From 24e6ae9ade081e0c1a3f7527b891202d5d40d366 Mon Sep 17 00:00:00 2001
From: Jules Villard <jul@fb.com>
Date: Wed, 28 Dec 2016 02:49:15 -0800
Subject: [PATCH] [log] re-use log file names

Summary:
Instead of opening new log files each time with non-deterministic names, keep
appending to the same log files. This only removes the randomized part of the
names in the files. In particular, it keeps the name prefixes for, eg, clang
source files.

Also changed most "<executable>/<executable>-out.log" to simply "<executable>/out.log".

Reviewed By: jberdine

Differential Revision: D4365983

fbshipit-source-id: 46792dc
---
 infer/src/backend/infer.ml |  2 +-
 infer/src/base/Logging.ml  | 28 +++++++++++++++-------------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/infer/src/backend/infer.ml b/infer/src/backend/infer.ml
index 1079dfe68..5ef1b8763 100644
--- a/infer/src/backend/infer.ml
+++ b/infer/src/backend/infer.ml
@@ -302,7 +302,7 @@ let () =
     remove_results_dir () ;
   create_results_dir () ;
   (* re-set log files, as default files were in results_dir removed above *)
-  L.set_log_file_identifier Config.current_exe (Some (CLOpt.exe_name Config.current_exe)) ;
+  L.set_log_file_identifier Config.current_exe None ;
   if Config.print_builtins then Builtin.print_and_exit () ;
   if Config.is_originator then L.do_out "%s@\n" Config.version_string ;
   (* infer might be called from a Makefile and itself uses `make` to run the analysis in parallel,
diff --git a/infer/src/base/Logging.ml b/infer/src/base/Logging.ml
index 29c3fb852..ece42a1b9 100644
--- a/infer/src/base/Logging.ml
+++ b/infer/src/base/Logging.ml
@@ -44,27 +44,29 @@ let set_log_file_identifier (current_exe : CLOpt.exe) string_opt =
   if should_setup_log_files then (
     let name_prefix =
       (match string_opt with
-       | Some name -> name ^ "_"
+       | Some name -> name ^ "-"
        | None -> ""
-      ) ^ Pid.to_string (Unix.getpid ()) ^ "_" in
+      ) in
     let exe_log_dir =
-      let log_dir = Config.results_dir ^/ Config.log_dir_name in
-      log_dir ^/ (log_dir_of_current_exe current_exe) in
+      Config.results_dir ^/ Config.log_dir_name ^/ log_dir_of_current_exe current_exe in
     let fmt_chan_file name suffix = lazy (
+      let file =
+        (* the command-line option takes precedence if specified *)
+        if name <> "" then name
+        else exe_log_dir ^/ name_prefix^suffix in
       try
         Unix.mkdir_p exe_log_dir ;
-        let file =
-          (* the command-line option takes precedence if specified *)
-          if name <> "" then name
-          else Filename.temp_file ~in_dir:exe_log_dir name_prefix suffix in
-        let chan = Pervasives.open_out file in
+        let chan = Pervasives.open_out_gen [Open_append; Open_creat] 0o666 file in
         let fmt = F.formatter_of_out_channel chan in
+        Format.fprintf fmt
+          "---- start logging from %d -------------------------------------------@\n"
+          (Pid.to_int (Unix.getpid ()));
         (fmt, chan, file)
       with Sys_error _ ->
-        failwithf "ERROR: cannot open log file %s@\n" name
+        failwithf "ERROR: cannot open log file \"%s\"" file
     ) in
-    let out_fmt_chan_file = fmt_chan_file Config.out_file_cmdline "-out.log" in
-    let err_fmt_chan_file = fmt_chan_file Config.err_file_cmdline "-err.log" in
+    let out_fmt_chan_file = fmt_chan_file Config.out_file_cmdline "out.log" in
+    let err_fmt_chan_file = fmt_chan_file Config.err_file_cmdline "err.log" in
     Pervasives.at_exit (fun () ->
         let close fmt_chan_file =
           if Lazy.is_val fmt_chan_file then (
@@ -84,7 +86,7 @@ let set_log_file_identifier (current_exe : CLOpt.exe) string_opt =
   )
 
 (* set up log files on startup if needed *)
-let () = set_log_file_identifier Config.current_exe (Some (CLOpt.exe_name Config.current_exe))
+let () = set_log_file_identifier Config.current_exe None
 
 let log_file_names () = (Lazy.force !out_file, Lazy.force !err_file)