go-serviceman/README.md

go-serviceman

A cross-platform service manager.

Because debugging launchctl, systemd, etc absolutely sucks!

...and I wanted a reasonable way to install Telebit on Windows. (see more in the Why section below)

Features

• Unprivileged (User Mode) Services
  • Linux (sytemctl --user)
  • MacOS (launchctl)
  • Windows (HKEY_CURRENT_USER/.../Run)
• Privileged (System) Services
  • Linux (sudo sytemctl)
  • MacOS (sudo launchctl)
  • Windows (not yet implemented)

Table of Contents

• Usage
• Install
• Examples
  • compiled programs
  • scripts
  • bash
  • node
  • python
  • ruby
• Logging
• Debugging
• Windows
• Building
• Why
• Legal

Usage

The basic pattern of usage, and what that might look like:

serviceman add [options] [interpreter] <service> -- [service options]

serviceman add foo.exe

serviceman add --title "Foo App" node ./foo.js -- --bar

You can also view the help and the version:

serviceman add --help

serviceman version

Install

There are a number of pre-built binaries.

If none of them work for you, or you prefer to build from source, see the instructions for building far down below.

Downloads

MacOS

MacOS (darwin): 64-bit Download

curl https://rootprojects.org/serviceman/dist/darwin/amd64/serviceman -o serviceman

Windows

See download options

Windows 10: [64-bit Download](https://rootprojects.org/serviceman/dist/windows/amd64/serviceman.exe)

powershell.exe $ProgressPreference = 'SilentlyContinue'; Invoke-WebRequest https://rootprojects.org/serviceman/dist/windows/amd64/serviceman.exe -OutFile serviceman.exe

Debug version:

powershell.exe $ProgressPreference = 'SilentlyContinue'; Invoke-WebRequest https://rootprojects.org/serviceman/dist/windows/amd64/serviceman.debug.exe -OutFile serviceman.debug.exe

Windows 7: 32-bit Download

powershell.exe "(New-Object Net.WebClient).DownloadFile('https://rootprojects.org/serviceman/dist/windows/386/serviceman.exe', 'serviceman.exe')"

Debug version:

powershell.exe "(New-Object Net.WebClient).DownloadFile('https://rootprojects.org/serviceman/dist/windows/386/serviceman.debug.exe', 'serviceman.debug.exe')"

Linux

See download options

Linux (64-bit): Download

curl https://rootprojects.org/serviceman/dist/linux/amd64/serviceman -o serviceman

Linux (32-bit): Download

curl https://rootprojects.org/serviceman/dist/linux/386/serviceman -o serviceman

Raspberry Pi (Linux ARM)

See download options

RPi 4 (64-bit armv8): Download

curl https://rootprojects.org/serviceman/dist/linux/armv8/serviceman -o serviceman`

RPi 3 (armv7): Download

curl https://rootprojects.org/serviceman/dist/linux/armv7/serviceman -o serviceman

ARMv6: Download

curl https://rootprojects.org/serviceman/dist/linux/armv6/serviceman -o serviceman

RPi Zero (armv5): Download

curl https://rootprojects.org/serviceman/dist/linux/armv5/serviceman -o serviceman

Add to PATH

Windows

mkdir %userprofile%\bin
reg add HKEY_CURRENT_USER\Environment /v PATH /d "%PATH%;%userprofile%\bin"
move serviceman.exe %userprofile%\bin\serviceman.exe

All Others

chmod a+x ./serviceman
sudo mv ./serviceman /usr/local/bin/

Examples

serviceman add <program> -- <program options>

Compiled Programs

Normally you might your program somewhat like this:

dinglehopper --port 8421

Adding a service for that program with serviceman would look like this:

serviceman add dinglehopper -- --port 8421

serviceman will find dinglehopper in your PATH.

Using with scripts

Although your text script may be executable, you'll need to specify the interpreter in order for serviceman to configure the service correctly.

For example, if you had a bash script that you normally ran like this:

./snarfblat.sh --port 8421

You'd create a system service for it like this:

serviceman add bash ./snarfblat.sh -- --port 8421

serviceman will resolve ./snarfblat.sh correctly because it comes before the --.

Background Information

An operating system can't "run" text files (even if the executable bit is set).

Scripts require an interpreter. Often this is denoted at the top of "executable" scripts with something like one of these:

#!/usr/bin/env ruby

#!/usr/bin/python

However, sometimes people get fancy and pass arguments to the interpreter, like this:

#!/usr/local/bin/node --harmony --inspect

Using with node.js

If normally you run your node script something like this:

node ./demo.js --foo bar --baz

Then you would add it as a system service like this:

serviceman add node ./demo.js -- --foo bar --baz

It is important that you specify node ./demo.js and not just ./demo.js

See Using with scripts for more detailed information.

