Services Manager (serman)

serman is a language agnostic Windows services manager built on top of winsw. Without manual configuration at installation time, it can quickly and correctly install any app or script as a Windows service. The usage scenario is described as below.

1. The developer writes his/her app (app.js) that's meant to be deployed as a service. Along with the app, the developer writes a simple manifest file (app.xml) by running serman init app to describe the service.
2. The developer uploads the application to the machine using whatever preferable way it is.
3. The developer runs serman install app.xml to install and start the service.
4. The developer runs serman uninstall app to uninstall the service.

Quick Links

• How to install serman
• Serman command line usage
• Service configuration document
  • standard winsw features
  • serman additional features

Install

From Github Release

• Get the binary from releases
• Unzip it and invoke serman.exe from its path

From NPM

The pre-built binary is also available as an NPM package:

npm install -g serman

Usage

Usage: serman [options] [command]

Commands:

  install [options] <service-config>  install a service: serman install app.xml key1=val1,key2=val2,..
  uninstall <service_id>              uninstall a service

Options:

  -h, --help  output usage information

Benefits

Usually, it takes a lot of effort or boilerplate to write a service. With serman, all it takes in addition to the app itself is a simple manifest file, allowing the developer to better focus on the app.

An example manifest file looks like this (document):

<service>
  <id>hello</id>
  <name>hello</name>
  <description>This service runs hello continuous integration system.</description>
  <env name="NODE_ENV" value="production"/>
  <executable>node</executable>
  <arguments>"{{dir}}\hello.js"</arguments>
  <logmode>rotate</logmode>
  <persistent_env name="FOO_SERVICE_PORT" value="8989" />
</service>

serman wraps winsw. And the manifest file is used by winsw and documented here in detail. The additional features that serman adds are described below.

Serman Features

Variable Substitutions In Service Configuration

The manifest file is actually a Mustache template. Upon installing a service, serman attempts to fill every double curly brace field ({{XXX}}) with a corresponding substitution.

Currently, the supported fields are:

dir

The absolute path of the directory containing the manifest file before calling serman install.

Details: This is different than winsw's %BASE%. %BASE% is always dynamically evaluated by winsw. If it's used to specify the app path, it only works when the manifest and app are co-located. However, for ease of management (by human), serman groups all manifest files under a common top level directory (by default c:\serman\services\), while the actual locations of each app are scattered around the file system. In this case, you would want to use {{dir}} rather than %BASE%.

Additional substitutions

A powerful feature is that serman install allows you to pass in additional substitutions as an argument. This is suitable for cases you want to pass secret API key as environment variable to your app, but don't want to directly put that in the manifest.

For example, specify {{API_KEY}} in the manifest:

<!-- manifest file -->
<service>
  <id>hello</id>
  <name>hello</name>
  <description>This service runs hello continuous integration system.</description>
  <env name="API_KEY" value="{{API_KEY}}"/>
  <env name="NODE_ENV" value="{{NODE_ENV}}"/>
  <executable>node</executable>
  <arguments>"{{dir}}\hello.js"</arguments>
  <logmode>rotate</logmode>
</service>

When installing the service, run:

serman install app.xml --values API_KEY=1234_abcd,NODE_ENV=development

The installed manifest file would have:

<!-- manifest file -->
<service>
  <id>hello</id>
  <name>hello</name>
  <description>This service runs hello continuous integration system.</description>
  <env name="API_KEY" value="1234_abcd"/>
  <env name="NODE_ENV" value="development"/>
  <executable>node</executable>
  <arguments>"c:\path\to\app\hello.js"</arguments>
  <logmode>rotate</logmode>
</service>

Persistent Environment Variables

<persistent_env name="FOO" value="BAR"> can be used to add FOO=BAR as a machine-wide persistent environment variable. This is great for service discoverability where an installed service can make itself discoverable to other apps by looking at the global environment variables.

Environment variable persisting is done after the variable substitutions, so that you can use {{}} in <persistent_env>.