Process Compose

Process Compose is a simple and flexible scheduler and orchestrator to manage non-containerized applications.

Why? Because sometimes you just don't want to deal with docker files, volume definitions, networks and docker registries.

Features:

• Processes execution (in parallel or/and serially)
• Processes dependencies and startup order
• Defining recovery policies (restart on-failure, always, no). Manual recovery
• Processes arguments bash or zsh style (or define your own shell)
• Per process and global environment variables
• Per process or global (single file) logs
• Health checks (liveness and readiness)
• Terminal User Interface (TUI) or CLI modes
• Forking (services or daemons) processes
• REST API (OpenAPI a.k.a Swagger)
• Logs caching

It is heavily inspired by docker-compose, but without the need for containers. The configuration syntax tries to follow the docker-compose specifications, with a few minor additions and lots of subtractions.

Quick Start

Imaginary system diagram:

process-compose.yaml definitions for the system above:

version: "0.5"

environment:
  - "GLOBAL_ENV_VAR=1"
log_location: /path/to/combined/output/logfile.log
log_level: debug

processes:
  Manager:
    command: "/path/to/manager"
    availability:
      restart: "always"
    depends_on:
      ClientA:
        condition: process_started
      ClientB:
        condition: process_started

  ClientA:
    command: "/path/to/ClientA"
    availability:
      restart: "always"
    depends_on:
      Server_1A:
        condition: process_started
      Server_2A:
        condition: process_started
    environment:
      - "LOCAL_ENV_VAR=1"

  ClientB:
    command: "/path/to/ClientB -some -arg"
    availability:
      restart: "always"
    depends_on:
      Server_1B:
        condition: process_started
      Server_2B:
        condition: process_started
    environment:
      - "LOCAL_ENV_VAR=2"

  Server_1A:
    command: "/path/to/Server_1A"
    availability:
      restart: "always"

  Server_2A:
    command: "/path/to/Server_2A"
    availability:
      restart: "always"

  Server_1B:
    command: "/path/to/Server_1B"
    availability:
      restart: "always"

  Server_2B:
    command: "/path/to/Server_2B"
    availability:
      restart: "always"

Finally, run process-compose in the process-compose.yaml directory. Or give it a direct path:

process-compose -f /path/to/process-compose.yaml

Installation

• Go to the releases, download the package for your OS, and copy the binary to somewhere on your PATH.
• If you have the Nix package manager installed with Flake support, just run:

nix run github:F1bonacc1/process-compose

Documentation

• See examples of workflows for best practices
• See below

List of Features and Planned Features

✅ Mostly implemented

❌ Implementation not started (Your feedback and ⭐ will motivate further development 😃)

✅ Launcher

✅ Parallel

process1:
  command: "sleep 3"
process2:
  command: "sleep 3"

✅ Serial

process1:
  command: "sleep 3"
  depends_on:
    process2:
      condition: process_completed_successfully # or "process_completed" if you don't care about errors
process2:
  command: "sleep 3"
  depends_on:
    process3:
      condition: process_completed_successfully # or "process_completed" if you don't care about errors

❌ Instance Number

✅ Define process dependencies

process2:
  depends_on:
    process3:
      condition: process_completed_successfully
  process3:
    condition: process_completed_successfully

There are 4 condition types that cab be used in process dependencies:

• process_completed - is the type for waiting until a process has completed (any exit code)
• process_completed_successfully - is the type for waiting until a process has completed successfully (exit code 0)
• process_healthy - is the type for waiting until a process is healthy
• process_started - is the type for waiting until a process has started (default)

✅ Termination Parameters

nginx:
  command: "docker run --rm --name nginx_test nginx"
  shutdown:
    command: "docker stop nginx_test"
    timeout_seconds: 10 # default 10
    signal: 15 # default 15, but only if the 'command' is not defined or empty

shutdown is optional and can be omitted. The default behavior in this case: SIGTERM is issued to the running process.

In case only shutdown.signal is defined [1..31] the running process will be terminated with its value.

In case the shutdown.command is defined:

1. The shutdown.command is executed with all the Environment Variables of the primary process
2. Wait for shutdown.timeout_seconds for its completion (if not defined wait for 10 seconds)
3. In case of timeout, the process will receive the SIGKILL signal

✅ Background (detached) Processes

nginx:
  command: "docker run -d --rm --name nginx_test nginx" # note the '-d' for detached mode
  is_daemon: true # this flag is required for background processes (default false)
  shutdown:
    command: "docker stop nginx_test"
    timeout_seconds: 10 # default 10
    signal: 15 # default 15, but only if command is not defined or empty

1. For processes that start services / daemons in the background, please use the is_daemon flag set to true.

2. In case a process is daemon it will be considered running until stopped.

3. Daemon processes can only be stopped with the $PROCESSNAME.shutdown.command as in the example above.

✅ Output Handling

✅ Show process name

✅ Different colors per process

✅ StdErr is printed in Red

❌ Silence specific processes

✅ TUI (Terminal User Interface)

✅ Review processes status

✅ Start processes (only completed or disabled)

✅ Stop processes

✅ Review logs

TUI is the default run mode, but it's possible to disable it:

./process-compose -t=false

Control the UI log buffer size:

log_level: info
log_length: 1200 #default: 1000
processes:
  process2:
    command: "ls -R /"

Note: Using a too large buffer will put a significant penalty on your CPU.

