decompose

Run your stack at native speed.
decompose is a Rust process orchestrator for local development and agentic coding loops.

No image builds. No container cold starts. No bridge-network translation overhead.
Just your real processes, fast, with a familiar compose-like interface.

Installing

From crates.io

cargo install decompose

Requires Rust 1.85 or later. If you don't have Rust installed, grab it from rustup.rs.

Prebuilt binaries

Download a tarball for your platform from the latest release, extract it, and put decompose on your $PATH. Builds are published for:

Target	OS	Arch
x86_64-unknown-linux-gnu	Linux	x86_64
aarch64-unknown-linux-gnu	Linux	ARM64
x86_64-apple-darwin	macOS	Intel
aarch64-apple-darwin	macOS	Apple Silicon

Quick install example (macOS Apple Silicon):

curl -sL https://github.com/sciyoshi/decompose/releases/latest/download/decompose-aarch64-apple-darwin.tar.gz \
  | tar xz -C /usr/local/bin

With Nix

Run without installing:

nix run github:sciyoshi/decompose -- up

Or install into your profile:

nix profile install github:sciyoshi/decompose

You can also add it as a flake input in your own flake.nix:

inputs.decompose.url = "github:sciyoshi/decompose";

The flake also exposes a devShell for contributors — nix develop drops you into a shell with cargo, rustc, rustfmt, and clippy pinned.

From source

git clone https://github.com/sciyoshi/decompose
cd decompose
cargo build --release

The binary will be at target/release/decompose. You can also use cargo install --path . to install it directly into your Cargo bin directory.

Shell completions

decompose completion <shell> prints a ready-to-source completion script for bash, zsh, fish, powershell, or elvish. The bash, zsh, fish, and PowerShell scripts also do dynamic completion: on start, stop, restart, kill, logs, exec, run, and up, tab-completion pulls service names from decompose config --json, and --session / --project-name values are pulled from decompose ls --json. The helpers forward --file, -e/--env-file, --session/--project-name, and --disable-dotenv to the backing config call so completion is correct in multi-project and multi-session setups. jq is optional but recommended; without it, a sed fallback parses the JSON.

bash — add to your ~/.bashrc:

source <(decompose completion bash)

Or install system-wide once (e.g. under bash-completion):

decompose completion bash | sudo tee /etc/bash_completion.d/decompose > /dev/null

zsh — drop the script somewhere in your $fpath:

mkdir -p ~/.zfunc
decompose completion zsh > ~/.zfunc/_decompose
# then, in ~/.zshrc, before `compinit`:
#   fpath=(~/.zfunc $fpath)
#   autoload -U compinit && compinit

Or source directly in ~/.zshrc:

source <(decompose completion zsh)

fish:

decompose completion fish > ~/.config/fish/completions/decompose.fish

PowerShell — add to your $PROFILE:

decompose completion powershell | Out-String | Invoke-Expression

elvish — write to a module file and use it from rc.elv:

decompose completion elvish > ~/.config/elvish/lib/decompose.elv
# then add `use decompose` to ~/.config/elvish/rc.elv

Why this is better for day-to-day coding

• Native performance: run directly on host processes and filesystems.
• Faster inner loops: no Dockerfile rebuilds just to iterate on app code.
• Lower complexity: no container networking setup for every local workflow.
• Agent-friendly: predictable JSON/table output and deterministic control from other tabs.
• Familiar UX: up, ps, down, compose-style YAML, dependencies, replicas.

Built for humans and agents

• decompose up starts and attaches.
• Ctrl-C detaches your terminal session while keeping the daemon alive.
• decompose up -d starts and returns immediately.
• decompose ps reports empty state instead of error when nothing is running.
• Use decompose down from any tab/agent to stop the environment.

Reproducible with Nix

This repo ships a flake.nix so you can pair Nix + decompose and get most of Docker's local-dev benefits (isolated environments, consistent versions across machines) without container runtime overhead.

nix develop
cargo test

Nix pins the toolchain and dependencies; decompose orchestrates native processes on top of that reproducible environment.

Commands

decompose up [-d|--detach] [--no-deps] [SERVICE...]
decompose down
decompose ps
decompose attach
decompose logs [-f|--follow] [-n|--tail N] [SERVICE...]
decompose start [SERVICE...]
decompose stop [SERVICE...]
decompose restart [SERVICE...]

