Bypass errors in logging for non-msft-prod environments (#392)

* Removed the logger and verified that the logging capability is the root cause of our consistent segfault errors in python.  Perhaps it also will fix any issues in our label test too?  I'd like to push it to GH and see.

* Formatting fixes

* Revert "Formatting fixes"

This reverts commit 9042595.

* Revert "Removed the logger and verified that the logging capability is the root cause of our consistent segfault errors in python.  Perhaps it also will fix any issues in our label test too?  I'd like to push it to GH and see."

This reverts commit 7561009.

* The custom logging implementation is causing segfaults in python. We're not sure exactly where, but this is the easiest and quickest way to getting a working python release.

* All the integration tests are failing, and there's a chance the virtual dtor on AbstractDataStore might be the culprit, though I am not sure why.  I'm hoping it is so it won't fall on the logging changes.

* Formatting. Again.

include/abstract_data_store.h

@@ -18,6 +18,8 @@ template <typename data_t> class AbstractDataStore
   public:
     AbstractDataStore(const location_t capacity, const size_t dim);
 
+    // virtual ~AbstractDataStore() = default;
+
     // Return number of points returned
     virtual location_t load(const std::string &filename) = 0;
 

include/logger.h

@@ -14,8 +14,13 @@
 
 namespace diskann
 {
+#ifdef ENABLE_CUSTOM_LOGGER
 DISKANN_DLLEXPORT extern std::basic_ostream<char> cout;
 DISKANN_DLLEXPORT extern std::basic_ostream<char> cerr;
+#else
+using std::cerr;
+using std::cout;
+#endif
 
 enum class DISKANN_DLLEXPORT LogLevel
 {

include/logger_impl.h

@@ -11,6 +11,7 @@
 
 namespace diskann
 {
+#ifdef ENABLE_CUSTOM_LOGGER
 class ANNStreamBuf : public std::basic_streambuf<char>
 {
   public:
@@ -36,30 +37,25 @@ class ANNStreamBuf : public std::basic_streambuf<char>
     int flush();
     void logImpl(char *str, int numchars);
 
-// Why the two buffer-sizes? If we are running normally, we are basically
-// interacting with a character output system, so we short-circuit the
-// output process by keeping an empty buffer and writing each character
-// to stdout/stderr. But if we are running in OLS, we have to take all
-// the text that is written to diskann::cout/diskann:cerr, consolidate it
-// and push it out in one-shot, because the OLS infra does not give us
-// character based output. Therefore, we use a larger buffer that is large
-// enough to store the longest message, and continuously add characters
-// to it. When the calling code outputs a std::endl or std::flush, sync()
-// will be called and will output a log level, component name, and the text
-// that has been collected. (sync() is also called if the buffer is full, so
-// overflows/missing text are not a concern).
-// This implies calling code _must_ either print std::endl or std::flush
-// to ensure that the message is written immediately.
-#ifdef ENABLE_CUSTOM_LOGGER
+    // Why the two buffer-sizes? If we are running normally, we are basically
+    // interacting with a character output system, so we short-circuit the
+    // output process by keeping an empty buffer and writing each character
+    // to stdout/stderr. But if we are running in OLS, we have to take all
+    // the text that is written to diskann::cout/diskann:cerr, consolidate it
+    // and push it out in one-shot, because the OLS infra does not give us
+    // character based output. Therefore, we use a larger buffer that is large
+    // enough to store the longest message, and continuously add characters
+    // to it. When the calling code outputs a std::endl or std::flush, sync()
+    // will be called and will output a log level, component name, and the text
+    // that has been collected. (sync() is also called if the buffer is full, so
+    // overflows/missing text are not a concern).
+    // This implies calling code _must_ either print std::endl or std::flush
+    // to ensure that the message is written immediately.
+
     static const int BUFFER_SIZE = 1024;
-#else
-    // Allocating an arbitrarily small buffer here because the overflow() and
-    // other function implementations push the BUFFER_SIZE chars into the
-    // buffer before flushing to fwrite.
-    static const int BUFFER_SIZE = 4;
-#endif
 
     ANNStreamBuf(const ANNStreamBuf &);
     ANNStreamBuf &operator=(const ANNStreamBuf &);
 };
+#endif
 } // namespace diskann

src/logger.cpp

@@ -10,21 +10,19 @@
 namespace diskann
 {
 
+#ifdef ENABLE_CUSTOM_LOGGER
 DISKANN_DLLEXPORT ANNStreamBuf coutBuff(stdout);
 DISKANN_DLLEXPORT ANNStreamBuf cerrBuff(stderr);
 
 DISKANN_DLLEXPORT std::basic_ostream<char> cout(&coutBuff);
 DISKANN_DLLEXPORT std::basic_ostream<char> cerr(&cerrBuff);
-
-#ifdef ENABLE_CUSTOM_LOGGER
 std::function<void(LogLevel, const char *)> g_logger;
 
 void SetCustomLogger(std::function<void(LogLevel, const char *)> logger)
 {
     g_logger = logger;
     diskann::cout << "Set Custom Logger" << std::endl;
 }
-#endif
 
 ANNStreamBuf::ANNStreamBuf(FILE *fp)
 {
@@ -38,11 +36,7 @@ ANNStreamBuf::ANNStreamBuf(FILE *fp)
     }
     _fp = fp;
     _logLevel = (_fp == stdout) ? LogLevel::LL_Info : LogLevel::LL_Error;
-#ifdef ENABLE_CUSTOM_LOGGER
     _buf = new char[BUFFER_SIZE + 1]; // See comment in the header
-#else
-    _buf = new char[BUFFER_SIZE]; // See comment in the header
-#endif
 
     std::memset(_buf, 0, (BUFFER_SIZE) * sizeof(char));
     setp(_buf, _buf + BUFFER_SIZE - 1);
@@ -88,17 +82,16 @@ int ANNStreamBuf::flush()
 }
 void ANNStreamBuf::logImpl(char *str, int num)
 {
-#ifdef ENABLE_CUSTOM_LOGGER
     str[num] = '\0'; // Safe. See the c'tor.
     // Invoke the OLS custom logging function.
     if (g_logger)
     {
         g_logger(_logLevel, str);
     }
+}
 #else
-    fwrite(str, sizeof(char), num, _fp);
-    fflush(_fp);
+using std::cerr;
+using std::cout;
 #endif
-}
 
 } // namespace diskann