From 90287c6d240a168fca8d01f8330e2e2263e1f0a4 Mon Sep 17 00:00:00 2001 From: Sebastian Harl Date: Wed, 26 Mar 2008 09:28:40 +0100 Subject: [PATCH] Disambiguated the protocol used by the unixsock (and other) plugins. As discussed with Florian on IRC, the interpretation of the status line returned by the unixsock plugin (et.al.) is now strictly specified. A status greater than or equal to zero indicates success and the number of subsequent lines of output. A negative status still indicates failure. This way, frontends can manage the output without having to know any command-specific interpretation rules. The GETVAL command has been updated to implement this specification. It now returns each value on a separate line. collectd-unixsock(5) has been updated to reflect the changes. Signed-off-by: Sebastian Harl Signed-off-by: Florian Forster --- src/collectd-unixsock.pod | 54 ++++++++++++++++++++--------------------------- src/utils_cmd_getval.c | 11 +++++----- src/utils_cmd_listval.c | 2 +- 3 files changed, 29 insertions(+), 38 deletions(-) diff --git a/src/collectd-unixsock.pod b/src/collectd-unixsock.pod index b7c9878b..7aa7ac7c 100644 --- a/src/collectd-unixsock.pod +++ b/src/collectd-unixsock.pod @@ -29,6 +29,18 @@ Upon start the C opens a UNIX-socket and waits for connections. Once a connection is established the client can send commands to the daemon which it will answer, if it understand them. +In general the plugin answers with a status line of the following form: + +I I + +If I is greater than or equal to zero the message indicates success, +if I is less than zero the message indicates failure. I is a +human-readable string that further describes the return value. + +On success, I furthermore indicates the number of subsequent lines of +output (not including the status line). Each such lines usually contains a +single return value. See the description of each command for details. + The following commands are implemented: =over 4 @@ -36,40 +48,34 @@ The following commands are implemented: =item B I If the value identified by I (see below) is found the complete -value-list is returned. The response is a space separated list of -name-value-pairs: - -I IB<=>I[ IB<=>I[ ...]] - -If I is less then zero, an error occurred. Otherwise it contains the -number of values that follow. Each value is of the form IB<=>I. +value-list is returned. The response is a list of name-value-pairs, each pair +on its own line (the number of lines is indicated by the status line - see +above). Each name-value-pair is of the form IB<=>I. Counter-values are converted to a rate, e.Eg. bytes per second. Undefined values are returned as B. Example: -> | GETVAL myhost/cpu-0/cpu-user - <- | 1 value=1.260000e+00 + <- | 1 Value found + <- | value=1.260000e+00 =item B Returns a list of the values available in the value cache together with the time of the last update, so that querying applications can issue a B -command for the values that have changed. - -The first line's status number is the number of identifiers returned or less -than zero if an error occurred. Each of the following lines contains the +command for the values that have changed. Each return value consists of the update time as an epoch value and the identifier, separated by a space. The update time is the time of the last value, as provided by the collecting -instance and may be very different from the time the server consideres to be +instance and may be very different from the time the server considers to be "now". Example: -> | LISTVAL <- | 69 Values found - <- | 1182204284 leeloo/cpu-0/cpu-idle - <- | 1182204284 leeloo/cpu-0/cpu-nice - <- | 1182204284 leeloo/cpu-0/cpu-system - <- | 1182204284 leeloo/cpu-0/cpu-user + <- | 1182204284 myhost/cpu-0/cpu-idle + <- | 1182204284 myhost/cpu-0/cpu-nice + <- | 1182204284 myhost/cpu-0/cpu-system + <- | 1182204284 myhost/cpu-0/cpu-user ... =item B I [I] I @@ -208,20 +214,6 @@ some examples: myhost/memory/memory-used myhost/disk-sda/disk_octets -=head2 Return values - -Unless otherwise noted the plugin answers with a line of the following form: - -I I - -If I is zero the message indicates success, if I is non-zero the -message indicates failure. I is a human-readable string that describes -the return value further. - -Commands that return values may use I to return the number of values that -follow, such as the B command. These commands usually return a negative -value on failure and never return zero. - =head1 ABSTRACTION LAYER Shipped with the sourcecode comes the Perl-Module L which diff --git a/src/utils_cmd_getval.c b/src/utils_cmd_getval.c index a4edf4f9..fa5cdf2c 100644 --- a/src/utils_cmd_getval.c +++ b/src/utils_cmd_getval.c @@ -98,17 +98,16 @@ int handle_getval (FILE *fh, char **fields, int fields_num) return (-1); } - fprintf (fh, "%u", (unsigned int) values_num); + fprintf (fh, "%u Value%s found\n", (unsigned int) values_num, + (values_num == 1) ? "" : "s"); for (i = 0; i < values_num; i++) { - fprintf (fh, " %s=", ds->ds[i].name); + fprintf (fh, "%s=", ds->ds[i].name); if (isnan (values[i])) - fprintf (fh, "NaN"); + fprintf (fh, "NaN\n"); else - fprintf (fh, "%12e", values[i]); + fprintf (fh, "%12e\n", values[i]); } - - fprintf (fh, "\n"); fflush (fh); sfree (values); diff --git a/src/utils_cmd_listval.c b/src/utils_cmd_listval.c index 644a67cc..8d6c7836 100644 --- a/src/utils_cmd_listval.c +++ b/src/utils_cmd_listval.c @@ -53,7 +53,7 @@ int handle_listval (FILE *fh, char **fields, int fields_num) return (-1); } - fprintf (fh, "%i Values found\n", (int) number); + fprintf (fh, "%i Value%s found\n", (int) number, (number == 1) ? "" : "s"); for (i = 0; i < number; i++) fprintf (fh, "%u %s\n", (unsigned int) times[i], names[i]); fflush (fh); -- 2.11.0