Global flags (--file, --session, -e, --disable-dotenv, --json, --table) go before the subcommand:

decompose --file compose.yml --session myproject ps --json

CLI usage examples

Basic lifecycle

# Start everything in the background
decompose up -d

# Check what is running
decompose ps

# Follow all logs
decompose logs -f

# Tear down the environment
decompose down

Starting specific services

# Start only the web and api services (dependencies are started automatically)
decompose up -d web api

# Start services without pulling in dependencies
decompose up -d --no-deps web

Managing individual services

# Stop a single service
decompose stop worker

# Start it back up
decompose start worker

# Restart one or more services
decompose restart web api

Viewing logs

# Stream logs from all services
decompose logs -f

# Show the last 100 lines from a specific service
decompose logs -n 100 web

# Follow logs for two services
decompose logs -f api worker

Multi-file configuration

# Merge a base config with development overrides
decompose --file base.yml --file dev.yml up -d

# Check status using the same file set
decompose --file base.yml --file dev.yml ps

Output modes

# Machine-readable JSON (useful in scripts and CI)
decompose ps --json

# Human-friendly table
decompose ps --table

# Pipe JSON into jq
decompose ps --json | jq '.[] | select(.status == "running")'

Session isolation

# Run two independent environments from the same directory
decompose --session staging up -d
decompose --session canary  up -d

# Inspect each independently
decompose --session staging ps
decompose --session canary  ps

# Tear down one without affecting the other
decompose --session staging down

Attaching to a running environment

# Start detached, then reattach from another terminal
decompose up -d
decompose attach

# Ctrl-C detaches without stopping the daemon

Environment files

# Load an extra env file
decompose -e secrets.env up -d

# Skip automatic .env loading
decompose --disable-dotenv up -d

Output modes

• --json: machine-readable
• --table: human-friendly
• default:
  • table when stdout is a TTY
  • table when LLM=true or CI=true
  • otherwise json

Runtime model

• Per-environment daemon, isolated by working directory + config path hash.
• Local socket IPC via interprocess.
• XDG-aware paths:
  • socket: $XDG_RUNTIME_DIR/decompose/<instance>.sock (fallbacks applied)
  • state: $XDG_STATE_HOME/decompose/<instance>.pid and .log

Configuration reference

Config file discovery

If -f/--file is omitted, decompose looks for the first matching file in the current directory:

1. decompose.yml
2. decompose.yaml
3. compose.yml
4. compose.yaml

Multiple -f flags merge with overlay semantics -- later files override earlier ones.

Quick example

processes:
  hello:
    command: "echo hello"
  date:
    command: "date"
    depends_on:
      hello:
        condition: process_completed_successfully

decompose up
decompose ps
decompose down

Global settings

These are top-level keys in the YAML file, alongside processes.

environment:            # Global env vars applied to every process
  SHARED_KEY: value

exit_mode: wait_all     # How the daemon behaves when processes exit

disable_env_expansion: false  # Disable ${VAR} interpolation globally

Field	Type	Default	Description
environment	map or list	{}	Environment variables applied to all processes. Accepts a YAML map (KEY: value) or a list of KEY=VALUE strings.
exit_mode	string	wait_all	Controls daemon behavior when processes exit. One of: wait_all (keep running until all processes finish or down is called), exit_on_failure (stop everything if any process exits non-zero), exit_on_end (stop everything when any process exits).
disable_env_expansion	bool	false	When true, disables ${VAR} interpolation in all string fields.
processes	map	required	Map of process name to process configuration. At least one process must be defined.

Process settings

Each key under processes defines a named service.

processes:
  web:
    command: "npm start"
    description: "Frontend dev server"
    working_dir: "./frontend"
    environment:
      PORT: "3000"
    env_file:
      - "frontend.env"
    disabled: false
    replicas: 1
    ready_log_line: "Listening on port \\d+"
    restart_policy: on_failure
    backoff_seconds: 2
    max_restarts: 5

Field	Type	Default	Description
command	string	required	Shell command to run. Executed via the system shell.
description	string	null	Optional human-readable description.
working_dir	string	config file directory	Working directory for the process. Relative paths resolve from the config file location.
environment	map or list	{}	Per-process environment variables. Same format as the global environment (map or list of KEY=VALUE). Merged on top of global vars.
env_file	list of strings	[]	Additional .env files to load for this process. Paths are relative to the config file directory.
disabled	bool	false	When true, the process is visible in ps output but not auto-started by up. Can be started explicitly with start.
replicas	integer	1	Number of instances to run. When greater than 1, instances are named service[1], service[2], etc. Must be at least 1.
ready_log_line	string (regex)	null	A regex pattern matched against process stdout/stderr. When a line matches, the process is marked as "log ready". Required if any other process depends on this one with process_log_ready condition.
restart_policy	string	no	Restart behavior: no (never restart), on_failure (restart on non-zero exit), always (restart on any exit).
backoff_seconds	integer	1	Delay in seconds between restart attempts.
max_restarts	integer or null	null	Maximum number of restarts. null means unlimited.

