logging: Support isym_path

Support instance symlinks, which are activated when we are using
g_conf.log_per_instance.

Signed-off-by: Colin McCabe <colinm@hq.newdream.net>

diff --git a/src/common/DoutStreambuf.cc b/src/common/DoutStreambuf.cc
index fe4365d898dd84156957126d8cd2afce15239f51..3715528ee52e99de1247f18c48b5d38bc406a877 100644 (file)
--- a/src/common/DoutStreambuf.cc
+++ b/src/common/DoutStreambuf.cc
@@ -327,6 +327,28 @@ int DoutStreambuf<charT, traits>::handle_pid_change()
   if (opath == new_opath)
     return 0;
 
+  if (!isym_path.empty()) {
+    // Re-create the instance symlink
+    int ret = create_symlink(new_opath, isym_path);
+    if (ret) {
+      ostringstream oss;
+      oss << __func__ << ": failed to (re)create instance symlink";
+      primitive_log(oss.str());
+      return ret;
+    }
+  }
+
+  if (!rsym_path.empty()) {
+    // Re-create the rank symlink
+    int ret = create_symlink(new_opath, rsym_path);
+    if (ret) {
+      ostringstream oss;
+      oss << __func__ << ": failed to (re)create rank symlink";
+      primitive_log(oss.str());
+      return ret;
+    }
+  }
+
   int ret = ::rename(opath.c_str(), new_opath.c_str());
   if (ret) {
     int err = errno;
@@ -339,12 +361,6 @@ int DoutStreambuf<charT, traits>::handle_pid_change()
 
   opath = new_opath;
 
-//  // $type.$id symlink
-//  if (g_conf.log_per_instance && _dout_name_symlink_path[0])
-//    create_symlink(_dout_name_symlink_path);
-//  if (_dout_rank_symlink_path[0])
-//    create_symlink(_dout_rank_symlink_path);
-
   return 0;
 }
 
@@ -364,6 +380,8 @@ std::string DoutStreambuf<charT, traits>::config_to_str() const
   oss << "flags = 0x" << std::hex << flags << std::dec << "\n";
   oss << "ofd = " << ofd << "\n";
   oss << "opath = '" << opath << "'\n";
+  oss << "isym_path = '" << isym_path << "'\n";
+  oss << "rsym_path = '" << rsym_path << "'\n";
   oss << "log_sym_history = " << g_conf.log_sym_history  << "\n";
   return oss.str();
 }
@@ -441,6 +459,10 @@ std::string DoutStreambuf<charT, traits>::_calculate_opath() const
 template <typename charT, typename traits>
 bool DoutStreambuf<charT, traits>::_read_ofile_config()
 {
+  int ret;
+
+  isym_path = "";
+  rsym_path = "";
   opath = _calculate_opath();
   if (opath.empty()) {
     ostringstream oss;
@@ -449,6 +471,36 @@ bool DoutStreambuf<charT, traits>::_read_ofile_config()
     return false;
   }
 
+  if (empty(g_conf.log_file) && g_conf.log_per_instance) {
+    // Calculate instance symlink path (isym_path)
+    std::string symlink_dir;
+    if (empty(g_conf.log_sym_dir))
+      symlink_dir = get_dirname(opath);
+    else
+      symlink_dir = g_conf.log_sym_dir;
+    ostringstream iss;
+    iss << symlink_dir << "/" << g_conf.type << "." << g_conf.id;
+    isym_path = iss.str();
+
+    // Rotate isym_path
+    ret = _rotate_files(isym_path);
+    if (ret) {
+      ostringstream oss;
+      oss << __func__ << ": failed to rotate instance symlinks";
+      primitive_log(oss.str());
+      return ret;
+    }
+
+    // Create isym_path
+    ret = create_symlink(opath, isym_path);
+    if (ret) {
+      ostringstream oss;
+      oss << __func__ << ": failed to create instance symlink";
+      primitive_log(oss.str());
+      return ret;
+    }
+  }
+
   assert(ofd == -1);
   ofd = open(opath.c_str(),
            O_CREAT | O_WRONLY | O_CLOEXEC | O_APPEND, S_IWUSR | S_IRUSR);
@@ -464,5 +516,78 @@ bool DoutStreambuf<charT, traits>::_read_ofile_config()
   return true;
 }
 
+template <typename charT, typename traits>
+int DoutStreambuf<charT, traits>::_rotate_files(const std::string &base)
+{
+  // Given a file name base, and a directory like this:
+  // base
+  // base.1
+  // base.2
+  // base.3
+  // base.4
+  // unrelated_blah
+  // unrelated_blah.1
+  //
+  // We'll take the following actions:
+  // base                rename to base.1
+  // base.1              rename to base.2
+  // base.2              rename to base.3
+  // base.3              (unlink)
+  // base.4              (unlink)
+  // unrelated_blah      (do nothing)
+  // unrelated_blah.1    (do nothing)
+
+  signed int i;
+  for (i = -1; i < INT_MAX; ++i) {
+    ostringstream oss;
+    oss << base;
+    if (i != -1)
+      oss << "." << i;
+    string path(oss.str());
+
+    if (::access(path.c_str(), R_OK | W_OK))
+      break;
+  }
+  signed int max_symlink = i - 1;
+
+  for (signed int j = max_symlink; j >= -1; --j) {
+    ostringstream oss;
+    oss << base;
+    if (j != -1)
+      oss << "." << j;
+    string path(oss.str());
+
+    signed int k = j + 1;
+    if (k >= g_conf.log_sym_history) {
+      if (::unlink(path.c_str())) {
+       int err = errno;
+       ostringstream ess;
+       ess << __func__ << ": failed to unlink '" << path << "': "
+           << cpp_strerror(err) << "\n";
+       primitive_log(ess.str());
+       return err;
+      }
+      //*_dout << "---- " << getpid() << " removed " << path << " ----"
+      //       << std::endl;
+    }
+    else {
+      ostringstream pss;
+      pss << base << "." << k;
+      string new_path(pss.str());
+      if (::rename(path.c_str(), new_path.c_str())) {
+       int err = errno;
+       ostringstream ess;
+       ess << __func__ << ": failed to rename '" << path << "' to "
+           << "'" << new_path << "': " << cpp_strerror(err) << "\n";
+       primitive_log(ess.str());
+       return err;
+      }
+//      *_dout << "---- " << getpid() << " renamed " << path << " -> "
+//      << newpath << " ----" << std::endl;
+    }
+  }
+  return 0;
+}
+
 // Explicit template instantiation
 template class DoutStreambuf <char>;

diff --git a/src/common/DoutStreambuf.h b/src/common/DoutStreambuf.h
index f1aab1bfc7da458a7baa4059c5c2b45e0b4b6d31..30e35cfa9a92ce06e2fb38484f1c65eb9a80fb98 100644 (file)
--- a/src/common/DoutStreambuf.h
+++ b/src/common/DoutStreambuf.h
@@ -87,6 +87,10 @@ private:
   // ofile stuff
   int ofd;
   std::string opath;
+
+  // symlinks
+  std::string isym_path;
+  std::string rsym_path;
 };
 
 #endif