DEV Community

Cover image for goini: Stop Writing Bash to Parse .ini Files
Andrei Merlescu
Andrei Merlescu

Posted on

goini: Stop Writing Bash to Parse .ini Files

#go #discuss #devops #tutorial

I built goenv because I was tired of writing fragile shell one-liners to work with .env files. The same problem existed with .ini files — and goini is the same answer applied there.

If you've ever written something like this in a pipeline:

grep -A 5 "^\[default\]" config.ini | grep "^user" | cut -d= -f2 | tr -d ' '
Enter fullscreen mode Exit fullscreen mode

...you know exactly why this tool exists. That breaks the moment someone adds a comment, changes indentation, or reorders keys. It's archaeology, not automation.

goini is a compiled CLI binary that lets you read, write, validate and export .ini files from your pipeline scripts. Every operation either succeeds at exit code 0 or fails at exit code 1. That makes it composable. You can gate deployments on it. You can use it in an if statement. It behaves like a Unix citizen.

The source is at github.com/andreimerlescu/goini.

Installation 

go install github.com/andreimerlescu/goini@latest
Enter fullscreen mode Exit fullscreen mode

Or grab the binary directly:

curl -sL https://github.com/andreimerlescu/goini/releases/download/v1.0.0/goini-linux-amd64 \
     --output /tmp/goini
chmod +x /tmp/goini
sudo mv /tmp/goini /usr/local/bin/goini
which goini
Enter fullscreen mode Exit fullscreen mode

The Sample File

Every example below operates against this sample.ini:

[default]
user = Yeshua
key = 369
port = 1776
country = ISRAEL

[extra]
ssh_key = ~/.ssh/id_rsa
ssh_key_pub = ~/.ssh/id_rsa.pub
Enter fullscreen mode Exit fullscreen mode

Two sections. A handful of keys. Simple on purpose — the point is showing what goini can do with it, not the data.

Validating With Exit Codes

This is the core use case for pipeline work. You don't need stdout. You need a binary answer: does this thing exist or not, and did it match or not.

Does a Section Have a Key? 

goini -ini sample.ini -section default -has-section-key user
echo $?  # 0 — key 'user' exists in 'default'

goini -ini sample.ini -section default -has-section-key non_existent_key
echo $?  # 1 — key doesn't exist
Enter fullscreen mode Exit fullscreen mode

Does a Key Have a Specific Value? 

goini -ini sample.ini -section default -key user -has-section-key-value Yeshua
echo $?  # 0

goini -ini sample.ini -section default -key user -has-section-key-value No
echo $?  # 1
Enter fullscreen mode Exit fullscreen mode

Are Multiple Sections All Present? 

goini -ini sample.ini -are-sections-present default,extra
echo $?  # 0 — both sections exist

goini -ini sample.ini -are-sections-present default,non_existent_section
echo $?  # 1 — one is missing
Enter fullscreen mode Exit fullscreen mode

Does a Section Exist? 

goini -ini sample.ini -has-section default
echo $?  # 0

goini -ini sample.ini -has-section ghost
echo $?  # 1
Enter fullscreen mode Exit fullscreen mode

Reading With STDOUT

When you need to pull data out of the file and feed it downstream, these are your commands.

List All Sections 

goini -ini sample.ini -sections
# default
# extra

goini -ini sample.ini -sections -csv
# default,extra

goini -ini sample.ini -sections -json
# [
#   "default",
#   "extra"
# ]

goini -ini sample.ini -sections -yaml
# - default
# - extra
Enter fullscreen mode Exit fullscreen mode

List Keys in a Section 

goini -ini sample.ini -section default -list-keys
# user
# key
# port
# country

goini -ini sample.ini -section default -list-keys -json
# [
#   "user",
#   "key",
#   "port",
#   "country"
# ]
Enter fullscreen mode Exit fullscreen mode

List Key-Value Pairs in a Section 

goini -ini sample.ini -section default -list-key-values
# user = Yeshua
# key = 369
# port = 1776
# country = ISRAEL

goini -ini sample.ini -section default -list-key-values -json
# {
#   "country": "ISRAEL",
#   "key": "369",
#   "port": "1776",
#   "user": "Yeshua"
# }
Enter fullscreen mode Exit fullscreen mode

Writing to the File

Add a New Section 

goini -ini sample.ini -add-section new_section
echo $?  # 0 — section added

# Try to add the same section again
goini -ini sample.ini -add-section new_section
echo $?  # 1 — already exists, refused
Enter fullscreen mode Exit fullscreen mode

This is idempotency by design. goini won't silently create a duplicate. It fails loudly so your pipeline knows something unexpected happened.

