Docker Image Reference Regex Pattern
Validates Docker image references including registry, repository, tag, and digest components.
Live Regex Tester
Pattern Breakdown
Code Examples
JavaScript
const regex = /^(?:([a-z0-9]+(?:[._-][a-z0-9]+)*)\/)?([a-z0-9]+(?:[._-][a-z0-9]+)*)(?::([a-zA-Z0-9][a-zA-Z0-9._-]{0,127}))?(?:@sha256:[a-fA-F0-9]{64})?$/;
const test = "nginx:latest";
console.log(regex.test(test)); // true
// Extract matches
const matches = test.match(regex);
console.log(matches);Python
import re
pattern = r'^(?:([a-z0-9]+(?:[._-][a-z0-9]+)*)\/)?([a-z0-9]+(?:[._-][a-z0-9]+)*)(?::([a-zA-Z0-9][a-zA-Z0-9._-]{0,127}))?(?:@sha256:[a-fA-F0-9]{64})?$'
test = "nginx:latest"
match = re.search(pattern, test)
print(match) # Found!Go
package main
import (
"fmt"
"regexp"
)
func main() {
re := regexp.MustCompile(`^(?:([a-z0-9]+(?:[._-][a-z0-9]+)*)\/)?([a-z0-9]+(?:[._-][a-z0-9]+)*)(?::([a-zA-Z0-9][a-zA-Z0-9._-]{0,127}))?(?:@sha256:[a-fA-F0-9]{64})?$`)
fmt.Println(re.MatchString("nginx:latest")) // true
}Common Use Cases
Match Examples
| Input | Result |
|---|---|
| nginx:latest | Match |
| NGINX:Latest | No Match |
About the Docker Image Reference Regex
Validates Docker image references including registry, repository, tag, and digest components.
Regular expressions (regex) are powerful pattern matching tools used across virtually all programming languages. The docker image reference pattern is classified as advanced difficulty in the devops category. It works in all major programming languages.
When using this regex, always consider edge cases and test thoroughly with real-world data. Use the interactive tester above to validate the pattern against your specific inputs before deploying to production.
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Frequently Asked Questions
What is the Docker Image Reference regex pattern?
Validates Docker image references including registry, repository, tag, and digest components.
How do I use the Docker Image Reference regex?
Use the pattern /^(?:([a-z0-9]+(?:[._-][a-z0-9]+)*)\/)?([a-z0-9]+(?:[._-][a-z0-9]+)*)(?::([a-zA-Z0-9][a-zA-Z0-9._-]{0,127}))?(?:@sha256:[a-fA-F0-9]{64})?$/ in your code. In JavaScript: new RegExp('^(?:([a-z0-9]+(?:[._-][a-z0-9]+)*)\/)?([a-z0-9]+(?:[._-][a-z0-9]+)*)(?::([a-zA-Z0-9][a-zA-Z0-9._-]{0,127}))?(?:@sha256:[a-fA-F0-9]{64})?$', ''). Test it above with your own input.
What does this Docker Image Reference regex match?
This pattern matches: "nginx:latest". It does NOT match: "NGINX:Latest". Container deployment, CI/CD pipelines, registry management.
Is the Docker Image Reference regex beginner-friendly?
This pattern is rated Advanced. It uses advanced features like lookaheads, backreferences, or complex alternation.
What languages support the Docker Image Reference regex?
This pattern works in all major programming languages including JavaScript, Python, Java, C#, Go, Ruby, PHP, and more. Syntax may vary slightly between regex engines.
Can I modify the Docker Image Reference regex for my use case?
Yes! Use the interactive tester above to modify the pattern and test with your own data. Common modifications include making it case-insensitive (add 'i' flag), matching globally (add 'g' flag), or adjusting character classes.