,
38:             created_at: now,
39:             expires_at,
40:         };
41: 
42:         // Store session in Redis
43:         let key = format!("session:{}", session_token);
44:         self.cache.set(&key, &session).await?;
45: 
46:         // Also add to user's active sessions set (for multi-device logout)
47:         let user_sessions_key = format!("user:{}:sessions", user_id);
48:         if let Some(redis) = &self.cache.redis {
49:             let mut conn = redis.get_async_connection().await?;
50:             redis::cmd("SADD")
51:                 .arg(&user_sessions_key)
52:                 .arg(&session_token)
53:                 .query_async(&mut conn)
54:                 .await?;
55: 
56:             // Set expiration on the set
57:             redis::cmd("EXPIRE")
58:                 .arg(&user_sessions_key)
59:                 .arg(self.session_ttl * 2)
60:                 .query_async(&mut conn)
61:                 .await?;
62:         }
63: 
64:         Ok(session_token)
65:     }
66: 
67:     /// Get a session by token
68:     pub async fn get_session(&self, session_token: &str) -> CacheResult<Option<SessionData>> {
69:         self.cache.get_session(session_token.to_string()).await
70:     }
71: 
72:     /// Validate a session (check if it exists and is not expired)
73:     pub async fn validate_session(&self, session_token: &str) -> CacheResult<Option<SessionData>> {
74:         let session = self.get_session(session_token).await?;
75:         
76:         if let Some(session) = session {
77:             let now = Utc::now();
78:             if now < session.expires_at {
79:                 return Ok(Some(session));
80:             }
81:         }
82: 
83:         Ok(None)
84:     }
85: 
86:     /// Refresh a session (extend expiration)
87:     pub async fn refresh_session(&self, session_token: &str) -> CacheResult<bool> {
88:         if let Some(mut session) = self.get_session(session_token).await? {
89:             let now = Utc::now();
90:             session.expires_at = now + Duration::seconds(self.session_ttl as i64);
91:             
92:             let key = format!("session:{}", session_token);
93:             self.cache.set(&key, &session).await?;
94:             return Ok(true);
95:         }
96: 
97:         Ok(false)
98:     }
99: 
100:     /// Delete a session (logout)
101:     pub async fn delete_session(&self, session_token: &str) -> CacheResult<()> {
102:         // Get the session first to remove from user's session set
103:         if let Some(session) = self.get_session(session_token).await? {
104:             let user_sessions_key = format!("user:{}:sessions", session.user_id);
105:             
106:             if let Some(redis) = &self.cache.redis {
107:                 let mut conn = redis.get_async_connection().await?;
108:                 redis::cmd("SREM")
109:                     .arg(&user_sessions_key)
110:                     .arg(session_token)
111:                     .query_async(&mut conn)
112:                     .await?;
113:             }
114:         }
115: 
116:         self.cache.delete_session(session_token.to_string()).await
117:     }
118: 
119:     /// Delete all sessions for a user (logout from all devices)
120:     pub async fn delete_all_user_sessions(&self, user_id: Uuid) -> CacheResult<usize> {
121:         let user_sessions_key = format!("user:{}:sessions", user_id);
122:         
123:         if let Some(redis) = &self.cache.redis {
124:             let mut conn = redis.get_async_connection().await?;
125:             
126:             // Get all session tokens for this user
127:             let session_tokens: Vec<String> = redis::cmd("SMEMBERS")
128:                 .arg(&user_sessions_key)
129:                 .query_async(&mut conn)
130:                 .await?;
131: 
132:             let count = session_tokens.len();
133: 
134:             // Delete each session
135:             for token in &session_tokens {
136:                 let session_key = format!("session:{}", token);
137:                 redis::cmd("DEL")
138:                     .arg(&session_key)
139:                     .query_async(&mut conn)
140:                     .await?;
141:             }
142: 
143:             // Delete the user's session set
144:             redis::cmd("DEL")
145:                 .arg(&user_sessions_key)
146:                 .query_async(&mut conn)
147:                 .await?;
148: 
149:             Ok(count)
150:         } else {
151:             Ok(0)
152:         }
153:     }
154: 
155:     /// Get all active sessions for a user
156:     pub async fn get_user_sessions(&self, user_id: Uuid) -> CacheResult<Vec<SessionData>> {
157:         let user_sessions_key = format!("user:{}:sessions", user_id);
158:         
159:         if let Some(redis) = &self.cache.redis {
160:             let mut conn = redis.get_async_connection().await?;
161:             
162:             let session_tokens: Vec<String> = redis::cmd("SMEMBERS")
163:                 .arg(&user_sessions_key)
164:                 .query_async(&mut conn)
165:                 .await?;
166: 
167:             let mut sessions = Vec::new();
168:             for token in session_tokens {
169:                 if let Some(session) = self.get_session(&token).await? {
170:                     sessions.push(session);
171:                 }
172:             }
173: 
174:             Ok(sessions)
175:         } else {
176:             Ok(vec![])
177:         }
178:     }
179: 
180:     /// Count active sessions for a user
181:     pub async fn get_user_session_count(&self, user_id: Uuid) -> CacheResult<usize> {
182:         let sessions = self.get_user_sessions(user_id).await?;
183:         Ok(sessions.len())
184:     }
185: }
186: 
187: #[cfg(test)]
188: mod tests {
189:     use super::*;
190: 
191:     #[tokio::test]
192:     async fn test_session_manager_creation() {
193:         let cache = CacheLayer::new(None, 3600);
194:         let manager = SessionManager::new(cache, 3600);
195:         assert_eq!(manager.session_ttl, 3600);
196:     }
197: }
```