Running DoDWAN on a Linux host

DoDWAN's source code is 100% Java code. It can therefore run on any platform featuring a standard JRE (Java Runtime Environment).

This code is however distributed with a bash script dodwan.sh (located in $DODWAN_HOME/bin) that makes it easy to start and stop DoDWAN on a Linux host, and to publish and receive files on this host.

Usage: dodwan.sh start
               | stop
               | status
               | clear
               | publish <desc> <fname>
               | subscribe <key> <pattern> {-d dir | -e cmd}
               | unsubscribe <key>
               | console (for experts)

Starting or stopping a DoDWAN node

dodwan.sh start
dodwan.sh stop

Note that although several DoDWAN instances could run concurrently on the same host, the bash script dodwan.sh has been designed so that only one instance shall run on each host. So if you want to test DoDWAN you will need to install it on at least two hosts.

Checking if DoDWAN is running

dodwan.sh status

Interacting with DoDWAN nodes at runtime

Publishing content

Once DoDWAN is running on the local host it can be used to publish content. The transmission data unit for this content is a message. Each message combines a descriptor (i.e. a collection of name=value pairs) and a payload.

The script makes it easy to publish the content of a file as the payload of a message:

dodwan.sh publish [desc] [fname]

where:

• desc: descriptor for the message (comma-separated list of name=value pairs)
• fname: path to the file whose content will constitute the payload of the message

Setting a subscription

A DoDWAN node can only receive messages from other nodes once a subscription has been set on that node:

dodwan.sh subscribe [key] [pattern] {options}

where:

• key: subscription key (must be unique and will be used to remove the subscription if needed)
• pattern: interest pattern (comma-separated list of name=value pairs, where values can be regular expressions)
• options: determine what to do with messages that match the pattern (optional)

Possible options are:

• -d [dir]: save a copy of the message's payload in that directory
• -e [cmd]: execute that external command

When an external command must be executed to process a message (option -e), the attributes of the message's descriptor are passed as arguments to that command, and the payload of the message is piped to the command's input stream.

Removing subscriptions

dodwan.sh unsubscribe [key]+

where:

• key: key of each subscription to be deleted

Flushing the local cache

dodwan.sh clear

Accessing the console (for experts)

Many features in DoDWAN can be controlled using its builtin console. In fact the bash script dodwan.sh is just a front-end to that console, and the set of commands it provides (start, stop, publish, subscribe, etc.) is only a subset of the possibilities offered by the console.

The full console can be accessed with:

dodwan.sh console