Merge pull request #562 from p12tic/journald-labels

logging: Add container labels to log entries on journald

Author: rhatdan

docs/conmon.8.md

@@ -69,6 +69,10 @@ Maximum size of the log file (in bytes).
 **--log-tag**
 Additional tag to use for logging.
 
+**--log-label**
+Additional label to use for logging.  The accepted format is LABEL=VALUE.  Can be specified multiple times.
+Note that LABEL must contain only uppercase letters, numbers and underscore character.
+
 **-n**, **--name**
 Container name.
 

src/cli.c

@@ -49,6 +49,7 @@ int opt_exit_delay = 0;
 gboolean opt_replace_listen_pid = FALSE;
 char *opt_log_level = NULL;
 char *opt_log_tag = NULL;
+gchar **opt_log_labels = NULL;
 gboolean opt_sync = FALSE;
 gboolean opt_no_sync_log = FALSE;
 char *opt_sdnotify_socket = NULL;
@@ -78,6 +79,8 @@ GOptionEntry opt_entries[] = {
 	{"log-size-max", 0, 0, G_OPTION_ARG_INT64, &opt_log_size_max, "Maximum size of log file", NULL},
 	{"log-global-size-max", 0, 0, G_OPTION_ARG_INT64, &opt_log_global_size_max, "Maximum size of all log files", NULL},
 	{"log-tag", 0, 0, G_OPTION_ARG_STRING, &opt_log_tag, "Additional tag to use for logging", NULL},
+	{"log-label", 0, 0, G_OPTION_ARG_STRING_ARRAY, &opt_log_labels,
+	 "Additional label to include in logs. Can be specified multiple times", NULL},
 	{"name", 'n', 0, G_OPTION_ARG_STRING, &opt_name, "Container name", NULL},
 	{"no-new-keyring", 0, 0, G_OPTION_ARG_NONE, &opt_no_new_keyring, "Do not create a new session keyring for the container", NULL},
 	{"no-pivot", 0, 0, G_OPTION_ARG_NONE, &opt_no_pivot, "Do not use pivot_root", NULL},
@@ -194,5 +197,5 @@ void process_cli()
 	if (opt_container_pid_file == NULL)
 		opt_container_pid_file = g_strdup_printf("%s/pidfile-%s", cwd, opt_cid);
 
-	configure_log_drivers(opt_log_path, opt_log_size_max, opt_log_global_size_max, opt_cid, opt_name, opt_log_tag);
+	configure_log_drivers(opt_log_path, opt_log_size_max, opt_log_global_size_max, opt_cid, opt_name, opt_log_tag, opt_log_labels);
 }

src/ctr_logging.c

@@ -2,6 +2,7 @@
 #include "ctr_logging.h"
 #include "cli.h"
 #include "config.h"
+#include <ctype.h>
 #include <string.h>
 #include <sys/stat.h>
 
@@ -70,6 +71,7 @@ static char *container_id_full = NULL;
 static char *container_id = NULL;
 static char *container_name = NULL;
 static char *container_tag = NULL;
+static gchar **container_labels = NULL;
 static size_t container_tag_len;
 static char *syslog_identifier = NULL;
 static size_t syslog_identifier_len;
@@ -96,13 +98,43 @@ gboolean logging_is_passthrough(void)
 	return use_logging_passthrough;
 }
 
+static int count_chars_in_string(const char *str, char ch)
+{
+	int count = 0;
+
+	while (str) {
+		str = strchr(str, ch);
+		if (str == NULL)
+			break;
+		count++;
+		str++;
+	}
+
+	return count;
+}
+
+static int is_valid_label_name(const char *str)
+{
+	while (*str) {
+		if (*str == '=') {
+			return 1;
+		}
+		if (!isupper(*str) && !isdigit(*str) && *str != '_') {
+			return 0;
+		}
+		str++;
+	}
+	return 1;
+}
+
 /*
  * configures container log specific information, such as the drivers the user
  * called with and the max log size for log file types. For the log file types
  * (currently just k8s log file), it will also open the log_fd for that specific
  * log file.
  */
-void configure_log_drivers(gchar **log_drivers, int64_t log_size_max_, int64_t log_global_size_max_, char *cuuid_, char *name_, char *tag)
+void configure_log_drivers(gchar **log_drivers, int64_t log_size_max_, int64_t log_global_size_max_, char *cuuid_, char *name_, char *tag,
+			   gchar **log_labels)
 {
 	log_size_max = log_size_max_;
 	log_global_size_max = log_global_size_max_;
@@ -126,8 +158,14 @@ void configure_log_drivers(gchar **log_drivers, int64_t log_size_max_, int64_t l
 		}
 		k8s_total_bytes_written = k8s_bytes_written;
 
-		if (!use_journald_logging && tag)
-			nexit("k8s-file doesn't support --log-tag");
+		if (!use_journald_logging) {
+			if (!tag) {
+				nexit("k8s-file doesn't support --log-tag");
+			}
+			if (!log_labels) {
+				nexit("k8s-file doesn't support --log-label");
+			}
+		}
 	}
 
 	if (use_journald_logging) {
@@ -169,6 +207,24 @@ void configure_log_drivers(gchar **log_drivers, int64_t log_size_max_, int64_t l
 			syslog_identifier = g_strdup_printf("SYSLOG_IDENTIFIER=%s", tag);
 			syslog_identifier_len = strlen(syslog_identifier);
 		}
+		if (log_labels) {
+			container_labels = log_labels;
+
+			/* Ensure that valid LABEL=VALUE pairs have been passed */
+			for (char **ptr = log_labels; *ptr; ptr++) {
+				if (**ptr == '=') {
+					nexitf("Container labels must be in format LABEL=VALUE (no LABEL present in '%s')", *ptr);
+				}
+				if (count_chars_in_string(*ptr, '=') != 1) {
+					nexitf("Container labels must be in format LABEL=VALUE (none or more than one '=' present in '%s')",
+					       *ptr);
+				}
+				if (!is_valid_label_name(*ptr)) {
+					nexitf("Container label names must contain only uppercase letters, numbers and underscore (in '%s')",
+					       *ptr);
+				}
+			}
+		}
 	}
 }
 
@@ -325,6 +381,12 @@ static int write_journald(int pipe, char *buf, ssize_t buflen)
 		/* per docker journald logging format, CONTAINER_PARTIAL_MESSAGE is set to true if it's partial, but otherwise not set. */
 		if (partial && writev_buffer_append_segment_no_flush(&bufv, "CONTAINER_PARTIAL_MESSAGE=true", PARTIAL_MESSAGE_EQ_LEN) < 0)
 			return -1;
+		if (container_labels) {
+			for (gchar **label = container_labels; *label; ++label) {
+				if (writev_buffer_append_segment_no_flush(&bufv, *label, strlen(*label)) < 0)
+					return -1;
+			}
+		}
 
 		int err = sd_journal_sendv(bufv.iov, bufv.iovcnt);
 		if (err < 0) {

src/ctr_logging.h

@@ -7,7 +7,8 @@
 
 void reopen_log_files(void);
 bool write_to_logs(stdpipe_t pipe, char *buf, ssize_t num_read);
-void configure_log_drivers(gchar **log_drivers, int64_t log_size_max_, int64_t log_global_size_max_, char *cuuid_, char *name_, char *tag);
+void configure_log_drivers(gchar **log_drivers, int64_t log_size_max_, int64_t log_global_size_max_, char *cuuid_, char *name_, char *tag,
+			   gchar **labels);
 void sync_logs(void);
 gboolean logging_is_passthrough(void);
 void close_logging_fds(void);