feat: add -T/--timestamps (env LOGPROXY_TIMESTAMPS) option to prepend strftime to each line

src/log_proxy.c

@@ -114,7 +114,7 @@ static void every_second() {
             // another program rotated our log file
             // => let's reinit the output channel
             destroy_output_channel();
-            init_output_channel(log_file, use_locks, TRUE, chmod_str, chown_str, chgrp_str);
+            init_output_channel(log_file, use_locks, TRUE, chmod_str, chown_str, chgrp_str, timestamp_prefix);
             unlock_control_file(fd);
             return;
         }
@@ -141,7 +141,7 @@ static void every_second() {
             }
             if (rotate_res == TRUE) {
                 destroy_output_channel();
-                init_output_channel(log_file, use_locks, TRUE, chmod_str, chown_str, chgrp_str);
+                init_output_channel(log_file, use_locks, TRUE, chmod_str, chown_str, chgrp_str, timestamp_prefix);
             }
         }
         unlock_control_file(fd);
@@ -202,7 +202,7 @@ void init_or_reinit_output_channel(const gchar *lg_file, gboolean us_locks) {
         exit(2);
     }
     destroy_output_channel();
-    init_output_channel(lg_file, us_locks, FALSE, chmod_str, chown_str, chgrp_str);
+    init_output_channel(lg_file, us_locks, FALSE, chmod_str, chown_str, chgrp_str, timestamp_prefix);
     unlock_control_file(lock_fd);
 }
 
@@ -212,7 +212,7 @@ int main(int argc, char *argv[])
     setlocale(LC_ALL, "");
     context = g_option_context_new("LOGFILE  - log proxy");
     g_option_context_add_main_entries(context, entries, NULL);
-    gchar *description = "Optional environment variables to override defaults: \n    LOGPROXY_ROTATION_SIZE\n    LOGPROXY_ROTATION_TIME\n    LOGPROXY_ROTATION_SUFFIX\n    LOGPROXY_LOG_DIRECTORY\n    LOGPROXY_ROTATED_FILES\n\nExample for rotation-size option:\n- If log_proxy is run with the option --rotation-size on the command line, rotation-size will take the provided value\n- If the option --rotation-size is not provided on command line :\n  - If the environment variable LOGPROXY_ROTATION_SIZE is set, rotation-size will take this value\n  - If the environment variable LOGPROXY_ROTATION_SIZE is not set, rotation-size will take the default value 104857600\n";
+    gchar *description = "Optional environment variables to override defaults: \n    LOGPROXY_ROTATION_SIZE\n    LOGPROXY_ROTATION_TIME\n    LOGPROXY_ROTATION_SUFFIX\n    LOGPROXY_LOG_DIRECTORY\n    LOGPROXY_ROTATED_FILES\n    LOGPROXY_TIMESTAMPS\n\nExample for rotation-size option:\n- If log_proxy is run with the option --rotation-size on the command line, rotation-size will take the provided value\n- If the option --rotation-size is not provided on command line :\n  - If the environment variable LOGPROXY_ROTATION_SIZE is set, rotation-size will take this value\n  - If the environment variable LOGPROXY_ROTATION_SIZE is not set, rotation-size will take the default value 104857600\n";
     g_option_context_set_description(context, description);
     if (!g_option_context_parse(context, &argc, &argv, NULL)) {
         g_print("%s", g_option_context_get_help(context, TRUE, NULL));

src/log_proxy_wrapper.c

@@ -64,7 +64,7 @@ void spawn_logproxy_async(const gchar *fifo_path, const gchar *log_path) {
     if (use_locks) {
         use_locks_str = "--use-locks";
     }
-    gchar *cli = g_strdup_printf("log_proxy -s %li -t %li -S \"%s\" -d \"%s\" -n %i %s -r -f \"%s\" \"%s\"", rotation_size, rotation_time, rotation_suffix, log_directory, rotated_files, use_locks_str, fifo_path, log_path);
+    gchar *cli = g_strdup_printf("log_proxy -s %li -t %li -S \"%s\" -d \"%s\" -T \"%s\" -n %i %s -r -f \"%s\" \"%s\"", rotation_size, rotation_time, rotation_suffix, log_directory, timestamp_prefix, rotated_files, use_locks_str, fifo_path, log_path);
     gboolean spawn_res = g_spawn_command_line_async(cli, NULL);
     if (spawn_res == FALSE) {
         g_critical("can't spawn %s => exit", cli);

src/options.h

@@ -10,6 +10,7 @@ static gchar *log_file = NULL;
 static glong rotation_size = -1;
 static glong rotation_time = -1;
 static gchar *rotation_suffix = NULL;
+static gchar *timestamp_prefix = NULL;
 static gchar *log_directory = NULL;
 static gchar *chmod_str = NULL;
 static gchar *chown_str = NULL;
@@ -70,6 +71,16 @@ void set_default_values_from_env()
         }
     }
 