Using with python

If normally you run your python script something like this:

python ./demo.py --foo bar --baz

Then you would add it as a system service like this:

serviceman add python ./demo.py -- --foo bar --baz

It is important that you specify python ./demo.py and not just ./demo.py

See Using with scripts for more detailed information.

Using with ruby

If normally you run your ruby script something like this:

ruby ./demo.rb --foo bar --baz

Then you would add it as a system service like this:

serviceman add ruby ./demo.rb -- --foo bar --baz

It is important that you specify ruby ./demo.rb and not just ./demo.rb

See Using with scripts for more detailed information.

Relative vs Absolute Paths

Although serviceman can expand the executable's path, if you have any arguments with relative paths you should switch to using absolute paths.

dinglehopper --config ./conf.json

serviceman add dinglehopper -- --config /Users/me/dinglehopper/conf.json

Logging

When you run serviceman add it will either give you an error or will print out the location where logs will be found.

By default it's one of these:

~/.local/share/<NAME>/var/log/<NAME>.log

/var/log/<NAME>/var/log/<NAME>.log

You set it with one of these:

• --logdir <path> (cli)
• "logdir": "<path>" (json)
• Logdir: "<path>" (go)

If anything about the logging sucks, tell me... unless they're your logs (which they probably are), in which case you should fix them.

That said, my goal is that it shouldn't take an IT genius to interpret why your app failed to start.

Debugging

One of the most irritating problems with all of these launchers is that they're terrible to debug - it's often difficult to find the logs, and nearly impossible to interpret them, if they exist at all.

The config files generate by serviceman are simple, template-generated and tested, and therefore gauranteed to work - if your application runs with the parameters given, which is big 'if'.

serviceman tries to make sure that all necessary files and folders exist and give clear error messages if they don't (be sure to check the logs, mentioned above).

There's also a run utility that can be used to test that the parameters you've given are being interpreted correctly (absolute paths and such).

serviceman run --config ./conf.json

Where conf.json looks something like

For Binaries:

{
  "title": "Demo",
  "exec": "/Users/me/go-demo/demo",
  "argv": ["--foo", "bar", "--baz", "qux"]
}

For Scripts:

Scripts can't be run directly. They require a binary interpreter - bash, node, ruby, python, etc.

If you're running from the folder containing ./demo.js, and node.exe is in your PATH, then you can use executable names and relative paths.

{
  "title": "Demo",
  "interpreter": "node.exe",
  "exec": "./bin/demo.js",
  "argv": ["--foo", "bar", "--baz", "qux"]
}

That's equivalent to this:

{
  "title": "Demo",

  "name": "demo",

  "exec": "node.exe",
  "argv": ["./bin/demo.js", "--foo", "bar", "--baz", "qux"]
}

Making add and run take the exact same arguments is on the TODO list. The fact that they don't is an artifact of run being created specifically for Windows.

If you have gripes about it, tell me. It shouldn't suck. That's the goal anyway.

Peculiarities of Windows

Console vs No Console

Windows binaries can be built either for the console or the GUI.

When they're built for the console they can hide themselves when they start. They must open up a terminal window.

When they're built for the GUI they can't print any output - even if they're started in the terminal.

This is why there's a Debug version for the windows binaries - so that you can get your arguments correct with the one and then switch to the other.

There's probably a clever way to work around this, but I don't know what it is yet.

No userspace launcher

Windows doesn't have a userspace daemon launcher. This means that if your application crashes, it won't automatically restart.

However, serviceman handles this by not directly adding your application to HKEY_CURRENT_USER/.../Run, but rather installing a copy of itself instead, which runs your application and automatically restarts it whenever it exits.

If the application fails to start serviceman will retry continually, but it does have an exponential backoff of up to 1 minute between failed restart attempts.

See the bit on serviceman run in the Debugging section up above for more information.

Building

git clone https://git.coolaj86.com/coolaj86/go-serviceman.git

pushd ./go-serviceman

go generate -mod=vendor ./...

Windows:

go build -mod=vendor -ldflags "-H=windowsgui" -o serviceman.exe

Linux, MacOS:

go build -mod=vendor -o /usr/local/bin/serviceman

Why

I created this for two reasons:

1. Too often I just run services in screen -xRS foo because systemd .service files are way too hard to get right and even harder to debug. I make stupid typos or config mistakes and get it wrong. Then I get a notice 18 months later from digital ocean that NYC region 3 is being rebooted and to expect 5 seconds of downtime... and I don't remember if I remembered to go back and set up that service with systemd or not.
2. To make it easier for people to install Telebit on Windows.

Legal

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Copyright 2019 AJ ONeal.