✅ Logger

✅ Per Process Log Collection

process2:
  log_location: ./pc.process2.log #if undefined or empty no logs will be saved

✅ Capture StdOut output

✅ Capture StdErr output

✅ Merge into a single file

processes:
  process2:
    command: "chmod 666 /path/to/file"
environment:
  - "ABC=42"
log_location: ./pc.global.log #if undefined or empty no logs will be saved (if also not defined per process)

❌ Silence specific processes

✅ Process compose console log level

log_level: info # other options: "trace", "debug", "info", "warn", "error", "fatal", "panic"
processes:
  process2:
    command: "chmod 666 /path/to/file"

This setting controls the process-compose log level. The processes log level should be defined inside the process. It is recommended to support its definition with an environment variable that can be defined in process-compose.yaml

✅ Health Checks

Many applications running for long periods of time eventually transition to broken states, and cannot recover except by being restarted. Process Compose provides liveness and readiness probes to detect and remedy such situations.

Probes configuration and functionality are designed to work similarly to Kubernetes liveness and readiness probes.

✅ Liveness Probe

  nginx:
    command: "docker run -d --rm -p80:80 --name nginx_test nginx"
    is_daemon: true
    shutdown:
      command: "docker stop nginx_test"
      signal: 15
      timeout_seconds: 5
    liveness_probe:
      exec:
        command: "[ $(docker inspect -f '{{.State.Running}}' nginx_test) = 'true' ]"
      initial_delay_seconds: 5
      period_seconds: 2
      timeout_seconds: 5
      success_threshold: 1
      failure_threshold: 3

✅ Readiness Probe

  nginx:
    command: "docker run -d --rm -p80:80 --name nginx_test nginx"
    is_daemon: true
    shutdown:
      command: "docker stop nginx_test"
    readiness_probe:
      http_get:
        host: 127.0.0.1
        scheme: http
        path: "/"
        port: 80
      initial_delay_seconds: 5
      period_seconds: 10
      timeout_seconds: 5
      success_threshold: 1
      failure_threshold: 3

Each probe type (liveness_probe or readiness_probe) can be configured in to use one of the 2 mutually exclusive modes:

1. exec: Will run a configured command and based on the exit code decide if the process is in a correct state. 0 indicates success. Any other value indicates failure.
2. http_get: For an HTTP probe, the Process Compose sends an HTTP request to the specified path and port to perform the check. Response code 200 indicates success. Any other value indicates failure.
   • host: Host name to connect to.
   • scheme: Scheme to use for connecting to the host (HTTP or HTTPS). Defaults to HTTP.
   • path: Path to access on the HTTP server. Defaults to /.
   • port: Number of the port to access on the process. Number must be in the range 1 to 65535.

Configure Probes

Probes have a number of fields that you can use to control the behavior of liveness and readiness checks more precisely:

• initial_delay_seconds: Number of seconds after the container has started before liveness or readiness probes are initiated. Defaults to 0 seconds. The minimum value is 0.
• period_seconds: How often (in seconds) to perform the probe. Defaults to 10 seconds. The minimum value is 1.
• timeout_seconds: Number of seconds after which the probe times out. Defaults to 1 second. The minimum value is 1.
• success_threshold: Minimum consecutive successes for the probe to be considered successful after failing. Defaults to 1. Must be 1 for liveness and startup Probes. The minimum value is 1. Note: this value is not respected and was added as a placeholder for future implementation.
• failure_threshold: When a probe fails, Process Compose will try failure_threshold times before giving up. Giving up in case of liveness probe means restarting the process. In case of readiness probe, the Pod will be marked Unready. Defaults to 3. The minimum value is 1.

✅ Auto Restart if not Healthy

In order to insure that the process is restarted (and not transitioned to completed state) in case of readiness check fail, please make sure to define the availability configuration. For background (is_daemon=true) processes, the restart policy should be always.

✅ Auto Restart on Exit

process2:
  availability:
    restart: on-failure # other options: "always", "no" (default)
    backoff_seconds: 2 # default: 1
    max_restarts: 5 # default: 0 (unlimited)

✅ Environment Variables

✅ Per Process

process2:
  environment:
    - "I_AM_LOCAL_EV=42"

✅ Global

processes:
  process2:
    command: "chmod 666 /path/to/file"
  environment:
    - "I_AM_LOCAL_EV=42"
environment:
  - "I_AM_GLOBAL_EV=42"

Default environment variables:

PC_PROC_NAME - Defines the process name as defined in the process-compose.yaml file.

PC_REPLICA_NUM - Defines the process replica number. Useful for port collision avoidance for processes with multiple replicas.

✅ REST API

A convenient Swagger API is provided: http://localhost:8080/swagger/index.html

✅ Configuration

✅ Support .env file

✅ Override ${var} and $var from environment variables or .env values

❌ Merge 2 or more configuration files with override values

✅ Specify which configuration files to use

process-compose -f "path/to/process-compose-file.yaml"

✅ Auto discover configuration files

The following discovery order is used: compose.yml, compose.yaml, process-compose.yml, process-compose.yaml. If multiple files are present the first one will be used.

✅ Multi-platform

✅ Linux

The default backend is bash. You can define a different backend with a SHELL environment variable.

✅ Windows

The default backend is cmd. You can define a different backend with a SHELL environment variable.

process1:
  command: "python -c print(str(40+2))"
  #note that the same command for bash/zsh would look like: "python -c 'print(str(40+2))'"

Using powershell backend had some funky behaviour (like missing command1 && command2 functionality in older versions). If you need to run powershell scripts, use the following syntax:

process2:
  command: "powershell.exe ./test.ps1 arg1 arg2 argN"

❌ macOS

How to Contribute

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

English is not my native language, so PRs correcting grammar or spelling are welcome and appreciated.