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 +++++++++++++++++++++++++++++++++++++-- lib/os_mon/test/disksup_SUITE.erl | 38 ++++++++++++++- 2 files changed, 129 insertions(+), 7 deletions(-) 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}, []); diff --git a/lib/os_mon/test/disksup_SUITE.erl b/lib/os_mon/test/disksup_SUITE.erl index ad61985014..d7f2626160 100644 --- a/lib/os_mon/test/disksup_SUITE.erl +++ b/lib/os_mon/test/disksup_SUITE.erl @@ -30,7 +30,7 @@ -export([port/1]). -export([terminate/1, unavailable/1, restart/1]). -export([otp_5910/1]). --export([posix_only/1]). +-export([posix_only/1, parse_df_output_posix/1, parse_df_output_susv3/1]). init_per_suite(Config) when is_list(Config) -> ok = application:start(os_mon), @@ -59,7 +59,8 @@ suite() -> all() -> Bugs = [otp_5910], - Always = [api, config, alarm, port, posix_only, unavailable] ++ Bugs, + Always = [api, config, alarm, port, posix_only, unavailable, + parse_df_output_posix, parse_df_output_susv3] ++ Bugs, case test_server:os_type() of {unix, _OSname} -> Always; {win32, _OSname} -> Always; @@ -413,3 +414,36 @@ get_disk_data([{"none",0,0}=E]) -> [E]; get_disk_data([{_,_,0}|Es]) -> get_disk_data(Es); get_disk_data([E|Es]) -> [E|get_disk_data(Es)]; get_disk_data([]) -> []. + +%% @doc Test various expected inputs to 'df' command output (Linux/POSIX) +parse_df_output_posix(Config) when is_list(Config) -> + PosixHdr = "Filesystem 1K-blocks Used Available Use% Mounted on\n", + {error, _} = disksup:parse_df(PosixHdr, posix), + {error, _} = disksup:parse_df("", posix), + {error, _} = disksup:parse_df("\n\n", posix), + + %% Have a simple example with no funny spaces in mount path + Posix1 = "tmpfs 498048 7288 490760 2% /run\n", + {ok, {498048, 2, "/run"}, ""} = disksup:parse_df(Posix1, posix), + + %% Have a mount path with some spaces in it + Posix2 = "tmpfs 498048 7288 490760 2% /spaces 1 2\n", + {ok, {498048, 2, "/spaces 1 2"}, ""} = disksup:parse_df(Posix2, posix). + +%% @doc Test various expected inputs to 'df' command output (Darwin/SUSv3) +parse_df_output_susv3(Config) when is_list(Config) -> + DarwinHdr = "Filesystem 1024-blocks Used Available Capacity " ++ + "iused ifree %iused Mounted on", + {error, _} = disksup:parse_df(DarwinHdr, susv3), + {error, _} = disksup:parse_df("", susv3), + {error, _} = disksup:parse_df("\n\n", susv3), + + %% Have a simple example with no funny spaces in mount path + Darwin1 = "/dev/disk1 243949060 157002380 86690680 65% 2029724 " ++ + "4292937555 0% /\n", + {ok, {243949060, 65, "/"}, ""} = disksup:parse_df(Darwin1, susv3), + + %% Have a mount path with some spaces in it + Darwin2 = "/dev/disk1 243949060 157002380 86690680 65% 2029724 " ++ + "4292937555 0% /spaces 1 2\n", + {ok, {243949060, 65, "/spaces 1 2"}, ""} = disksup:parse_df(Darwin2, susv3). -- cgit v1.2.3