outtasync helps you identify Cloudformation stacks that have drifted or gone out of sync with the state represented by their template files.

tui

💾 Installation

homebrew:

brew install dhth/tap/outtasync

go:

go install github.com/dhth/outtasync@latest

Or get the binary directly from a release. Read more about verifying the authenticity of released artifacts here.

🛠️ Pre-requisites

git (used to compute diff for out-of-sync changes)
- outtasync doesn’t change or override git’s pager, so the diff will follow your .gitconfig settings (if present).

🛠️ Configuration

Create a configuration file that looks like the following. To determine where outtasync looks for this file by default on your OS, run outtasync check -h and look at the output.

stacks:
  - name: bingo-service-qa

    # use this to provide configuration and credentials via environment variables
    # https://docs.aws.amazon.com/sdkref/latest/guide/environment-variables.html
    config_source: env
    arn: arn:aws:cloudformation:eu-central-1:000000000000:stack/bingo-service-qa/00000000-1111-2222-33333333333333333
    template_path: ~/projects/bingo-service/cloudformation/infrastructure.yml
    tags:
      - qa

  - name: papaya-service-staging

    # use this to leverage a profile contained in the shared AWS config and credentials files
    # https://docs.aws.amazon.com/sdkref/latest/guide/file-format.html
    config_source: profile:<PROFILE_NAME>
    arn: arn:aws:cloudformation:eu-central-1:000000000000:stack/bingo-service-qa/00000000-4444-5555-66666666666666666
    template_path: https://url.where/your/stack/template/file/is/located/cloudformation.yml
    remote_call_headers:
      - key: Authorization
        value: "token $STACK_SPECIFIC_TOKEN"
      - key: Header
        value: "to use for sending request to the url defined by template_path"
    tags:
      - staging

  - name: galactus-service-prod

    # use this when you want to provide configuration and credentials via environment variables
    # but want to assume another role for performing the actual operations
    config_source: assume::<IAM_ROLE_ARN>
    arn: arn:aws:cloudformation:eu-central-1:000000000000:stack/galactus-service-prod/00000000-7777-8888-99999999999999999
    template_path: "$SOME_ENV_VAR/path/to/file.yml"
    tags:
      - prod

# these are applied globally to all stacks where template_path is a URL
remote_call_headers:
  - key: Authorization
    value: "token $GLOBAL_GH_TOKEN"

⚡️ Usage

outtasync provides the following subcommands:

outtasync tui: for opening up outtasync’s TUI
outtasync check: for checking for drift status and template sync status on the command line
outtasync config: for interacting with outtasync’s config

📟 TUI

$ outtasync tui -h

open outtasync's tui

Usage:
  outtasync tui [flags]

Flags:
  -c, --config-file string   location of outtasync's config file
  -h, --help                 help for tui
  -n, --name-filter string   regex for name(s) (configured in outtasync's config) to filter stacks by
  -t, --tags-filter string   regex for tag(s) to filter stacks by

tui

⌨️ TUI Keymaps

General

Keymap	What it does
`q`	go back
`esc`/`ctrl+c`	quit immediately

Stacks List

Keymap	What it does
`j`/`↓`	move cursor down
`k`/`↑`	move cursor up
`h`	go to previous page
`l`	go to next page
`g`	go to the top
`G`	go to the end
`tab`/`<S-tab>`	move between filter states
`1`	filter for stacks with code mismatch
`2`	filter for stacks that’ve drifted
`3`	filter for stacks with errors
`s`	check template sync status for stack under cursor (when unfiltered)
`S`	check template sync status for all stacks (when unfiltered)
`<ctrl+s>`	show sync check results (requires git to be available in PATH)
`d`	check drift status for stack under cursor (when unfiltered)
`D`	check drift status for all stacks (when unfiltered)
`e`	show error details (if present)

📋 Check

$ outtasync check -h

check sync and drift status for stacks

Usage:
  outtasync check [flags]

Flags:
  -D, --check-drift                 check drift status (only applicable in cli mode) (default true)
  -T, --compare-template            compare actual template with template code (only applicable in cli mode)
  -c, --config-file string          location of outtasync's config file
  -f, --format string               output format [possible values: default, delimited, html] (default "default")
  -h, --help                        help for check
  -o, --html-open                   open html output in browser instead of outputting to stdout
      --html-template-file string   location of the template file to use for html output
      --html-title string           title of the html output (default "outtasync")
  -N, --list-negatives-only         list negatives only
  -n, --name-filter string          regex for name(s) (configured in outtasync's config) to filter stacks by
  -p, --progress-indicator          whether to show progress indicator (only applicable in cli mode) (default true)
  -t, --tags-filter string          regex for tag(s) to filter stacks by

The check subcommand can output results in 3 formats: ansi colored text, delimited, and HTML.

Normal output

outtasync check -n '(customer|auth)' -T=1 -D=0

check

Delimited output

outtasync check -n '(customer|auth)' -T=1 -D=0 -f delimited | tbll

check

HTML output

outtasync check -n '(customer|auth)' -T=1 -D=0 -f html

html

🧰 Config

outtasync allows you to generate its own config.

$ outtasync config generate

generate sample config

Usage:
  outtasync config generate [flags]

Flags:
  -c, --config-source string   config source to use (default "env")
  -h, --help                   help for generate
  -n, --name-filter string     regex for name(s) to filter stacks by
  -t, --tags string            comma separated list of tags to use

You can also validate a config file using outtasync config validate.

🔐 Verifying release artifacts

In case you get the outtasync binary directly from a release, you may want to verify its authenticity. Checksums are applied to all released artifacts, and the resulting checksum file is signed using cosign.

Steps to verify (replace x.y.z in the commands listed below with the version you want):

Download the following files from the release:
- outtasync_x.y.z_checksums.txt
- outtasync_x.y.z_checksums.txt.pem
- outtasync_x.y.z_checksums.txt.sig

Verify the signature:

cosign verify-blob outtasync_x.y.z_checksums.txt \
    --certificate outtasync_x.y.z_checksums.txt.pem \
    --signature outtasync_x.y.z_checksums.txt.sig \
    --certificate-identity-regexp 'https://github\.com/dhth/outtasync/\.github/workflows/.+' \
    --certificate-oidc-issuer "https://token.actions.githubusercontent.com"

Download the compressed archive you want, and validate its checksum:

curl -sSLO https://github.com/dhth/outtasync/releases/download/vx.y.z/outtasync_x.y.z_linux_amd64.tar.gz
sha256sum --ignore-missing -c outtasync_x.y.z_checksums.txt

If checksum validation goes through, uncompress the archive:

tar -xzf outtasync_x.y.z_linux_amd64.tar.gz
./outtasync
# profit!

Changelog

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

v2.0.0 - May 07, 2025

Added

Allow checking for stack drift
Subcommand for generating config
Subcommand for validating config
HTML output for results

Changed

Changed config file schema to allow for optional template paths

Removed

Ability to refresh AWS credentials directly from the TUI