Add a Key to a Section 

goini -ini sample.ini -section default -key new_setting -value 123 -add-key
echo $?  # 0 — new_setting=123 added to [default]

# Try to add a key that already exists
goini -ini sample.ini -section default -key user -value something -add-key
echo $?  # 1 — key already exists, refused
Enter fullscreen mode Exit fullscreen mode

Again — it won't overwrite. If you need to change an existing value, that's what -modify-key is for.

Modify an Existing Key 

goini -ini sample.ini -section default -key user -value NewUserValue -modify-key
echo $?  # 0 — user updated to NewUserValue in [default]

# Try to modify a key that doesn't exist
goini -ini sample.ini -section default -key non_existent_key -value some_value -modify-key
echo $?  # 1 — key doesn't exist, refused
Enter fullscreen mode Exit fullscreen mode

The distinction between -add-key and -modify-key is intentional and important. You can't accidentally overwrite with add. You can't accidentally create with modify. They're separate operations with separate failure modes.

Real Pipeline Examples

Validating a Service Configuration Before Deploy 

#!/bin/bash
set -euo pipefail

CONFIG="infra/service.ini"

echo "==> Validating ${CONFIG}..."

# Required sections must exist
goini -ini "${CONFIG}" -are-sections-present database,cache,api \
    || { echo "ERROR: missing required sections in ${CONFIG}"; exit 1; }

# Required keys must exist in each section
goini -ini "${CONFIG}" -section database -has-section-key host \
    || { echo "ERROR: database.host is required"; exit 1; }

goini -ini "${CONFIG}" -section database -has-section-key port \
    || { echo "ERROR: database.port is required"; exit 1; }

goini -ini "${CONFIG}" -section api -has-section-key base_url \
    || { echo "ERROR: api.base_url is required"; exit 1; }

# Assert environment is correct before touching production
goini -ini "${CONFIG}" -section api -key environment -has-section-key-value staging \
    || { echo "ERROR: api.environment must be 'staging'"; exit 1; }

echo "==> Validation passed."
Enter fullscreen mode Exit fullscreen mode

Bootstrapping a Fresh Config File 

#!/bin/bash
set -euo pipefail

CONFIG="deploy.ini"

# Add sections — each will fail if already present, which is fine
# because set -euo pipefail would catch it; use || true if idempotency is needed
goini -ini "${CONFIG}" -add-section app    || true
goini -ini "${CONFIG}" -add-section database || true
goini -ini "${CONFIG}" -add-section cache  || true

# Populate app section
goini -ini "${CONFIG}" -section app -key name    -value "payments"   -add-key || true
goini -ini "${CONFIG}" -section app -key version -value "$(cat VERSION)" -add-key || true
goini -ini "${CONFIG}" -section app -key env     -value "staging"    -add-key || true

# Populate database section
goini -ini "${CONFIG}" -section database -key host    -value "db.internal" -add-key || true
goini -ini "${CONFIG}" -section database -key port    -value "5432"         -add-key || true
goini -ini "${CONFIG}" -section database -key name    -value "payments_db"  -add-key || true

# Verify it all landed
goini -ini "${CONFIG}" -section app -list-key-values
goini -ini "${CONFIG}" -section database -list-key-values
Enter fullscreen mode Exit fullscreen mode

Promoting Config From Staging to Production 

#!/bin/bash
set -euo pipefail

STAGING="config.staging.ini"
PROD="config.production.ini"

echo "==> Promoting ${STAGING} → ${PROD}..."

