This is a guide for building channels with iPAM using a text editor to edit the configuration file. It is better to build configurations with Bert (see iPAM User Interfaces) but sometimes it may be necessary to revert to a plain "ole" text editor.The iPAM startup file is a text file that describes how various iPAM modules should be configured and connected. iPAM modules consist of Input agents (also known as Provider Interface Modules), Handlers (also known as Jugglers), Outputs (also known as Datacaster Interface Modules), and Daemons.
The iPAM architecture allows anything with an output to be connected to anything with an input. At present, little checking is done on the validity of a set of interconnections, so be careful. Any particular task can be described by a list of processing nodes (synonymous with iPAM modules or agents), and a list of connections between nodes.
- Daemons have no input or output
- PIMs have no input (known to iPAM) but they have an output
- DIMs have no output (known to iPAM) but they have an input
- Jugglers have both input and output
The configuration file format is a derivative of other work done at Mitre. It is a general format for describing "graphs" (nodes with connections). Nodes have a type and a unique identifier. A PIM that gets files from an FTP site is one type of node. There can be multiple instances of non-daemon modules. Currently the id of any module must uniquely identify that module. You will get unpredictable results if, for example, a PIM and a juggler instance were both given a name of "Push search."
Nodes can have several attributes depending on the type of node. For example, an email DIM requires an email address to send mail to. The Backweb DIM, on the other hand, has many attributes.
The definition of nodes, node attributes, and connectors is expressed in a simple format called Platform Independent Data Interchange Format (the acronym is PDIF for historical reasons). PDIF uses parenthesis to delimit node and connector information. A simple example of PDIF can be viewed here (with comments) or here (without comments).
Below are several examples of startup files. These examples show single and multiple channels, as well as fetches from Altavista, and output to Email and BackWeb.
PDIF Startup File Examples Example Demonstrates Ex 1 One input,handler, output; comments Ex 2 A single unchanging input delivered to an Email account Ex 3 A single unchanging input delivered to both a local window and an Email account Ex 4 Shows how to enable checkpointing, log purging, and log checking Ex 5 A single input delivered to a local BackWeb server Ex 6 An Altavista search delivered to a local BackWeb server Ex 7 FTP