Kelper

A CLI tool to query Kubernetes pod images and their registries. Kelper helps you quickly inspect container images running in your Kubernetes clusters, with support for filtering by namespace, node, and pod name.

Features

• List all pod images in a namespace
• Filter pod images by node name
• Filter pod images by pod name
• Display image details in a clean tabular format
• Show image names and versions separately
• Identify image registries

Installation

cargo install kelper

Usage

List Pod Images in a Namespace

To list all pod images in a specific namespace:

kelper get images --namespace default

List Pod Images on a Specific Node

To list all pod images running on a specific node across all namespaces:

kelper get images -N node-name
# or
kelper get images --node node-name

Note: When using the --node flag, the --namespace parameter is ignored as it will show pods from all namespaces on the specified node.

List Images for a Specific Pod

To list images for a specific pod:

kelper get images -p pod-name
# or
kelper get images --pod pod-name

You can combine filters to get more specific results. For example, to get images for a specific pod on a specific node:

kelper get images -N node-name -p pod-name

Output Format

Kelper displays information in a clean tabular format:

Pod Images and Registries:
================================================================================
+----------------+-----------+------------+------------+---------+-------------+
| Pod Name       | Namespace | Container  | Image Name | Version | Registry    |
+----------------+-----------+------------+------------+---------+-------------+
| nginx-pod      | default   | nginx      | nginx      | latest  | docker.io   |
| redis-pod      | prod      | redis      | redis      | 6.2     | docker.io   |
| api-pod        | staging   | api        | api        | v1.0    | registry.io |
+----------------+-----------+------------+------------+---------+-------------+
================================================================================

The output includes:

• Pod Name: The name of the Kubernetes pod
• Namespace: The Kubernetes namespace
• Container: The container name within the pod
• Image Name: The name of the container image
• Version: The image version/tag
• Registry: The container registry hosting the image

Development

Prerequisites

• Rust 1.70 or later
• Kubernetes cluster access
• kubectl configured with your cluster

Building from Source

# clone kelper project
cd kelper
cargo build --release

Testing

Kelper includes comprehensive tests covering various aspects of the codebase. The tests are organized in the tests directory and include:

Image Processing Tests

• Registry extraction from various image formats
• Image name and version splitting
• Handling of different registry types (Docker Hub, GCR, Quay.io, private registries)

Pod Processing Tests

• Basic pod with multiple containers
• Pods without spec
• Pods with empty containers
• Containers without images
• Complex image paths
• Private registry images

Test Coverage

The tests cover various scenarios including:

• Edge cases (missing fields, empty values)
• Different image formats and registries
• Error conditions
• Data structure validation

To run the tests:

# Run all tests
cargo test

# Run tests with output
cargo test -- --nocapture

# Run specific test
cargo test test_process_pod

Pre-commit Hooks

This project uses pre-commit hooks to ensure code quality. To set them up:

1. Install pre-commit:

pip install pre-commit

2. Install the git hooks:

pre-commit install

The pre-commit hooks will run automatically on every commit, checking for:

• Code formatting (rustfmt)
• Linting (clippy)
• Security vulnerabilities (cargo-audit)
• And more...

License

This project is licensed under the MIT License - see the LICENSE file for details.