Dependencies

Use depends_on to control startup order. Each dependency names another process and a condition that must be met before the dependent process starts.

processes:
  db:
    command: "postgres -D ./data"
    readiness_probe:
      exec:
        command: "pg_isready"

  api:
    command: "cargo run"
    ready_log_line: "Listening on 0.0.0.0:8080"
    depends_on:
      db:
        condition: process_healthy

  web:
    command: "npm start"
    depends_on:
      api:
        condition: process_log_ready

Condition	Description
process_started	The dependency has been started (default if omitted).
process_completed	The dependency has exited (any exit code).
process_completed_successfully	The dependency has exited with code 0.
process_healthy	The dependency's readiness probe is passing. Requires readiness_probe to be configured on the dependency.
process_log_ready	The dependency's ready_log_line regex has matched. Requires ready_log_line to be configured on the dependency.

Circular dependencies are detected at config load time and produce an error.

Health probes

Both readiness_probe and liveness_probe share the same schema. The readiness probe sets the process's "healthy" flag (used by process_healthy dependency condition). The liveness probe restarts the process if it fails.

Each probe supports one check type: exec (run a command) or http_get (make an HTTP request).

processes:
  api:
    command: "cargo run"
    readiness_probe:
      exec:
        command: "curl -sf http://localhost:8080/health"
      period_seconds: 10
      timeout_seconds: 1
      initial_delay_seconds: 5
      success_threshold: 1
      failure_threshold: 3

    liveness_probe:
      http_get:
        host: "127.0.0.1"
        port: 8080
        scheme: http
        path: /healthz
      period_seconds: 30
      failure_threshold: 5

Probe timing fields:

Field	Type	Default	Description
period_seconds	integer	10	How often to run the check.
timeout_seconds	integer	1	Timeout for each check attempt.
initial_delay_seconds	integer	0	Delay before the first check after the process starts.
success_threshold	integer	1	Consecutive successes required to pass.
failure_threshold	integer	3	Consecutive failures required to fail.

Exec check:

Field	Type	Description
exec.command	string	Shell command to run. Exit code 0 means healthy.

HTTP check:

Field	Type	Default	Description
http_get.host	string	127.0.0.1	Host to connect to.
http_get.port	integer	required	Port number.
http_get.scheme	string	http	URL scheme (http or https).
http_get.path	string	/	Request path.

Shutdown configuration

Control how processes are stopped when decompose down, stop, or kill is called.

processes:
  worker:
    command: "python worker.py"
    shutdown:
      command: "python cleanup.py"   # Run before sending signal
      signal: 15                     # Signal number (15 = SIGTERM)
      timeout_seconds: 30            # Wait this long before SIGKILL

Field	Type	Default	Description
shutdown.command	string	null	Optional command to run before sending the stop signal.
shutdown.signal	integer	15	Signal to send to the process (15 = SIGTERM, 2 = SIGINT, etc.).
shutdown.timeout_seconds	integer	10	Seconds to wait after sending the signal before sending SIGKILL.

Environment variables

Precedence (lowest to highest)

Environment variables are merged in this order. Later sources override earlier ones:

1. .env file in the config directory (auto-loaded unless --disable-dotenv)
2. Explicit env files via -e CLI flag
3. Global environment block in the YAML
4. Per-process env_file entries
5. Per-process environment block

Variable interpolation

String fields support ${VAR} substitution from the merged environment.

Syntax	Description
${VAR}	Substitute the value of VAR. Empty string if unset.
$VAR	Same as ${VAR}.
${VAR:-default}	Substitute VAR if set, otherwise use default.
$$	Literal $ character (escape).

Interpolation is applied to these fields: command, description, working_dir, ready_log_line, shutdown.command, and all environment variable values.

Disable interpolation globally by setting disable_env_expansion: true at the top level.

Environment format

Both map and list formats are accepted anywhere environment variables are defined:

# Map format
environment:
  PORT: "3000"
  DEBUG: "true"

# List format
environment:
  - PORT=3000
  - DEBUG=true

Migrating from Docker Compose

decompose is designed to feel familiar to Docker Compose users. If you already have a docker-compose.yml, most of it can be adapted with minimal changes.

