Add sqlite-vec static extension for vector search in ProxySQL

This commit integrates sqlite-vec (https://github.com/asg017/sqlite-vec)
as a statically linked extension, enabling vector search capabilities
in all ProxySQL SQLite databases (admin, stats, config, monitor).

Changes:
1. Added sqlite-vec source files to deps/sqlite3/sqlite-vec-source/
   - sqlite-vec.c: main extension source
   - sqlite-vec.h: header for static linking
   - sqlite-vec.h.tmpl: template header

2. Modified deps/Makefile:
   - Added target sqlite3/sqlite3/vec.o that copies sources and compiles
     with flags -DSQLITE_CORE -DSQLITE_VEC_STATIC
   - Made sqlite3 target depend on vec.o

3. Modified lib/Makefile:
   - Added $(SQLITE3_LDIR)/vec.o to libproxysql.a prerequisites
   - Included vec.o in the static library archive

4. Modified lib/Admin_Bootstrap.cpp:
   - Added extern "C" declaration for sqlite3_vec_init
   - Enabled load extension support for all databases:
     - admindb, statsdb, configdb, monitordb, statsdb_disk
   - Registered sqlite3_vec_init as auto-extension at database open
     (replacing commented sqlite3_json_init)

5. Updated top-level Makefile:
   - Made GIT_VERSION fallback to git describe --always when tags missing

Result:
- Vector search functions (vec0 virtual tables, vector operations) are
  available in all ProxySQL SQLite databases without runtime dependencies
- No separate shared library required; fully embedded in proxysql binary
- Extension automatically loaded at database initialization

Makefile

@@ -9,7 +9,7 @@
 ### export GIT_VERSION=3.x.y-dev
 ### ```
 
-GIT_VERSION ?= $(shell git describe --long --abbrev=7)
+GIT_VERSION ?= $(shell git describe --long --abbrev=7 2>/dev/null || git describe --long --abbrev=7 --always)
 ifndef GIT_VERSION
     $(error GIT_VERSION is not set)
 endif

deps/Makefile

@@ -246,7 +246,11 @@ sqlite3/sqlite3/sqlite3.o:
 	cd sqlite3/sqlite3 && ${CC} ${MYCFLAGS} -fPIC -c -o sqlite3.o sqlite3.c -DSQLITE_ENABLE_MEMORY_MANAGEMENT -DSQLITE_ENABLE_JSON1 -DSQLITE_DLL=1
 	cd sqlite3/sqlite3 && ${CC} -shared -o libsqlite3.so sqlite3.o
 
-sqlite3: sqlite3/sqlite3/sqlite3.o
+sqlite3/sqlite3/vec.o: sqlite3/sqlite3/sqlite3.o
+	cd sqlite3/sqlite3 && cp ../sqlite-vec-source/sqlite-vec.c . && cp ../sqlite-vec-source/sqlite-vec.h .
+	cd sqlite3/sqlite3 && ${CC} ${MYCFLAGS} -fPIC -c -o vec.o sqlite-vec.c -DSQLITE_CORE -DSQLITE_VEC_STATIC -DSQLITE_ENABLE_MEMORY_MANAGEMENT -DSQLITE_ENABLE_JSON1 -DSQLITE_DLL=1
+
+sqlite3: sqlite3/sqlite3/sqlite3.o sqlite3/sqlite3/vec.o
 
 
 libconfig/libconfig/out/libconfig++.a:

deps/sqlite3/sqlite-vec-source/sqlite-vec.h

@@ -0,0 +1,39 @@
+#ifndef SQLITE_VEC_H
+#define SQLITE_VEC_H
+
+#ifndef SQLITE_CORE
+#include "sqlite3ext.h"
+#else
+#include "sqlite3.h"
+#endif
+
+#ifdef SQLITE_VEC_STATIC
+  #define SQLITE_VEC_API
+#else
+  #ifdef _WIN32
+    #define SQLITE_VEC_API __declspec(dllexport)
+  #else
+    #define SQLITE_VEC_API
+  #endif
+#endif
+
+#define SQLITE_VEC_VERSION "v0.1.0"
+#define SQLITE_VEC_DATE "2025-12-22"
+#define SQLITE_VEC_SOURCE "sqlite-vec.c"
+
+#define SQLITE_VEC_VERSION_MAJOR 0
+#define SQLITE_VEC_VERSION_MINOR 1
+#define SQLITE_VEC_VERSION_PATCH 0
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+SQLITE_VEC_API int sqlite3_vec_init(sqlite3 *db, char **pzErrMsg,
+                  const sqlite3_api_routines *pApi);
+
+#ifdef __cplusplus
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* ifndef SQLITE_VEC_H */