+    if ( timestamp_prefix ==  NULL ) {
+        env_val = g_getenv("LOGPROXY_TIMESTAMPS");
+        if ( env_val != NULL ) {
+            timestamp_prefix = (gchar *)env_val;
+        }
+    }
+    if ( timestamp_prefix !=  NULL && strlen(timestamp_prefix) == 0 ) {
+        timestamp_prefix = NULL;
+    }
+
     if ( log_directory ==  NULL ) {
         env_val = g_getenv("LOGPROXY_LOG_DIRECTORY");
         if ( env_val != NULL ) {
@@ -94,6 +105,7 @@ static GOptionEntry entries[] = {
     { "rotation-suffix", 'S', 0, G_OPTION_ARG_STRING, &rotation_suffix, "strftime based suffix to append to rotated log files (default: content of environment variable LOGPROXY_ROTATION_SUFFIX or .%%Y%%m%%d%%H%%M%%S)", NULL },
     { "log-directory", 'd', 0, G_OPTION_ARG_STRING, &log_directory, "directory to store log files (default: content of environment variable LOGPROXY_LOG_DIRECTORY or current directory), directory is created if missing", NULL },
     { "rotated-files", 'n', 0, G_OPTION_ARG_INT, &rotated_files, "maximum number of rotated files to keep including main one (0 => no cleaning, default: content of environment variable LOGPROXY_ROTATED_FILES or 5)", NULL },
+    { "timestamps", 'T', 0, G_OPTION_ARG_STRING, &timestamp_prefix, "strftime prefix to prepend to every output line (default: content of environment variable LOGPROXY_TIMESTAMPS or none)", NULL },
     { "chmod", 'c', 0, G_OPTION_ARG_STRING, &chmod_str, "if set, chmod the logfile to this value, '0700' for example (default: content of environment variable LOGPROXY_CHMOD or NULL)", NULL },
     { "chown", 'o', 0, G_OPTION_ARG_STRING, &chown_str, "if set, try (if you don't have sufficient privileges, it will fail silently) to change the owner of the logfile to the given user value", NULL },
     { "chgrp", 'g', 0, G_OPTION_ARG_STRING, &chgrp_str, "if set, try (if you don't have sufficient privileges, it will fail silently) to change the group of the logfile to the given group value", NULL },

src/out.c

@@ -14,6 +14,7 @@ static GIOChannel *_out_channel = NULL;
 static gboolean _use_locks = FALSE;
 static gchar *_log_file = NULL;
 static glong _log_file_initial_timestamp = 0;
+static gchar *_timestamp_prefix = NULL;
 
 glong get_output_channel_age() {
     g_assert(_log_file_initial_timestamp > 0);
@@ -29,8 +30,9 @@ void destroy_output_channel() {
     g_free(_log_file);
 }
 
-void init_output_channel(const gchar *log_file, gboolean use_locks, gboolean force_control_file, const gchar *chmod_str, const gchar *chown_str, const gchar *chgrp_str) {
+void init_output_channel(const gchar *log_file, gboolean use_locks, gboolean force_control_file, const gchar *chmod_str, const gchar *chown_str, const gchar *chgrp_str, const gchar *timestamp_prefix) {
     _log_file = g_strdup(log_file);
+    _timestamp_prefix = g_strdup(timestamp_prefix);
     _use_locks = use_locks;
     create_empty(_log_file);
     _log_file_initial_timestamp = -1;
@@ -91,13 +93,27 @@ gboolean write_output_channel(GString *buffer) {
     GIOStatus write_status;
     GError *error = NULL;
     gsize written;
+    gsize written_timestamp = 0;
     while (TRUE) {
         if (_use_locks) {
             int res = flock(g_io_channel_unix_get_fd(_out_channel), LOCK_EX);
             if (res < 0) {
                 continue;
             }
         }
+
+        if ( _timestamp_prefix != NULL && written_timestamp == 0 ) {
+            gchar *timestamp = compute_timestamp_prefix(_timestamp_prefix);
+            if ( timestamp != NULL ) {
+                write_status = g_io_channel_write_chars(_out_channel, timestamp,
+                        strlen(timestamp), &written_timestamp, &error);
+                g_free(timestamp);
+                if (write_status == G_IO_STATUS_AGAIN) {
+                    continue;
+                }
+            }
+        }
+
         write_status = g_io_channel_write_chars(_out_channel, buffer->str,
                 buffer->len, &written, &error);
         if (_use_locks) {

src/out.h

@@ -3,7 +3,7 @@
 
 #include <glib.h>
 
-void init_output_channel(const gchar *log_file, gboolean use_locks, gboolean force_control_file, const gchar *chmod_str, const gchar *chown_str, const gchar *chgrp_str);
+void init_output_channel(const gchar *log_file, gboolean use_locks, gboolean force_control_file, const gchar *chmod_str, const gchar *chown_str, const gchar *chgrp_str, const gchar *timestamp_prefix);
 void destroy_output_channel();
 gboolean write_output_channel(GString *buffer);
 glong get_output_channel_age();

src/util.c

@@ -115,6 +115,26 @@ gchar *compute_strftime_suffix(const gchar *str, const gchar *strftime_suffix) {
     return g_strdup_printf("%s%s", str, outstr);
 }
 
+/**
+ * Format current timestamp prefix to prepend to a log line.
+ *
+ * @param strftime_prefix format with strftime placeholders to expand with current time.
+ * @return newly allocated string (free it with g_free) with the current timestamp prefix.
+ */
+gchar *compute_timestamp_prefix(const gchar *strftime_prefix) {
+    time_t t;
+    struct tm *tmp;
+    t = time(NULL);
+    tmp = localtime(&t);
+    g_assert(tmp != NULL);
+    char outstr[100];
+    if (strftime(outstr, sizeof(outstr), strftime_prefix, tmp) == 0) {
+        g_critical("problem with strftime on %s", strftime_prefix);
+        return NULL;
+    }
+    return g_strdup(outstr);
+}
+
 /**
  * Compute absolute file path from directory path and file name
  *

src/util.h

@@ -7,6 +7,7 @@
 glong get_file_size(const gchar *file_path);
 glong get_current_timestamp();
 gchar *compute_strftime_suffix(const gchar *str, const gchar *strftime_suffix);
+gchar *compute_timestamp_prefix(const gchar *strftime_prefix);
 gchar *get_unique_hexa_identifier();
 glong get_file_inode(const gchar *file_path);
 glong get_fd_inode(int fd);