Chapter 9. Data Input Methods

Data input methods allow Cacti to retrieve data to insert into data sources and ultimately put on a graph. There are

different ways for Cacti to retrieve data, the most popular being through an external script or from SNMP.

9.1. Creating a Data Input Method

To create a new data input method, select the Data Input Methods option under the Management heading. Once on that

screen, click Add on the right. You will be presented with a few fields to populate on the following screen.

Table 9 1. Field Description: Data Input Methods

Name

Description

Name

Give the data query a name that you will use to identify it. This name will be used

throughout Cacti to identify the data input method.

Input Type

Select the type of data input method you are trying to create. Valid options here are

'Script/Command', 'SNMP', 'SNMP Query', and 'Script Query'.

Input String

This field is only used when the Input Type is set to 'Script/Command'. It specifies the

full path to the script including any per data source variables inside <>'s from the

user. For instance, if you are passing an IP address to a script, your input string might

look something like:

/path/to/script.pl 

When the user creates a data source based on this data input method, they will be

prompted for an IP address to pass onto the script.

Output String

This field is only here for legacy purposes and will probably go away in a future

version of Cacti.

When you are finished filling in all necessary fields, click the Create button to continue. You will be redirected back to

the same page, but this time with two new boxes, Input Fields and Output Fields. The Input Fields box is used to define

any fields that require information from the user. Any input fields referenced to in the input string must be defined

here. The Output Fields box is used to define each field that you expect back from the script. All data input methods must

have at least one output field defined, but may have more for a script.

9.1.1. Data Input Fields

To define a new field, click Add next to the input or output field boxes. You will be presented with some or all of the

fields below depending on whether you are adding an input or output field.

Table 9 2. Field Description: Data Input Fields

Name

Description

Field/Field Name

Either select or type in the name of the field you want to define. No spaces or other

non alphanumeric characters (except ' ' or '_') should be used in this field.

Friendly Name

Enter a more descriptive name for this field which will be used for identification

throughout Cacti.

Regular Expression Match

If you want to enforce a certain regular expression pattern when the user enters a value

(Input Only)

for this field, enter it here. The regular expression must follow POSIX syntax as it will

be passed to PHP's ereg() function.

Allow Empty Input (Input

Select whether you want to allow the user to leave the value of this field blank or not.

Only)

Special Type Code (Input

Sometimes Cacti needs to reference a field internally, but needs to rely on more than

Only)

just the field name. For instance, if your field requires an IP address from the user, you

can enter 'management_ip' here and Cacti will fill this field in with the current IP

address of the selected host. Valid values for this field are: 'hostname',

'management_ip', 'snmp_community', 'snmp_username', 'snmp_password', and

'snmp_version'.

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