deps/sqlite3/sqlite-vec-source/sqlite-vec.h.tmpl

@@ -0,0 +1,41 @@
+#ifndef SQLITE_VEC_H
+#define SQLITE_VEC_H
+
+#ifndef SQLITE_CORE
+#include "sqlite3ext.h"
+#else
+#include "sqlite3.h"
+#endif
+
+#ifdef SQLITE_VEC_STATIC
+  #define SQLITE_VEC_API
+#else
+  #ifdef _WIN32
+    #define SQLITE_VEC_API __declspec(dllexport)
+  #else
+    #define SQLITE_VEC_API
+  #endif
+#endif
+
+#define SQLITE_VEC_VERSION "v${VERSION}"
+// TODO rm
+#define SQLITE_VEC_DATE "${DATE}"
+#define SQLITE_VEC_SOURCE "${SOURCE}"
+
+
+#define SQLITE_VEC_VERSION_MAJOR ${VERSION_MAJOR}
+#define SQLITE_VEC_VERSION_MINOR ${VERSION_MINOR}
+#define SQLITE_VEC_VERSION_PATCH ${VERSION_PATCH}
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+SQLITE_VEC_API int sqlite3_vec_init(sqlite3 *db, char **pzErrMsg,
+                  const sqlite3_api_routines *pApi);
+
+#ifdef __cplusplus
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* ifndef SQLITE_VEC_H */

lib/Admin_Bootstrap.cpp

@@ -67,6 +67,7 @@ using json = nlohmann::json;
 #include <sys/utsname.h>
 
 #include "platform.h"
+extern "C" int sqlite3_vec_init(sqlite3 *db, char **pzErrMsg, const sqlite3_api_routines *pApi);
 #include "microhttpd.h"
 
 #if (defined(__i386__) || defined(__x86_64__) || defined(__ARM_ARCH_3__) || defined(__mips__)) && defined(__linux)
@@ -511,10 +512,11 @@ bool ProxySQL_Admin::init(const bootstrap_info_t& bootstrap_info) {
 	admindb=new SQLite3DB();
 	admindb->open((char *)"file:mem_admindb?mode=memory&cache=shared", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FULLMUTEX);
 	admindb->execute("PRAGMA cache_size = -50000");
-	//sqlite3_enable_load_extension(admindb->get_db(),1);
-	//sqlite3_auto_extension( (void(*)(void))sqlite3_json_init);
+	sqlite3_enable_load_extension(admindb->get_db(),1);
+	sqlite3_auto_extension( (void(*)(void))sqlite3_vec_init);
 	statsdb=new SQLite3DB();
 	statsdb->open((char *)"file:mem_statsdb?mode=memory&cache=shared", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FULLMUTEX);
+	sqlite3_enable_load_extension(statsdb->get_db(),1);
 
 	// check if file exists , see #617
 	bool admindb_file_exists=Proxy_file_exists(GloVars.admindb);
@@ -527,15 +529,18 @@ bool ProxySQL_Admin::init(const bootstrap_info_t& bootstrap_info) {
 		}
 	}
 	configdb->open((char *)GloVars.admindb, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FULLMUTEX);
+	sqlite3_enable_load_extension(configdb->get_db(),1);
 	// Fully synchronous is not required. See to #1055
 	// https://sqlite.org/pragma.html#pragma_synchronous
 	configdb->execute("PRAGMA synchronous=0");
 
 	monitordb = new SQLite3DB();
 	monitordb->open((char *)"file:mem_monitordb?mode=memory&cache=shared", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FULLMUTEX);
+	sqlite3_enable_load_extension(monitordb->get_db(),1);
 
 	statsdb_disk = new SQLite3DB();
 	statsdb_disk->open((char *)GloVars.statsdb_disk, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FULLMUTEX);
+	sqlite3_enable_load_extension(statsdb_disk->get_db(),1);
 //	char *dbname = (char *)malloc(strlen(GloVars.statsdb_disk)+50);
 //	sprintf(dbname,"%s?mode=memory&cache=shared",GloVars.statsdb_disk);
 //	statsdb_disk->open(dbname, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_NOMUTEX | SQLITE_OPEN_FULLMUTEX);

lib/Makefile

@@ -89,8 +89,8 @@ HEADERS := ../include/*.h ../include/*.hpp
 $(ODIR)/%.oo: %.cpp $(HEADERS)
 	$(CXX) -fPIC -c -o $@ $< $(MYCXXFLAGS) $(CXXFLAGS)
 
-libproxysql.a: $(ODIR) $(OBJ) $(OBJ_CXX) $(SQLITE3_LDIR)/sqlite3.o
-	ar rcs $@ $(OBJ) $(OBJ_CXX) $(SQLITE3_LDIR)/sqlite3.o
+libproxysql.a: $(ODIR) $(OBJ) $(OBJ_CXX) $(SQLITE3_LDIR)/sqlite3.o $(SQLITE3_LDIR)/vec.o
+	ar rcs $@ $(OBJ) $(OBJ_CXX) $(SQLITE3_LDIR)/sqlite3.o $(SQLITE3_LDIR)/vec.o
 
 $(ODIR):
 	mkdir $(ODIR)