EnvOrigin

Explain where environment variables actually come from — in Docker Compose projects and GitHub Actions workflows.

“Why is DATABASE_URL suddenly localhost in staging? It was fine yesterday.” “Which SHARED did that step actually see — the workflow env, the job env, the step env, or the env file?”

A variable in a Compose service can be defined in five places at once — your shell, .env, --env-file, services.*.env_file, and services.*.environment — and Compose resolves each one differently depending on how the others are written. A workflow variable can be defined in five more: workflow, job, and step env: blocks, env: file: references, and GITHUB_ENV writes at runtime. When the value changes, figuring out which layer won (and which layers you just wasted an hour editing) is manual archaeology.

EnvOrigin reads your project exactly the way the platform does and answers the question per variable, with the full provenance chain and line numbers:

$ envorigin explain P -s web --show-values

P for service web
state: present
value: "compose_explicit"
winner: service environment (compose.yaml:9)
candidates:
  - [shadowed] service env_file (env/web.env:1) = "from_web_env"
  - [shadowed] service env_file (env/overrides.env:1) = "from_overrides_env"
  - [winner] service environment (compose.yaml:9) = "compose_explicit"

Values are redacted by default — you get a short SHA-256 fingerprint instead of the secret. Pass --show-values only when you mean it.

Why

Docker's own precedence rules are subtle and their failure modes are loud:

Two consequences that bite teams every week:

1. .env is not an injection layer. Values there only reach the container through ${VAR} interpolation or an unset environment: - VAR entry. Editing .env and seeing no effect is the most common false fix.
2. The winner is invisible. If environment: overrides a value from env_file, Compose gives you no hint that the env_file line is dead code. EnvOrigin marks it shadowed so you can delete it with confidence.

Install

cargo install envorigin            # crates.io
brew install FIERsity/envorigin/envorigin  # Homebrew
# or from source
cargo build --release

Requires Rust 1.86+.

Usage

EnvOrigin 0.3.0
Explain where environment variables come from

Usage: envorigin <COMMAND>

Commands:
  scan     List the variables configured for each Compose service
  explain  Explain the winning and shadowed sources for one variable
  audit    Audit a project for env health issues (sensitive values, dead code)
  diff     Compare environment drift across dotenv files
  graph    Render a mermaid provenance graph of the environment
  gitlab   Analyze a GitLab CI configuration's variables
  circleci Analyze a CircleCI configuration's environment variables
  actions  Analyze a GitHub Actions workflow's environment variables
  lsp      Start the LSP server (for editor integration)
  completions  Generate a shell completion script
  help     Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Common flags for scan/explain:

scan

$ envorigin scan

EnvOrigin 0.3.0
compose: /app/compose.yaml
docker verification: verified
interpolation files: /app/.env

service web (2 present, 4 tracked)
  D                        absent  —                        ← service environment (compose.yaml:8)
  FROM_ENV                 set     <redacted sha256:b3aa92d6> ← service environment (compose.yaml:6)
  MODE                     set     <redacted sha256:ab8e18ef> ← service environment (compose.yaml:5)

docker verification reports whether your understanding matched docker compose config --format json:

• verified — EnvOrigin's model agrees with Docker (run it on a real project and it should normally say this; if it doesn't, that's a bug — please report)
• unavailable — Docker CLI not installed; analysis is unverified
• failed — Docker ran but disagreed, with a docker-divergence diagnostic on each affected variable
• skipped — --no-docker-check was passed

explain

$ envorigin explain T -s web --show-values

T for service web
state: present
value: "from_project_env"
winner: service env_file (env/web.env:4)
derived from:
  - default .env (.env:2)

T=${S} in env/web.env interpolated S from .env — the derived from block is EnvOrigin's answer to "but why is it that value?" for interpolated variables.

actions

GitHub Actions resolves a variable from up to five declaration layers per scope, and one runtime layer you can't see statically:

$ envorigin actions explain SHARED -j build -s Configure --show-values

SHARED in workflow .github/workflows/ci.yml
state: set
value: "step_value"
winner: step env (.github/workflows/ci.yml:19)
candidates:
  - [shadowed] workflow env (.github/workflows/ci.yml:4) = "workflow_value"
  - [shadowed] job env (.github/workflows/ci.yml:11) = "job_value"
  - [winner] step env (.github/workflows/ci.yml:19) = "step_value"

actions also tracks ${{ ... }} expressions — the reference list answers "what did this value read from?" for ${{ env.X }} (resolved to its source), ${{ secrets.X }} / ${{ vars.X }} / ${{ github.* }} (marked external context, since their values live in repository/org settings), and ${{ matrix.X }} (marked external — a strategy variable). GITHUB_ENV writes like echo "RESULT=ok" >> "$GITHUB_ENV" produce an Info diagnostic: the variable exists at runtime but cannot be resolved statically.

