dove

dove

A tool for exploring a docker image, layer contents, and discovering ways to shrink the size of your Docker/OCI image.

To analyze a Docker image simply run dove with an image tag/id/digest:

dove <your-image-tag>

or you can dove with docker command directly

alias dove="docker run -ti --rm  -v /var/run/docker.sock:/var/run/docker.sock kickinranch/dove"
dove <your-image-tag>

# for example
dove nginx:latest

or if you want to build your image then jump straight into analyzing it:

dove build -t <some-tag> .

Building on Macbook (supporting only the Docker container engine)

docker run --rm -it \
      -v /var/run/docker.sock:/var/run/docker.sock \
      -v  "$(pwd)":"$(pwd)" \
      -w "$(pwd)" \
      -v "$HOME/.dove.yaml":"$HOME/.dove.yaml" \
      kickinranch/dove:latest build -t <some-tag> .

Additionally you can run this in your CI pipeline to ensure you're keeping wasted space to a minimum (this skips the UI):

CI=true dove <your-image>

This is beta quality! Feel free to submit an issue if you want a new feature or find a bug :)

Basic Features

Show Docker image contents broken down by layer

As you select a layer on the left, you are shown the contents of that layer combined with all previous layers on the right. Also, you can fully explore the file tree with the arrow keys.

Indicate what's changed in each layer

Files that have changed, been modified, added, or removed are indicated in the file tree. This can be adjusted to show changes for a specific layer, or aggregated changes up to this layer.

Estimate "image efficiency"

The lower left pane shows basic layer info and an experimental metric that will guess how much wasted space your image contains. This might be from duplicating files across layers, moving files across layers, or not fully removing files. Both a percentage "score" and total wasted file space is provided.

Quick build/analysis cycles

You can build a Docker image and do an immediate analysis with one command: dove build -t some-tag .

You only need to replace your docker build command with the same dove build command.

CI Integration

Analyze an image and get a pass/fail result based on the image efficiency and wasted space. Simply set CI=true in the environment when invoking any valid dove command.

Multiple Image Sources and Container Engines Supported

With the --source option, you can select where to fetch the container image from:

dove <your-image> --source <source>

or

dove <source>://<your-image>

With valid source options as such:

• docker: Docker engine (the default option)
• docker-archive: A Docker Tar Archive from disk
• podman: Podman engine (linux only)

Installation

Ubuntu/Debian

export dove_VERSION=$(curl -sL "https://api.github.com/repos/kickinranch/dove/releases/latest" | grep '"tag_name":' | sed -E 's/.*"v([^"]+)".*/\1/')
curl -OL https://github.com/kickinranch/dove/releases/download/v${dove_VERSION}/dove_${dove_VERSION}_linux_amd64.deb
sudo apt install ./dove_${dove_VERSION}_linux_amd64.deb

RHEL/Centos

export dove_VERSION=$(curl -sL "https://api.github.com/repos/kickinranch/dove/releases/latest" | grep '"tag_name":' | sed -E 's/.*"v([^"]+)".*/\1/')
curl -OL https://github.com/kickinranch/dove/releases/download/v${dove_VERSION}/dove_${dove_VERSION}_linux_amd64.rpm
rpm -i dove_0.9.2_linux_amd64.rpm

Arch Linux

Available in the extra repository and can be installed via pacman:

pacman -S dove

Mac

If you use Homebrew:

brew install dove

If you use MacPorts:

sudo port install dove

Or download the latest Darwin build from the releases page.

Windows

Download the latest release.

Go tools Requires Go version 1.10 or higher.

go get github.com/kickinranch/dove

Note: installing in this way you will not see a proper version when running dove -v.

Nix/NixOS

On NixOS:

nix-env -iA nixos.dove

On non-NixOS (Linux, Mac)

nix-env -iA nixpkgs.dove

Docker

docker pull kickinranch/dove

or

docker pull quay.io/kickinranch/dove

When running you'll need to include the docker socket file:

docker run --rm -it \
    -v /var/run/docker.sock:/var/run/docker.sock \
    kickinranch/dove:latest <dove arguments...>

Docker for Windows (showing PowerShell compatible line breaks; collapse to a single line for Command Prompt compatibility)

docker run --rm -it `
    -v /var/run/docker.sock:/var/run/docker.sock `
    kickinranch/dove:latest <dove arguments...>

Note: depending on the version of docker you are running locally you may need to specify the docker API version as an environment variable:

   DOCKER_API_VERSION=1.37 dove ...

or if you are running with a docker image:

docker run --rm -it \
    -v /var/run/docker.sock:/var/run/docker.sock \
    -e DOCKER_API_VERSION=1.37 \
    kickinranch/dove:latest <dove arguments...>

CI Integration

When running dove with the environment variable CI=true then the dove UI will be bypassed and will instead analyze your docker image, giving it a pass/fail indication via return code. Currently there are three metrics supported via a .dove-ci file that you can put at the root of your repo:

rules:
  # If the efficiency is measured below X%, mark as failed.
  # Expressed as a ratio between 0-1.
  lowestEfficiency: 0.95

  # If the amount of wasted space is at least X or larger than X, mark as failed.
  # Expressed in B, KB, MB, and GB.
  highestWastedBytes: 20MB

  # If the amount of wasted space makes up for X% or more of the image, mark as failed.
  # Note: the base image layer is NOT included in the total image size.
  # Expressed as a ratio between 0-1; fails if the threshold is met or crossed.
  highestUserWastedPercent: 0.20

You can override the CI config path with the --ci-config option.

KeyBindings

UI Configuration

No configuration is necessary, however, you can create a config file and override values:

# supported options are "docker" and "podman"
container-engine: docker
# continue with analysis even if there are errors parsing the image archive
ignore-errors: false
log:
  enabled: true
  path: ./dove.log
  level: info

# Note: you can specify multiple bindings by separating values with a comma.
# Note: UI hinting is derived from the first binding
keybinding:
  # Global bindings
  quit: ctrl+c
  toggle-view: tab
  filter-files: ctrl+f, ctrl+slash

  # Layer view specific bindings
  compare-all: ctrl+a
  compare-layer: ctrl+l

  # File view specific bindings
  toggle-collapse-dir: space
  toggle-collapse-all-dir: ctrl+space
  toggle-added-files: ctrl+a
  toggle-removed-files: ctrl+r
  toggle-modified-files: ctrl+m
  toggle-unmodified-files: ctrl+u
  toggle-filetree-attributes: ctrl+b
  page-up: pgup
  page-down: pgdn

diff:
  # You can change the default files shown in the filetree (right pane). All diff types are shown by default.
  hide:
    - added
    - removed
    - modified
    - unmodified

filetree:
  # The default directory-collapse state
  collapse-dir: false

  # The percentage of screen width the filetree should take on the screen (must be >0 and <1)
  pane-width: 0.5

  # Show the file attributes next to the filetree
  show-attributes: true

layer:
  # Enable showing all changes from this layer and every previous layer
  show-aggregated-changes: false

dove will search for configs in the following locations:

• $XDG_CONFIG_HOME/dove/*.yaml
• $XDG_CONFIG_DIRS/dove/*.yaml
• ~/.config/dove/*.yaml
• ~/.dove.yaml

.yml can be used instead of .yaml if desired.