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1 | package Guardian::Logger; | |
2 | use strict; | |
3 | use warnings; | |
4 | ||
5 | use Exporter qw(import); | |
6 | ||
7 | our @EXPORT_OK = qw(New Log GetLogLevels); | |
8 | ||
9 | use Sys::Syslog qw(:DEFAULT setlogsock); | |
10 | ||
11 | # Hash which stores all supported log levels and their priority. | |
12 | my %loglevels = ( | |
13 | 'off' => '0', | |
14 | 'err' => '1', | |
15 | 'info' => '1', | |
16 | 'debug' => '2', | |
17 | ); | |
18 | ||
19 | # This hash contains the supported log facilities and their corresponding subroutines. | |
20 | my %logfacilities = ( | |
21 | "console" => \&LogFacilityConsole, | |
22 | "syslog" => \&LogFacilitySyslog, | |
23 | ); | |
24 | ||
25 | ||
26 | # | |
27 | ## The "Init" (Logger) function. | |
28 | # | |
29 | ## This function is responsible to initialize the Logger as a class based object. | |
30 | ## It has to be called once before logging can be done. | |
31 | # | |
32 | ## The following arguments must be passed, when initializing a new Logger: | |
33 | ## "LogLevel" and "LogFacility" with valid values from above. | |
34 | # | |
35 | sub Init (%) { | |
36 | my ( $class, %args ) = @_; | |
37 | my $self = \%args; | |
38 | ||
39 | # Fail, if some critical arguments are missing. | |
40 | unless ((exists($self->{LogLevel})) && (exists($self->{LogFacility}))) { | |
41 | die "Could not initialize the Logger: Too less arguments are given.\n"; | |
42 | } | |
43 | ||
44 | # Use bless to make "$self" to an object of class "$class". | |
45 | bless($self, $class); | |
46 | ||
47 | # Return the class object. | |
48 | return $self; | |
49 | } | |
50 | ||
51 | # | |
52 | ## The main "Log" function. | |
53 | # | |
54 | ## This function is used to handle the messages which are generated on various | |
55 | ## points in the main programm or its modules. Those messages will contain usefull | |
56 | ## information or deeper details about errors. | |
57 | # | |
58 | ## The Log function takes care about the configured loglevel and transmitts the | |
59 | ## log messages to the configured log facility. | |
60 | # | |
61 | sub Log ($$) { | |
62 | my $self = shift; | |
63 | my ($level, $message) = @_; | |
64 | ||
65 | # Check if we got an invalid loglevel. | |
66 | unless(exists($loglevels{$level})) { | |
67 | &Log("err", "The logger has been called with an invalid loglevel ($level)!\n"); | |
68 | return; | |
69 | } | |
70 | ||
71 | # Get value for the current used loglevel. | |
72 | my $current_level = $loglevels{$self->{LogLevel}}; | |
73 | ||
74 | # Get value for the required loglevel. | |
75 | my $required_level = $loglevels{$level}; | |
76 | ||
77 | # Compare the current and required level to determine, | |
78 | # if the message should be handled. | |
79 | if ($current_level >= $required_level) { | |
80 | # Get the facility, which should be used. | |
81 | my $use_facility = $self->{LogFacility}; | |
82 | ||
83 | # Transmit log message to the correct log facility. | |
84 | $logfacilities{$use_facility}->($level, $message); | |
85 | } | |
86 | } | |
87 | ||
88 | # | |
89 | ## GetLogLevels function. | |
90 | # | |
91 | ## This really simple function just returns the hash which | |
92 | ## contains all supported log levels. | |
93 | # | |
94 | sub GetLogLevels () { | |
95 | # Nothing to do, just return the loglevels hash. | |
96 | return %loglevels; | |
97 | } | |
98 | ||
99 | # | |
100 | ## LogFacilityConsole function. | |
101 | # | |
102 | ## This is a very simple log facility which just prints the given log | |
103 | ## message to STDOUT. | |
104 | # | |
105 | sub LogFacilityConsole ($$) { | |
106 | my ($type, $message) = @_; | |
107 | ||
108 | # Print message on STDOUT. | |
109 | print STDOUT "\[$type\] $message\n"; | |
110 | } | |
111 | ||
112 | # | |
113 | ## LogFacilitySyslog function. | |
114 | # | |
115 | ## This log facility sends a given log message to the system log service (syslog). | |
116 | # | |
117 | sub LogFacilitySyslog ($$) { | |
118 | my ($type, $message) = @_; | |
119 | ||
120 | # The syslog function works best with an array based input, | |
121 | # so generate one before passing the message details to syslog. | |
122 | my @syslog = ("$type", "<$type> $message"); | |
123 | ||
124 | # Establish the connection to the syslog service. | |
125 | openlog('guardian', 'cons,pid', 'user'); | |
126 | ||
127 | # Send the log message. | |
128 | syslog(@syslog); | |
129 | ||
130 | # Close the log handle. | |
131 | closelog(); | |
132 | } | |
133 | ||
134 | 1; |