Flags: -f/--file (default .github/workflows/ci.yml), -j/--job, -s/--step (name, id, or index), --project-directory, --show-values, --format json.

audit / actions audit / gitlab audit / circleci audit

A checkable health report for a whole project. It aggregates every diagnostic the analyzer produces, then adds checks a diagnostic model cannot express:

$ envorigin audit

EnvOrigin 0.3.0 — audit
compose: /app/compose.yaml

2 error(s), 2 warning(s), 1 info

error [sensitive-value]: API_TOKEN is set to a concrete value; verify it is not a real credential (/app/compose.yaml:7)
warning [shadowed-env-line]: SHADOWED is shadowed by a higher-precedence layer and can be removed (/app/env/web.env:2)
info [unused-interpolation-variable]: ORPHAN in the interpolation file is not consumed by any service (/app/.env:2)

--fail-on <level> (default error) turns the audit into a CI gate: --fail-on warning exits 1 when any warning or error is found. Values are never printed — the audit can run on repositories holding real credentials.

Rules (envorigin.toml)

Turn team conventions into enforced audit checks. Any audit command (audit, actions audit, gitlab audit, circleci audit) loads ./envorigin.toml automatically, or a file via --config:

# envorigin.toml
required = ["DATABASE_URL", "LOG_LEVEL"]   # must resolve somewhere
prefix = "APP_"                            # every user variable must follow
forbidden = ["CI"]                         # must not be defined

[patterns]
DATABASE_URL = "^postgres(ql)?://"         # value format validation

The same checks apply to all four backends; --fail-on gates CI exactly as for the built-in checks.

EnvOrigin audits its own workflow on every push: the Audit own workflow (dogfood) step in .github/workflows/ci.yml runs envorigin actions audit --fail-on warning on the repository's CI file.

diff

Compare dotenv files for environment drift — the same variable with different values across local, CI, and staging:

$ envorigin diff .env ci.env

EnvOrigin 0.3.0 — diff
.env vs ci.env

drift (2):
  API_TOKEN: .env = <redacted sha256:61be8cd3> | ci.env = <redacted sha256:9b723f99>
  DB_HOST: .env = "localhost" | ci.env = "db.prod.example.com"

only in .env (1):
  ONLY_LOCAL = "local_value"

Sensitive-looking variables are redacted unless --show-values is passed.

graph

A mermaid provenance graph — pipe it into mermaid-cli, mermaid.ink, or any mermaid renderer:

$ envorigin graph | mmdc -o provenance.svg

Solid edges point at the winning source, dashed edges at shadowed candidates (dashed with a derived label at interpolation dependencies). actions graph renders the workflow's job/step/variable/source layout; gitlab graph and circleci graph render the same provenance for their backends. Output has been validated against the mermaid renderer for all four.

gitlab

Layered resolution for .gitlab-ci.yml variables:: included files (include: local) < file-global < job-level. $VAR / ${VAR} interpolation is tracked per reference, and — unlike Compose — definitions may reference each other in any order (GitLab semantics), so values are resolved in a second pass over all definitions. include: remote / include: template are reported as external and not fetched. Statically-known predefined variables (CI_*, GITLAB_*, RUNNER_*) are labelled as GitLab predefined.

$ envorigin gitlab explain BUILD_ID -j build --show-values

BUILD_ID in .gitlab-ci.yml
state: set
value: "-demo"
winner: job variables (.gitlab-ci.yml:20)
references:
  - $CI_PIPELINE_ID → GitLab predefined (GitLab predefined)
  - $APP_NAME → global variables (.gitlab-ci.yml:7)

circleci

Layered resolution for .circleci/config.yml: executor environment: < job environment: / env: list. << parameters.X >> references resolve to the job's parameters: declaration (default shown); << pipeline.X >> and context: are organization/API state and are reported as external. CIRCLE_* predefined variables are labelled; values interpolate shell-style.

