Watchtower

Watchtower handles running processes, watching various targets and running commands when changes to those targets occur.

Here's a basic example of what Watchtower can do:

• On startup:
  • Build a static website
  • Run a backend server to serve the static files
• When watched files change:
  • UI file changes: re-build the static website and then restart the backend process
  • Backend file changes: restart the backend process

As Watchtower supports a variety of watch types and trigger handlers, the interactions can get more complex than this.

Installation

    git clone git@github.com:iplay88keys/watchtower

Running

From within the cloned repo:

    go run cmd/watchtower/main.go --config-file config.yml

An example config file can be found in the example config file

Config

The config file provides all the information that Watchtower needs in order to run.

The config file is defined as:

watches:
  - # ...
# - Required
# - List of watches to set up

processes:
  - # ...
# - Optional
# - List of processes to run

Watches

Watches define what needs to change in order for triggers to run.

They are defined as:

name:
# - Required
# - The name that will be used in the output when something being watched changes

config:
# - Required
# - Watch configuration

onTrigger:
  - # ...
# - Required
# - List of triggers that will be run when what is being watched changes

Watch Configs

Path Watcher

The patch watcher defines a set of directories to watch for file changes.

The config is defined as:

paths:
  - # ...
# - Required
# - List of root paths to watch for changes from
  
recursive:
# - Default: false
# - Whether to watch for file recursively from each root path
# - File changes in a directory will be watched even if recursive is false if the root is a directory
  
exclusions:
  - # ...
# - Optional
# - List of file regex patterns to ignore changes for

events:
  - # ...
# - Optional
# - List of events to watch for
# - Empty will result in all events being watched
# - Valid options are:
#   - create
#   - write
#   - remove
#   - rename
#   - chmod

Trigger Configs

Run

The run trigger will run a set of commands in order.

The config is defined as:

run:
  - # ...
# - Required
# - List of commands to run
# - Supports a limited set of templates
# - Valid templates are:
#   - {{.Name}}
#     - Replaced with the filename that changed 

continueOnError:
# - Default: false
# - Whether to continue running commands if one fails
# - If true, Watchtower will exit on a failed command run

Restart

The restart trigger will restart a process.

The config is defined as:

restart:
# - Required
# - The name of the process to restart (as defined in the processes section)

runCleanup:
# - Default: false
# - Whether to run the cleanup script 

Processes

Defines a list of processes to run on startup and can be restarted using watch triggers.

The config is defined as:

name: "frontend"
# - Required
# - The name of the process for output and trigger purposes

type: "task"
# - Required
# - Valid options:
#   - task
#     - The command is run in the foreground and waits for completion
#   - background
#     - The command is run in the background 

start:
# - Required
# - The command to run to start the process
# - Also used when restarting the process

stop:
# - Optional
# - The command to run to stop the process
# - If missing, the process will be killed if it is running
# - Also used when restarting the process

restart:
# - Optional
# - The command used to restart the process
# - Used instead of the stop and start commands when restarting a process if defined

cleanup:
# - Optional
# - The command used to clean up after stopping a process
# - Also used when restarting the process if the restart command is not provided
#   - Runs between the stop and start commands