From 4fa1b3faf4485f0b0723aedea1568f9ae4e9a59e Mon Sep 17 00:00:00 2001
From: Eric House <xwords@eehouse.org>
Date: Fri, 10 Jan 2020 16:43:48 -0800
Subject: [PATCH] Don't join a game that's been idle for more than two weeks

The two weeks is configurable. But the idea is somebody creates a game
with a random name but it's never joined. Eventually the name is used
again and the first to connect joins the existing game that will never
progress. I could just prune from the DB, but this is less work ongoing.
---
 xwords4/relay/crefmgr.cpp          |  6 +++---
 xwords4/relay/dbmgr.cpp            | 17 ++++++++++++-----
 xwords4/relay/dbmgr.h              |  8 +++++---
 xwords4/relay/xwrelay.conf_tmplate |  8 ++++++++
 4 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/xwords4/relay/crefmgr.cpp b/xwords4/relay/crefmgr.cpp
index c3d76202e..12fbbfd0b 100644
--- a/xwords4/relay/crefmgr.cpp
+++ b/xwords4/relay/crefmgr.cpp
@@ -254,9 +254,9 @@ CRefMgr::getMakeCookieRef( const char* cookie, int nPlayersH, int nPlayersT,
                                     wantsPublic, connNameBuf, 
                                     sizeof(connNameBuf), &alreadyHere, &cid );
         if ( !*seenSeed ) {
-            cid = m_db->FindOpen( cookie, langCode, nPlayersT, nPlayersH, 
-                                  wantsPublic, connNameBuf, sizeof(connNameBuf), 
-                                  &alreadyHere );
+            cid = m_db->FindRecentOpen( cookie, langCode, nPlayersT, nPlayersH,
+                                        wantsPublic, connNameBuf, sizeof(connNameBuf),
+                                        &alreadyHere );
         }
 
         if ( cid > 0 ) {
diff --git a/xwords4/relay/dbmgr.cpp b/xwords4/relay/dbmgr.cpp
index 4c7252202..936a932ea 100644
--- a/xwords4/relay/dbmgr.cpp
+++ b/xwords4/relay/dbmgr.cpp
@@ -66,6 +66,12 @@ DBMgr::DBMgr()
     m_useB64 = tmp != 0;
     logf( XW_LOGINFO, "%s: m_useB64=%d", __func__, m_useB64 );
 
+    if ( !RelayConfigs::GetConfigs()->GetValueFor( "NEWGAME_INTERVAL",
+                                                   m_interval,
+                                                   sizeof(m_interval) ) ) {
+        assert(0);
+    }
+
     pthread_key_create( &m_conn_key, destr_function );
 
     pthread_mutex_init( &m_haveNoMessagesMutex, NULL );
@@ -330,20 +336,21 @@ DBMgr::SeenSeed( const char* cookie, unsigned short seed,
 }
 
 CookieID
-DBMgr::FindOpen( const char* cookie, int lang, int nPlayersT, int nPlayersH,
-                 bool wantsPublic, char* connNameBuf, int bufLen,
-                 int* nPlayersHP )
+DBMgr::FindRecentOpen( const char* cookie, int lang, int nPlayersT, int nPlayersH,
+                       bool wantsPublic, char* connNameBuf, int bufLen,
+                       int* nPlayersHP )
 {
     QueryBuilder qb;
     qb.appendQueryf("SELECT cid, connName, sum_array(nPerDevice) FROM "
                     GAMES_TABLE
                     " WHERE NOT dead"
+                    " AND now() - interval '%s' < ANY(mtimes) "
                     " AND room ILIKE $$"
                     " AND lang = $$"
                     " AND nTotal = $$"
                     " AND $$ <= nTotal-sum_array(nPerDevice)"
                     " AND $$ = pub"
-                    " LIMIT 1")
+                    " LIMIT 1", m_interval )
         .appendParam(cookie)
         .appendParam(lang)
         .appendParam(nPlayersT)
@@ -366,7 +373,7 @@ DBMgr::FindOpen( const char* cookie, int lang, int nPlayersT, int nPlayersH,
     PQclear( result );
     logf( XW_LOGINFO, "%s=>%d", __func__, cid );
     return cid;
-} /* FindOpen */
+} /* FindRecentOpen */
 
 bool
 DBMgr::AllDevsAckd( const char* const connName )
diff --git a/xwords4/relay/dbmgr.h b/xwords4/relay/dbmgr.h
index 0d1a40e50..42471b5ff 100644
--- a/xwords4/relay/dbmgr.h
+++ b/xwords4/relay/dbmgr.h
@@ -93,9 +93,9 @@ class DBMgr {
                    char* connNameBuf, int bufLen, int* nPlayersHP,
                    CookieID* cid );
 
-    CookieID FindOpen( const char* cookie, int lang, int nPlayersT, 
-                       int nPlayersH, bool wantsPublic, 
-                       char* connNameBuf, int bufLen, int* nPlayersHP );
+    CookieID FindRecentOpen( const char* cookie, int lang, int nPlayersT,
+                             int nPlayersH, bool wantsPublic,
+                             char* connNameBuf, int bufLen, int* nPlayersHP );
     bool AllDevsAckd( const char* const connName );
 
     DevIDRelay RegisterDevice( const DevID* host );
@@ -196,6 +196,8 @@ class DBMgr {
     pthread_key_t m_conn_key;
     bool m_useB64;
 
+    char m_interval[64];
+
     pthread_mutex_t m_haveNoMessagesMutex;
     set<DevIDRelay> m_haveNoMessagesDevID;
     set<StrWPF> m_haveNoMessagesConnname;
diff --git a/xwords4/relay/xwrelay.conf_tmplate b/xwords4/relay/xwrelay.conf_tmplate
index fce4469fd..0074575ba 100644
--- a/xwords4/relay/xwrelay.conf_tmplate
+++ b/xwords4/relay/xwrelay.conf_tmplate
@@ -76,6 +76,14 @@ DB_PORT=5432
 LOGLEVEL=0
 LOGFILE_PATH=./xwrelay.log
 
+# How long after an unjoined game has last been heard from will we
+# refuse to add another device to it? The problem I'm addressing is
+# that with 16-bit ints being used as room names on Android sometimes
+# a new game si generated with the same room as a game whose creating
+# device has been in a landfill for years. Passed into a sql interval
+# statement, e.g.  WHERE ctime >= now() - interval '2 weeks'
+NEWGAME_INTERVAL=14 days
+
 # Delay sending packets so devices/emulators on the same machine as
 # relay have a bit more natural experience
 # SEND_DELAY_MILLIS=500