Re: [tarantool-patches] [PATCH v4 1/4] Configurable syslog destination

[Vladimir Davydov <vdavydov.dev@gmail.com>]

On Tue, Jul 31, 2018 at 01:18:30PM +0300, Olga Arkhangelskaia wrote:
> Added server option to syslog configuration.
> Server option is responsible for log destination. At the momemt
> there is two ways of usage:server=unix:/path/to/socket or
> server=ipv4:port. If port is not set default udp port 514 is used.
> If logging to syslog is set, however there is no sever options -
> default location is used: Linux /dev/log and Mac /var/run/syslog.
> 
> Closes #3487
> ---
>  src/say.c | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
>  src/say.h |  13 +++++++-
>  2 files changed, 110 insertions(+), 6 deletions(-)
> 
> diff --git a/src/say.c b/src/say.c
> index ac221dd19..526b8862f 100644
> --- a/src/say.c
> +++ b/src/say.c
> @@ -45,6 +46,7 @@
>  #include <arpa/inet.h>
>  #include <coio_task.h>
>  
> +#define DEFAULT_PORT 514

We don't use macros when we can define a constant in a enum, e.g.

	enum { DEFAULT_PORT = 512 };

Also, DEFAULT_PORT is a too generic name. I think you should prefix it
with SAY_SYSLOG_.

>  pid_t log_pid = 0;
>  int log_level = S_INFO;
>  enum say_format log_format = SF_PLAIN;
> @@ -473,16 +475,85 @@ syslog_connect_unix(const char *path)
>  	return fd;
>  }
>  
> +/**
> + * Connect to remote syslogd using server:port.
> + * @param server address string of remote host.

_ is missing between 'server' and 'address'.

> + * @retval not 0 Socket descriptor.
> + * @retval    -1 Socket error.
> + */
> +static int
> +syslog_connect_remote(const char *server_address)
> +{
> +	struct addrinfo *inf, hints, *ptr;
> +	const char *remote;
> +	char buf[10];
> +	char *portnum, *copy;
> +	int fd = -1;
> +
> +	copy = strdup(server_address);
> +	if (copy == NULL) {
> +		diag_set(OutOfMemory, strlen(server_address), "malloc",
> +			 "stslog server address");
> +		return fd;
> +	}
> +	portnum = copy;
> +	remote = strsep(&portnum, ":");
> +	if (portnum == NULL) {
> +		snprintf(buf, sizeof(buf), "%d", DEFAULT_PORT);
> +		portnum = buf;
> +	}
> +	memset(&hints, 0, sizeof(hints));
> +	hints.ai_family = AF_INET;
> +	hints.ai_socktype = SOCK_DGRAM;
> +	hints.ai_protocol = IPPROTO_UDP;
> +
> +	if (getaddrinfo(remote, (const char*)portnum, NULL, &inf) < 0) {
> +		diag_set(SystemError, "syslog: getaddrinfo failed %s",
> +			 gai_strerror(errno));

First, getaddrinfo() doesn't set errno. You are supposed to call
gai_strerror() on the code it returned.

Second, SystemError always appends strerror(errno) to the error message.
Since getaddrinfo() doesn't do that, you should set errno manually. EIO
seems to be a good choice. Take a look at coio_getaddrinfo() for an
example.

Third, there's no point to prepend the error message with "syslog:".
diag_set() includes file name and string to the error message so finding
a culprit shouldn't be a problem.

> +		goto out;
> +	}
> +	for (ptr = inf; ptr; ptr = ptr->ai_next) {
> +		fd = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
> +		if (fd < 0) {
> +			diag_set(SystemError, "syslog: socket failed %s",
> +				 strerror(errno));

Again. No point to prepend "syslog:" and append strerror(errno).

> +			continue;
> +		}
> +		if (connect(fd, inf->ai_addr, inf->ai_addrlen) != 0) {
> +			close(fd);
> +			fd = -1;
> +			diag_set(SystemError, "syslog:connect failed %s",
> +				 strerror(errno));

Ditto.

> +			continue;
> +		}
> +		break;
> +	}
> +	freeaddrinfo(inf);
> +out:
> +	free(copy);
> +	return fd;
> +}

> diff --git a/src/say.h b/src/say.h
> index 2c2395fe0..73697b1b7 100644
> --- a/src/say.h
> +++ b/src/say.h
> @@ -79,6 +79,12 @@ say_log_level_is_enabled(int level)
>  
>  extern enum say_format log_format;
>  
> +enum say_logger_syslog_server {

Let's rename this to say_syslog_server_type?

> +	SAY_SYSLOG_DEFAULT,
> +	SAY_SYSLOG_UNIX,
> +	SAY_SYSLOG_REMOTE
> +};
> +
>  enum say_logger_type {
>  	/**
>  	 * Before the app server core is initialized, we do not
> @@ -141,7 +147,10 @@ struct log {
>  	/** The current log level. */
>  	int level;
>  	enum say_logger_type type;
> -	/** path to file if logging to file. */
> +	enum say_logger_syslog_server server_type;

Missing comment to 'server_type'. Also, let's prefix it with 'syslog_',
like other syslog-related options (syslog_identity, syslog_facility).

> +	/** Path to file if logging to file, socket
> +	 *  or server address in case of syslog.
> +	 */

/**
 * Malformed comment format.
 * Multi-line comments should look like this.
 */