ipwatcher - Address Watchdog

ipwatcher is a robust IPv4/IPv6 address watchdog implemented in Go. It comes equipped with event actions, notifications, and exposes a REST API, enabling seamless integration with various systems and workflows.

Installation & Usage

Installing ipwatcher is pretty straightforward, clone the repository and then run make to generate the executable:

> git clone git@github.com:gweebg/ipwatcher.git
> cd ipwatcher
> make

This should generate the executable at ipwatcher/build, with the name ipwatcher.

To use the application, just execute ipwatcher with:

> ./ipwatcher --version (v4|v6)

This will start the service and check for changes for the specified IP version according to the parameters set in the configuration file (see Configuration). You also have access to some general flags that toggle certain behaviours of the application:

Flag	Default	Description
--api	false	Enable API mode, exposing a REST service on the port specified in the configuration file.
--config <path>	config.yml	Set the path for the configuration file
--exec	true	Enable the execution of the actions defined in the configuration file.
--notify	false	Enable notifications via email.
--version <v4|v6>	v4	Set the IP version for the watcher.
--quiet	false	Set the log level to info instead of debug.

Configuring the Service

The configuration of the application is made via a YAML file, and allows configuring the different aspects that make the application stand out. By default, the service assumes the configuration path of config.yml in the root of the project, however, this behaviour can be changed by using the flag --config <config_path> when running the application.

Let's explore the configuration file, section by section.

Sources Definition

ipwatcher relies on already existing and public API's to retrieve your public address, for redundancy purposes you can define one or more fall-back alternatives, used in case of failure of the previous one.

sources:
    - field: ip
      name: "ipify"
      type: json
      url:
        v4: https://api.ipify.org?format=json
        v6: https://api6.ipify.org?format=json

    - field: ip
      name: "myip"
      type: json
      url:
        v4: https://api4.my-ip.io/v2/ip.json
        v6: https://api6.my-ip.io/v2/ip.json

On the above example, we can see that each source is defined by a set of attributes:

• name corresponds to the name of the source, names are not unique and don't need to match the actual source name
• type defines the expected response type from the API (json, text, etc.)
• field is only used when type is json and dictates the field where the address is included on the json response
• url represents both v4 and v6 versions of the API url (at least one must be included)

Note that at least one source is needed for the application to run.

Watcher Specific

watcher:

  timeout: 30 # in seconds
  force_source: "ipify" # should not be included if not used
  max_execution_time: 120 # in seconds

On the watcher section of the configuration file, you can specify execution related settings, such as:

• timeout, the time to wait between address checks (and consequently API calls)
• force_source, forces only a source (by its name) to be used
• max_execution_time, specifies the maximum time an action can be run for

Event Handling

With ipwatcher you can act upon some events, like when the address is updated on_change, when the address stays the same on_match or when an error occurs on_error. For each event you can define if you want to be notified and/or execute an action, for example, by running a Python script. My personal use-case is to update DNS records with the new address.

watcher:
  ...
  events:
    on_change:
      notify: true # true | false, enables email notifications for this action

      actions:
        - type: "python" # to execute
          path: "scripts/script.py" # what to execute 
          args: "-x" # execution arguments

    on_match:
      ...

    on_error:
      ...
  ...

Event handlers don't need to be defined, as they are completely optional. Note that event actions have, by default, 60 seconds to execute, this behaviour can be changed by updating watcher.max_execution_time.

Notification Settings

Notifications are, for now, only sent via email, thus when enabling notification for the events you need to define the smtp settings.

  smtp:
    smtp_server: "smtp.gmail.com"
    smtp_port: 587

    username: "your_username"
    password: "your_app_password"

    from_address: "example@gmail.com"

    recipients:
      - address: "person_one@gmail.com"
        name: "Person One"

      - address: "person_two@proton.me"
        name: "Person Two"

When defining the smtp settings:

• smtp_server represents the stmp server (for example, smtp.gmail.com for Gmail)
• stmp_port is the port on which the smtp_server answers
• username and password are the credentials for the smtp_server
• from_address in this case should match the username and represents the sender email address
• recipients define the recipients of the notifications, represented by their address and name (both mandatory)

API Settings

In Progress...