$ envorigin circleci explain TARGET -j build --show-values

TARGET in .circleci/config.yml
state: set
value: "<< parameters.target >>"
winner: job environment (.circleci/config.yml:21)
references:
  - parameters.target → job parameter (.circleci/config.yml:15)

lsp — editor integration

envorigin lsp speaks the Language Server Protocol over stdio and powers the VS Code extension:

• Hover a variable definition line to see its winning source and value (redacted by default).
• Go to definition jumps from a variable to the file and line that won.
• Live diagnostics mirror the audit findings — undefined interpolation references, shadowed dead-code lines, sensitive values — as you edit.

Documents are routed to the matching backend by file name (compose.y*ml, .github/workflows/*.yml, .gitlab-ci.yml, .circleci/config.yml). Unsaved buffer edits are analyzed in memory — hover and diagnostics track the buffer, while relative references still resolve against the real file location. The extension lives in vscode/ (TS client, npm run compile to build, binaryPath setting to point at the CLI).

Design

• src/compose.rs — Compose model (env_file specs, environment forms) and per-variable candidate resolution in Compose's own order.
• src/interpolation.rs — a Compose-flavored interpolator: $VAR, ${VAR}, ${VAR:-word}, ${VAR:?msg}, ${VAR:+alt}, $$ escaping, with per-reference source tracking.
• src/dotenv.rs — dotenv parsing: quoting, export prefixes, comments, unset entries, trailing-content warnings.
• src/docker.rs — spawns docker compose config --format json and reconciles Docker's canonical model against the local model.
• src/actions.rs — workflow model: layered env resolution (workflow → job → job file → step → step file), ${{ }} reference tracking, built-in default variables, and GITHUB_ENV runtime detection.
• src/output.rs — human and JSON renderers, default redaction with SHA-256 fingerprints.

Semantics notes:

• COMPOSE_ENV_FILES is expanded (path-separator split, relative to the project directory, replacing the default .env lookup); missing entries produce a compose-env-files-missing warning and are skipped. Explicit --env-file arguments take precedence over it, mirroring Docker Compose.
• COMPOSE_FILE is not followed; it produces a compose-file-redirect warning telling you to pass --file explicitly.
• actions is static analysis: GITHUB_ENV writes are flagged as runtime-only, and GitHub does not document the precedence of a file: key mixed with regular keys in one env: block — EnvOrigin applies the file layer after the map (same order as Compose env_file).

Testing

cargo test

74 tests: unit tests for the dotenv parser, the interpolator, Compose normalization, the Docker canonical extraction, the Actions layer resolution, and the audit checks; plus end-to-end CLI tests against tests/fixtures/{basic,precedence,raw,env-files,actions,actions-inputs,audit} that assert redaction, derivation tracking, the full shadowing chain, COMPOSE_ENV_FILES expansion, format: raw semantics, expression-reference resolution, and audit exit codes. CI runs fmt + clippy -D warnings + tests on Ubuntu, and audits its own workflow (dogfood).

Roadmap

Phase 1 — doctor mode (in progress)

• audit with sensitive-value, shadowed-dead-code, unused-variable checks
• --fail-on CI gate + dogfooding EnvOrigin's own workflow
• envorigin diff — compare dotenv files for environment drift (sensitive values redacted by default)
• real-repository validation: audited all 39 examples in docker/awesome-compose (every file parses and resolves; the findings fixed the placeholder and unused-variable checks). The GitLab and CircleCI backends were validated against real production configs: GitLab's own Auto-DevOps template, and leiningen's JSON-format CircleCI config.

Phase 2 — visualization & IDE (in progress)

• envorigin graph / envorigin actions graph — mermaid provenance graph (solid = winner, dashed = shadowed, dashed-derived = dependency); output validated against the mermaid renderer
• LSP server + VS Code extension (hover, go-to-definition, live diagnostics)
• GitLab CI variables support (include < global < job; $VAR reference tracking; predefined variables)
• CircleCI env support (executor < job, parameters, contexts external)

Phase 3 — ecosystem

• crates.io release (cargo install envorigin) + Homebrew tap
• rules engine: envorigin.toml for team conventions (required vars, name prefixes, value validation)
• integration notes for secret managers (Vault, AWS SSM)

Shell completions

envorigin completions bash  > ~/.bash_completion.d/envorigin
envorigin completions zsh   > ~/.zfunc/_envorigin
envorigin completions fish  > ~/.config/fish/completions/envorigin.fish

Release

./scripts/release.sh <version> tags, creates the GitHub release, publishes to crates.io, and updates the Homebrew formula in one run.

License

MIT