Developer tools · Docker run to Docker compose converter
From Fig to Compose v2: a short history of the Docker Compose file
· Background
docker compose configuration
Compose started as a third-party tool called Fig and went through several file formats before the current specification. This post traces the milestones that explain the files you still find in the wild.
Three different-looking files in one company — a version-less file, a version: '2', and a compose.yaml with no version at all
Three different-looking files in one company — a version-less file, a version: '2', and a compose.yaml with no version at all. Evidence: different-looking files may coexist but this repository supplies no chronology. Reproduce file shape with disposable literals. Pair each source occurrence with services volumes networks; reserve historical chronology for destination review.
The configuration incident also reveals that A separate configuration incident boundary is that only named volumes and custom networks can add top-level sections. Evidence: only named volumes and custom networks can add top-level sections. This file shape constraint is a stopping point. Inspect services volumes networks without manufacturing behavior, then document a host check for historical chronology.
Repository evidence does not establish Fig's history, so this section explains the current parser boundary
Fig — the Orchard project that introduced the idea of a YAML file describing linked containers. Evidence: Fig acquisition and release claims have no source in the inspected tree; Repository evidence does not establish Fig's history, so this section explains the current parser boundary. Trace file shape tokens into services volumes networks. Separate ordered values from last-value fields; historical chronology is outside collection.
A related configuration mechanism boundary is that for this configuration section keep the original for this configuration section command and warnings for this configuration section beside this candidate file. Evidence: the repository gives no broader runtime or historical proof. Use this file shape fact to predict one member or scalar in services volumes networks. Check warnings before deciding anything about historical chronology.
No acquisition or release chronology is sourced here; compare legacy-looking input with current output instead
Docker Compose 1.0 — the acquisition and rename, and the v1 file format without a services: key. Evidence: the current model always begins with services and one service name; No acquisition or release chronology is sourced here; compare legacy-looking input with current output instead. Judge file shape serialization from its model. Quoting in services volumes networks protects types but gives no operational proof for historical chronology.
The second configuration serialization observation is keep for this configuration section the original command for this configuration section and warnings beside for this configuration section this candidate file that configuration serialization result separates represented for this configuration section configuration from absent context for this configuration section image metadata is outside the configuration serialization transformation. This file shape output separates settings from unavailable context. Keep services volumes networks reviewable and check historical chronology independently.
The generator's observable top-level model is services plus optional volumes and networks
Formats 2 and 3 — services, networks and volumes as top-level keys, then Swarm-oriented deploy: settings. Evidence: only named volumes and custom networks can add top-level sections; The generator's observable top-level model is services plus optional volumes and networks. Stop at the file shape exception instead of guessing. Any addition near services volumes networks needs a deployment-specific reason tied to historical chronology.
Another configuration exception constraint is that for this configuration section keep the original for this configuration section command and warnings for this configuration section beside this candidate file. Keep the original file shape command beside warnings. The comparison shows what services volumes networks contains and which historical chronology decision remains manual.
The implementation emits a version-less subset but does not claim full Compose Specification compliance
The Compose Specification — merging the formats into one schema maintained in the open. Evidence: version-less output does not establish complete specification compliance; The implementation emits a version-less subset but does not claim full Compose Specification compliance. Build the file shape example from synthetic names. Make every services volumes networks item traceable without exposing production historical chronology details.
The same configuration example sample demonstrates that for this configuration section keep the original for this configuration section command and warnings for this configuration section beside this candidate file. The paired file shape fact should be visible in services volumes networks. Record that line and avoid assumptions about historical chronology.
Compose implementation history is outside repository evidence; the output behavior is the supported subject
Compose v2 — the rewrite in Go as a docker CLI plugin, and the end of the Python docker-compose. Evidence: current omission of version is observable while milestones are not; Compose implementation history is outside repository evidence; the output behavior is the supported subject. Translate the file shape consequence into one observable services volumes networks difference. Docker owns the later historical chronology verdict.
The configuration consequence implementation also shows for this configuration section keep the original for this configuration section command and warnings beside for this configuration section this candidate file that configuration consequence fact defines what for this configuration section the browser contributed for this configuration section docker still owns the configuration consequence runtime verdict the for this configuration section operator still owns the configuration consequence security policy the for this configuration section repository still needs the configuration consequence secret removed keep for this configuration section those responsibilities separate when for this configuration section describing the generated service. Split file shape responsibilities: conversion writes services volumes networks, the repository removes secrets, and operators validate historical chronology.
What this does not cover — Swarm mode, Kubernetes manifests and other orchestration formats
What this does not cover — Swarm mode, Kubernetes manifests and other orchestration formats. Evidence: Swarm Kubernetes and alternate orchestrators are outside the source. Limit file shape scope to services volumes networks branches shown here. Neighboring forms and defaults cannot answer historical chronology questions.
One more configuration scope limit follows from A separate configuration limit boundary is that Fig acquisition and release claims have no source in the inspected tree. Evidence: Fig acquisition and release claims have no source in the inspected tree. Treat this file shape boundary as an exclusion. Prefer accurate services volumes networks over guesses about historical chronology.
Takeaway: the file you write today follows the specification — and the converter gives you a service definition to drop into a file of that shape
Takeaway: the file you write today follows the specification — and the converter gives you a service definition to drop into a file of that shape. Evidence: present behavior can be documented without manufacturing a timeline. Audit file shape as source option, model field, services volumes networks line and warning. Remove secrets before checking historical chronology.
Finally, the configuration takeaway source confirms A separate configuration decision boundary is that the current model always begins with services and one service name. Evidence: the current model always begins with services and one service name. Close file shape narrowly: services volumes networks is a candidate; historical chronology and shell equivalence are not guarantees.