What maps directly

These fields work the same way (or very similarly) in both tools:

Docker Compose field	decompose equivalent	Notes
command	command	Runs as a native shell command instead of inside a container
environment	environment	Map or list of KEY=VALUE entries
env_file	env_file	Additional .env files to load
working_dir	working_dir	Defaults to the config file directory
depends_on	depends_on	Supports conditions: process_started, process_completed, process_completed_successfully, process_healthy, process_log_ready
healthcheck	readiness_probe / liveness_probe	Similar concept, slightly different schema (see below)
restart	restart_policy	Supports no, on_failure, always
deploy.replicas	replicas	Directly on the process definition
stop_grace_period	shutdown.timeout_seconds	Time to wait before SIGKILL
stop_signal	shutdown.signal	Signal number (e.g., 15 for SIGTERM)

What doesn't apply

Since decompose runs native processes instead of containers, these Docker Compose fields have no equivalent and should be removed:

• image -- Use command to run the process directly (e.g., node server.js, python app.py).
• build -- No container image builds. If you need a build step, add it as a separate process with a dependency.
• ports -- No port mapping needed; processes bind to host ports directly.
• volumes -- No mount translation; processes access the host filesystem natively.
• networks -- No container networking; processes communicate over localhost.
• expose, links, extra_hosts -- Not applicable.
• container_name, hostname, domainname -- Not applicable.
• entrypoint -- Fold into command.
• cap_add, cap_drop, privileged, security_opt -- Not applicable.

Config file naming

decompose auto-discovers config files in this order:

1. decompose.yml
2. decompose.yaml
3. compose.yml (same filename Docker Compose uses)
4. compose.yaml

You can keep your file named compose.yml and decompose will find it, or rename to decompose.yml to avoid ambiguity.

CLI command parity

Works the same:

Command	Notes
up [-d] [SERVICE...]	Starts services; -d detaches
down	Stops the environment
ps	Shows process status
logs [-f] [-n N] [SERVICE...]	View/follow logs
start [SERVICE...]	Start stopped services
stop [SERVICE...]	Stop running services
restart [SERVICE...]	Restart services

Not implemented (container-specific or not applicable):

build, pull, push, create, run, exec, port, top, events, images, pause, unpause, kill, cp, wait

Health check conversion

Docker Compose:

services:
  web:
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8080/health"]
      interval: 10s
      timeout: 1s
      start_period: 5s
      retries: 3

decompose:

processes:
  web:
    command: "node server.js"
    readiness_probe:
      exec:
        command: "curl -f http://localhost:8080/health"
      period_seconds: 10
      timeout_seconds: 1
      initial_delay_seconds: 5
      failure_threshold: 3

decompose also supports http_get probes as an alternative to exec:

    readiness_probe:
      http_get:
        host: "127.0.0.1"
        port: 8080
        path: /health
        scheme: http

Quick conversion checklist

1. Rename or copy your docker-compose.yml to compose.yml (or decompose.yml).
2. Remove the top-level services: key and replace it with processes: (or keep services: -- decompose uses processes:).
3. Replace image: with command: -- specify the shell command that starts each service (e.g., python manage.py runserver, npm start).
4. Remove build:, ports:, volumes:, networks:, and any other container-specific fields.
5. Keep environment:, env_file:, working_dir:, and depends_on: -- these work as-is.
6. Convert healthcheck: to readiness_probe: using the schema shown above.
7. Convert restart: to restart_policy: -- values no, on-failure/on_failure, and always are supported.
8. Convert deploy.replicas: to replicas: at the process level.
9. Test with decompose config to validate your converted file, then decompose up.

Before and after example

Docker Compose:

services:
  api:
    build: .
    ports:
      - "3000:3000"
    environment:
      DATABASE_URL: postgres://localhost/mydb
    depends_on:
      db:
        condition: service_healthy
  db:
    image: postgres:16
    volumes:
      - pgdata:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD", "pg_isready"]
      interval: 5s

volumes:
  pgdata:

decompose:

processes:
  api:
    command: "npm start"
    environment:
      DATABASE_URL: postgres://localhost/mydb
    depends_on:
      db:
        condition: process_healthy
  db:
    command: "pg_ctl start -D /usr/local/var/postgresql@16 -l db.log"
    readiness_probe:
      exec:
        command: "pg_isready"
      period_seconds: 5