7 Прилагођена LLD правила

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Такође је могуће креирати потпуно прилагођено LLD правило, откривање било који тип ентитета - на пример, базе података на серверу базе података.

Да бисте то урадили, треба креирати прилагођену ставку која враћа JSON, наводећи пронађени објекти и опционо - нека њихова својства. Износ од макрои по ентитету нису ограничени - док уграђена правила откривања врати један или два макроа (на пример, два за систем датотека откриће), могуће је вратити више.

Example

The required JSON format is best illustrated with an example. Suppose we are running an old Zabbix 1.8 agent (one that does not support "vfs.fs.discovery"), but we still need to discover file systems. Here is a simple Perl script for Linux that discovers mounted file systems and outputs JSON, which includes both file system name and type. One way to use it would be as a UserParameter with key "vfs.fs.discovery_perl":

#!/usr/bin/perl
       
       $first = 1;
       
       print "[\n";
       
       for (`cat /proc/mounts`)
       {
           ($fsname, $fstype) = m/\S+ (\S+) (\S+)/;
       
           print "\t,\n" if not $first;
           $first = 0;
       
           print "\t{\n";
           print "\t\t\"{#FSNAME}\":\"$fsname\",\n";
           print "\t\t\"{#FSTYPE}\":\"$fstype\"\n";
           print "\t}\n";
       }
       
       print "]\n";

Allowed symbols for LLD macro names are 0-9 , A-Z , _ , . Lowercase letters are not supported in the names.

An example of its output (reformatted for clarity) is shown below. JSON for custom discovery checks has to follow the same format.

[
           { "{#FSNAME}":"/",                           "{#FSTYPE}":"rootfs"   },
           { "{#FSNAME}":"/sys",                        "{#FSTYPE}":"sysfs"    },
           { "{#FSNAME}":"/proc",                       "{#FSTYPE}":"proc"     },
           { "{#FSNAME}":"/dev",                        "{#FSTYPE}":"devtmpfs" },
           { "{#FSNAME}":"/dev/pts",                    "{#FSTYPE}":"devpts"   },
           { "{#FSNAME}":"/lib/init/rw",                "{#FSTYPE}":"tmpfs"    },
           { "{#FSNAME}":"/dev/shm",                    "{#FSTYPE}":"tmpfs"    },
           { "{#FSNAME}":"/home",                       "{#FSTYPE}":"ext3"     },
           { "{#FSNAME}":"/tmp",                        "{#FSTYPE}":"ext3"     },
           { "{#FSNAME}":"/usr",                        "{#FSTYPE}":"ext3"     },
           { "{#FSNAME}":"/var",                        "{#FSTYPE}":"ext3"     },
           { "{#FSNAME}":"/sys/fs/fuse/connections",    "{#FSTYPE}":"fusectl"  }
       ]

In the previous example it is required that the keys match the LLD macro names used in prototypes, the alternative is to extract LLD macro values using JSONPath {#FSNAME} → $.fsname and {#FSTYPE} → $.fstype, thus making such script possible:

#!/usr/bin/perl
        
       $first = 1;
        
       print "[\n";
        
       for (`cat /proc/mounts`)
       {
           ($fsname, $fstype) = m/\S+ (\S+) (\S+)/;
        
           print "\t,\n" if not $first;
           $first = 0;
        
           print "\t{\n";
           print "\t\t\"fsname\":\"$fsname\",\n";
           print "\t\t\"fstype\":\"$fstype\"\n";
           print "\t}\n";
       }
        
       print "]\n";

An example of its output (reformatted for clarity) is shown below. JSON for custom discovery checks has to follow the same format.

[
           { "fsname":"/",                           "fstype":"rootfs"   },
           { "fsname":"/sys",                        "fstype":"sysfs"    },
           { "fsname":"/proc",                       "fstype":"proc"     },
           { "fsname":"/dev",                        "fstype":"devtmpfs" },
           { "fsname":"/dev/pts",                    "fstype":"devpts"   },
           { "fsname":"/lib/init/rw",                "fstype":"tmpfs"    },
           { "fsname":"/dev/shm",                    "fstype":"tmpfs"    },
           { "fsname":"/home",                       "fstype":"ext3"     },
           { "fsname":"/tmp",                        "fstype":"ext3"     },
           { "fsname":"/usr",                        "fstype":"ext3"     },
           { "fsname":"/var",                        "fstype":"ext3"     },
           { "fsname":"/sys/fs/fuse/connections",    "fstype":"fusectl"  }
       ]

Then, in the discovery rule's "Filter" field, we could specify "{#FSTYPE}" as a macro and "rootfs|ext3" as a regular expression.

You don't have to use macro names FSNAME/FSTYPE with custom LLD rules, you are free to use whatever names you like. In case JSONPath is used then LLD row will be an array element that can be an object, but it can be also another array or a value.

Note that, if using a user parameter, the return value is limited to 16MB. For more details, see data limits for LLD return values.

Documentation

7 Прилагођена LLD правила

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Example