# Verify staging has what we expect before promoting
goini -ini "${STAGING}" -section app -key env -has-section-key-value staging \
    || { echo "ERROR: source must be staging"; exit 1; }

# Flip the environment value in production
goini -ini "${PROD}" -section app -key env -value production -modify-key \
    || { echo "ERROR: failed to set env=production"; exit 1; }

# Confirm
goini -ini "${PROD}" -section app -key env -has-section-key-value production \
    && echo "==> Promotion complete." \
    || { echo "ERROR: production env value not confirmed"; exit 1; }
Enter fullscreen mode Exit fullscreen mode

Extracting Values for Use in Other Scripts 

#!/bin/bash
set -euo pipefail

CONFIG="service.ini"

# Pull values out and assign to shell variables
DB_HOST=$(goini -ini "${CONFIG}" -section database -list-key-values -json \
    | python3 -c "import sys,json; print(json.load(sys.stdin)['host'])")

DB_PORT=$(goini -ini "${CONFIG}" -section database -list-key-values -json \
    | python3 -c "import sys,json; print(json.load(sys.stdin)['port'])")

echo "Connecting to ${DB_HOST}:${DB_PORT}"
Enter fullscreen mode Exit fullscreen mode

GitHub Actions 

name: Deploy

on:
  push:
    branches: [main]

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install goini
        run: |
          curl -sL https://github.com/andreimerlescu/goini/releases/download/v1.0.0/goini-linux-amd64 \
               --output /usr/local/bin/goini
          chmod +x /usr/local/bin/goini

      - name: Validate config
        run: |
          goini -ini config/service.ini -are-sections-present app,database,cache || exit 1
          goini -ini config/service.ini -section app -has-section-key version     || exit 1
          goini -ini config/service.ini -section app -key env -has-section-key-value staging || exit 1

      - name: Deploy
        run: ./scripts/deploy.sh
Enter fullscreen mode Exit fullscreen mode

GitLab CI 

stages:
  - validate
  - deploy

validate_config:
  stage: validate
  image: golang:1.22
  before_script:
    - curl -sL https://github.com/andreimerlescu/goini/releases/download/v1.0.0/goini-linux-amd64
           --output /usr/local/bin/goini
    - chmod +x /usr/local/bin/goini
  script:
    - goini -ini config/service.ini -are-sections-present app,database || exit 1
    - goini -ini config/service.ini -section database -has-section-key host || exit 1
    - goini -ini config/service.ini -section app -key env -has-section-key-value staging || exit 1
Enter fullscreen mode Exit fullscreen mode

Complete Flag Reference

Flag Type Description
-ini string Required. Path to the .ini file
-section string Section name for scoped operations
-sections bool List all sections in the file
-add-section string Add a new section. Fails if already present
-has-section string Exit 0 if section exists, 1 if not
-has-section-key string Exit 0 if key exists in -section
-has-section-key-value string Exit 0 if key in -section equals this value. Requires -key
-are-sections-present string Comma-separated list. Exit 0 if all present
-key string Key name for value operations
-value string Value for write or comparison operations
-add-key bool Add -key=-value to -section. Fails if key exists
-modify-key bool Update existing -key in -section. Fails if key absent
-list-keys bool Print all keys in -section to stdout
-list-key-values bool Print all key=value pairs in -section to stdout
-csv bool Output as CSV
-json bool Output as JSON
-yaml bool Output as YAML

A Few Things Worth Knowing

-add-key and -modify-key are intentionally separate. You can't accidentally overwrite an existing value with -add-key — it refuses. You can't accidentally create a new key with -modify-key — it refuses. They each have one job and one failure mode. That's the point.

-add-section is idempotent-safe. Adding a section that already exists exits with code 1. In a pipeline where you need true idempotency, pipe it with || true. In a pipeline where you want to catch unexpected state, let it fail.

-are-sections-present takes a comma-separated list. All sections must be present for exit code 0. One missing section fails the whole check.

Output format flags work with read operations. -csv, -json, and -yaml apply to -sections, -list-keys, and -list-key-values. They don't apply to write operations — those just use the exit code.

Every write operation reads the file, modifies the result in memory, and writes it back. There's no in-place line editing. This means the file that comes out is clean and predictable regardless of what formatting the original had.

The source and releases are at github.com/andreimerlescu/goini. Apache 2.0.

Top comments (0)