From ae49fdda74a72f9fea596dba4f0470163f28d4b5 Mon Sep 17 00:00:00 2001 From: Dmytro Lytovchenko Date: Tue, 4 Jul 2017 15:21:26 +0200 Subject: Disksup parsing for 'df' output on POSIX and SUSv3 systems Tests for disksup:parse_df --- lib/os_mon/src/disksup.erl | 98 +++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 93 insertions(+), 5 deletions(-) (limited to 'lib/os_mon/src/disksup.erl') diff --git a/lib/os_mon/src/disksup.erl b/lib/os_mon/src/disksup.erl index 492e4814da..36730aac74 100644 --- a/lib/os_mon/src/disksup.erl +++ b/lib/os_mon/src/disksup.erl @@ -32,7 +32,7 @@ terminate/2, code_change/3]). %% Other exports --export([format_status/2]). +-export([format_status/2, parse_df/2]). -record(state, {threshold, timeout, os, diskdata = [],port}). @@ -294,8 +294,8 @@ check_disks_solaris("", _Threshold) -> check_disks_solaris("\n", _Threshold) -> []; check_disks_solaris(Str, Threshold) -> - case io_lib:fread("~s~d~d~d~d%~s", Str) of - {ok, [_FS, KB, _Used, _Avail, Cap, MntOn], RestStr} -> + case parse_df(Str, posix) of + {ok, {KB, Cap, MntOn}, RestStr} -> if Cap >= Threshold -> set_alarm({disk_almost_full, MntOn}, []); @@ -308,14 +308,102 @@ check_disks_solaris(Str, Threshold) -> check_disks_solaris(skip_to_eol(Str),Threshold) end. +%% @private +%% @doc Predicate to take a word from the input string until a space or +%% a percent '%' sign (the Capacity field is followed by a %) +parse_df_is_not_space($ ) -> false; +parse_df_is_not_space($%) -> false; +parse_df_is_not_space(_) -> true. + +%% @private +%% @doc Predicate to take spaces away from string. Stops on a non-space +parse_df_is_space($ ) -> true; +parse_df_is_space(_) -> false. + +%% @private +%% @doc Predicate to consume remaining characters until end of line. +parse_df_is_not_eol($\r) -> false; +parse_df_is_not_eol($\n) -> false; +parse_df_is_not_eol(_) -> true. + +%% @private +%% @doc Trims leading non-spaces (the word) from the string then trims spaces. +parse_df_skip_word(Input) -> + Remaining = lists:dropwhile(fun parse_df_is_not_space/1, Input), + lists:dropwhile(fun parse_df_is_space/1, Remaining). + +%% @private +%% @doc Takes all non-spaces and then drops following spaces. +parse_df_take_word(Input) -> + {Word, Remaining0} = lists:splitwith(fun parse_df_is_not_space/1, Input), + Remaining1 = lists:dropwhile(fun parse_df_is_space/1, Remaining0), + {Word, Remaining1}. + +%% @private +%% @doc Takes all non-spaces and then drops the % after it and the spaces. +parse_df_take_word_percent(Input) -> + {Word, Remaining0} = lists:splitwith(fun parse_df_is_not_space/1, Input), + %% Drop the leading % or do nothing + Remaining1 = case Remaining0 of + [$% | R1] -> R1; + _ -> Remaining0 % Might be no % or empty list even + end, + Remaining2 = lists:dropwhile(fun parse_df_is_space/1, Remaining1), + {Word, Remaining2}. + +%% @private +%% @doc Given a line of 'df' POSIX/SUSv3 output split it into fields: +%% a string (mounted device), 4 integers (kilobytes, used, available +%% and capacity), skip % sign, (optionally for susv3 can also skip IUsed, IFree +%% and ICap% fields) then take remaining characters as the mount path +-spec parse_df(string(), posix | susv3) -> + {error, parse_df} | {ok, {integer(), integer(), integer()}, string()}. +parse_df(Input0, Flavor) -> + %% Format of Posix/Linux df output looks like Header + Lines + %% Filesystem 1024-blocks Used Available Capacity Mounted on + %% udev 2467108 0 2467108 0% /dev + Input1 = parse_df_skip_word(Input0), % skip device path field + {KbStr, Input2} = parse_df_take_word(Input1), % take Kb field + Input3 = parse_df_skip_word(Input2), % skip Used field + Input4 = parse_df_skip_word(Input3), % skip Avail field + + % take Capacity% field; drop a % sign following the capacity + {CapacityStr, Input5} = parse_df_take_word_percent(Input4), + + %% Format of OS X/SUSv3 df looks similar to POSIX but has 3 extra columns + %% Filesystem 1024-blocks Used Available Capacity iused ifree %iused Mounted + %% /dev/disk1 243949060 2380 86690680 65% 2029724 37555 0% / + Input6 = case Flavor of + posix -> Input5; + susv3 -> % there are 3 extra integers we want to skip + Input5a = parse_df_skip_word(Input5), % skip IUsed field + Input5b = parse_df_skip_word(Input5a), % skip IFree field + %% skip the value of ICap + '%' field + {_, Input5c} = parse_df_take_word_percent(Input5b), + Input5c + end, + + % path is the remaining string till end of line + {MountPath, Input7} = lists:splitwith(fun parse_df_is_not_eol/1, Input6), + % Trim the newlines + Remaining = lists:dropwhile(fun(X) -> not parse_df_is_not_eol(X) end, + Input7), + try + Kb = erlang:list_to_integer(KbStr), + Capacity = erlang:list_to_integer(CapacityStr), + {ok, {Kb, Capacity, MountPath}, Remaining} + catch error:badarg -> + {error, parse_df} + end. + % Parse per SUSv3 specification, notably recent OS X check_disks_susv3("", _Threshold) -> []; check_disks_susv3("\n", _Threshold) -> []; check_disks_susv3(Str, Threshold) -> - case io_lib:fread("~s~d~d~d~d%~d~d~d%~s", Str) of - {ok, [_FS, KB, _Used, _Avail, Cap, _IUsed, _IFree, _ICap, MntOn], RestStr} -> + case parse_df(Str, susv3) of + {ok, {KB, Cap, MntOn}, RestStr} -> if Cap >= Threshold -> set_alarm({disk_almost_full, MntOn}, []); -- cgit v1.2.3