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a17e021e SS |
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, | |
d79cbb10 | 22 | "file" => \&LogFacilityFile, |
a17e021e SS |
23 | "syslog" => \&LogFacilitySyslog, |
24 | ); | |
25 | ||
26 | ||
27 | # | |
aab61123 | 28 | ## The "Init" (Logger) function. |
a17e021e SS |
29 | # |
30 | ## This function is responsible to initialize the Logger as a class based object. | |
31 | ## It has to be called once before logging can be done. | |
32 | # | |
33 | ## The following arguments must be passed, when initializing a new Logger: | |
34 | ## "LogLevel" and "LogFacility" with valid values from above. | |
35 | # | |
aab61123 | 36 | sub Init (%) { |
a17e021e SS |
37 | my ( $class, %args ) = @_; |
38 | my $self = \%args; | |
39 | ||
40 | # Fail, if some critical arguments are missing. | |
41 | unless ((exists($self->{LogLevel})) && (exists($self->{LogFacility}))) { | |
42 | die "Could not initialize the Logger: Too less arguments are given.\n"; | |
43 | } | |
44 | ||
45 | # Use bless to make "$self" to an object of class "$class". | |
46 | bless($self, $class); | |
47 | ||
48 | # Return the class object. | |
49 | return $self; | |
50 | } | |
51 | ||
52 | # | |
53 | ## The main "Log" function. | |
54 | # | |
55 | ## This function is used to handle the messages which are generated on various | |
56 | ## points in the main programm or its modules. Those messages will contain usefull | |
57 | ## information or deeper details about errors. | |
58 | # | |
59 | ## The Log function takes care about the configured loglevel and transmitts the | |
60 | ## log messages to the configured log facility. | |
61 | # | |
62 | sub Log ($$) { | |
63 | my $self = shift; | |
64 | my ($level, $message) = @_; | |
65 | ||
66 | # Check if we got an invalid loglevel. | |
67 | unless(exists($loglevels{$level})) { | |
68 | &Log("err", "The logger has been called with an invalid loglevel ($level)!\n"); | |
69 | return; | |
70 | } | |
71 | ||
72 | # Get value for the current used loglevel. | |
73 | my $current_level = $loglevels{$self->{LogLevel}}; | |
74 | ||
75 | # Get value for the required loglevel. | |
76 | my $required_level = $loglevels{$level}; | |
77 | ||
78 | # Compare the current and required level to determine, | |
79 | # if the message should be handled. | |
80 | if ($current_level >= $required_level) { | |
81 | # Get the facility, which should be used. | |
82 | my $use_facility = $self->{LogFacility}; | |
83 | ||
84 | # Transmit log message to the correct log facility. | |
d79cbb10 | 85 | $logfacilities{$use_facility}->($self, $level, $message); |
a17e021e SS |
86 | } |
87 | } | |
88 | ||
a17e021e SS |
89 | # |
90 | ## GetLogLevels function. | |
91 | # | |
92 | ## This really simple function just returns the hash which | |
93 | ## contains all supported log levels. | |
94 | # | |
43ab646a | 95 | sub GetLogLevels () { |
a17e021e SS |
96 | # Nothing to do, just return the loglevels hash. |
97 | return %loglevels; | |
98 | } | |
99 | ||
100 | # | |
101 | ## LogFacilityConsole function. | |
102 | # | |
103 | ## This is a very simple log facility which just prints the given log | |
104 | ## message to STDOUT. | |
105 | # | |
106 | sub LogFacilityConsole ($$) { | |
d79cbb10 | 107 | my $self = shift; |
a17e021e SS |
108 | my ($type, $message) = @_; |
109 | ||
110 | # Print message on STDOUT. | |
111 | print STDOUT "\[$type\] $message\n"; | |
112 | } | |
113 | ||
114 | # | |
115 | ## LogFacilitySyslog function. | |
116 | # | |
117 | ## This log facility sends a given log message to the system log service (syslog). | |
118 | # | |
119 | sub LogFacilitySyslog ($$) { | |
d79cbb10 | 120 | my $self = shift; |
a17e021e SS |
121 | my ($type, $message) = @_; |
122 | ||
123 | # The syslog function works best with an array based input, | |
124 | # so generate one before passing the message details to syslog. | |
125 | my @syslog = ("$type", "<$type> $message"); | |
126 | ||
127 | # Establish the connection to the syslog service. | |
128 | openlog('guardian', 'cons,pid', 'user'); | |
129 | ||
130 | # Send the log message. | |
131 | syslog(@syslog); | |
132 | ||
133 | # Close the log handle. | |
134 | closelog(); | |
135 | } | |
136 | ||
d79cbb10 SS |
137 | # |
138 | ## LogFacilityFile function. | |
139 | # | |
140 | ## This log facility will write any given log messages to a specified log file. | |
141 | # | |
142 | sub LogFacilityFile ($$) { | |
143 | my $self = shift; | |
144 | my ($type, $message) = @_; | |
145 | ||
146 | # Open the logfile for writing. | |
147 | open(LOGFILE, '>>', $self->{LogFile}) or die "Could not write to $self->{LogFile}: $!\n"; | |
148 | ||
149 | # Write log message to file. | |
150 | print LOGFILE "\[$type\] $message\n"; | |
151 | ||
152 | # Close filehandle. | |
153 | close(FILE); | |
154 | } | |
155 | ||
a17e021e | 156 | 1; |