Key Facts
- Category
- Validation
- Input Types
- text
- Output Type
- text
- Sample Coverage
- 4
- API Ready
- Yes
Overview
The Docker Image Tag Validator checks if a given Docker image reference, including name and tag, adheres to Docker's official naming conventions. It helps ensure that image references are correctly formatted for use in container registries and deployments.
When to Use
- •When writing or reviewing Dockerfiles to ensure base image references are valid.
- •Before pushing images to a container registry to avoid rejection due to naming issues.
- •When debugging deployment failures that might be caused by malformed image references.
How It Works
- •Enter the Docker image reference, such as 'nginx:latest' or 'docker.io/library/ubuntu:20.04'.
- •The tool parses the reference into its components: registry, repository, tag, or digest.
- •It validates each component against Docker's official naming rules and conventions.
- •Returns a validation result indicating success or detailing any errors found.
Use Cases
Examples
1. Validating a Public Image Tag
Software Developer- Background
- A developer is setting up a new project and needs to use the official Node.js image.
- Problem
- Ensure that the image reference 'node:14-alpine' is valid and follows Docker conventions.
- How to Use
- Enter 'node:14-alpine' into the Docker Image Reference input field.
- Outcome
- The tool confirms the reference is valid, allowing the developer to proceed with confidence.
2. Checking a Complex Registry Path
- Background
- An operations engineer is configuring a deployment that uses an image from a private registry with a specific tag.
- Problem
- Validate the reference 'registry.example.com/team/app:v2.1.0-beta' to ensure it's correctly formatted.
- How to Use
- Input 'registry.example.com/team/app:v2.1.0-beta' into the tool.
- Outcome
- Validation succeeds, confirming that the registry path, repository, and tag are all compliant.
Try with Samples
imageRelated Hubs
FAQ
What is a Docker image reference?
A Docker image reference is a string that identifies a Docker image, typically in the format [registry/]repository[:tag] or [registry/]repository[@digest].
What naming rules does Docker enforce?
Repository names must be lowercase, can include dots, dashes, and underscores, and tags must consist of valid ASCII characters without spaces.
Can this tool validate image digests?
Yes, it can check references that include digests, such as 'nginx@sha256:abc123...'.
Are there length limits for image names?
Docker imposes length limits on repository names and tags; the tool verifies compliance with these limits.
What should I do if validation fails?
Review the error message provided by the tool to identify and correct the invalid part of the image reference.