Chainguard Image for wait-for-it

Container image for testing whether a service is listening on an address/port combination.

Chainguard Images are regularly-updated, minimal container images with low-to-zero CVEs.

Download this Image

This image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/wait-for-it:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard registry.

Usage

Simple Example

Test that a service is available!

$ docker run cgr.dev/chainguard/wait-for-it:latest -h google.com -p 80
wait-for-it: waiting 15 seconds for google.com:80
wait-for-it: google.com:80 is available after 0 seconds

Timeout

You can optionally specify a timeout using the -t flag (in seconds):

$  docker run cgr.dev/chainguard/wait-for-it:latest -h fake.doesnotexist -p 80 -t 5
wait-for-it: waiting 5 seconds for fake.doesnotexist:80
wait-for-it: timeout occurred after waiting 5 seconds for fake.doesnotexist:80

Subcommand

You can then run a command after the execution, using the -- syntax.

$ docker run cgr.dev/chainguard/wait-for-it:latest -h fake.doesnotexist -p 80 -t 5 -- echo hello
wait-for-it: waiting 5 seconds for fake.doesnotexist:80
wait-for-it: timeout occurred after waiting 5 seconds for fake.doesnotexist:80
hello

Adding -s will only run the command if wait-for-it succeeds:

$ docker run cgr.dev/chainguard/wait-for-it:latest -h fake.doesnotexist -p 80 -t 5 -s -- echo hello
wait-for-it: waiting 5 seconds for fake.doesnotexist:80
wait-for-it: timeout occurred after waiting 5 seconds for fake.doesnotexist:80
wait-for-it: strict mode, refusing to execute subprocess

Contact Support

If you have a Zendesk account (typically set up for you by your Customer Success Manager) you can reach out to Chainguard's Customer Success team through our Zendesk portal.

What are Chainguard Images?

Chainguard Images are a collection of container images designed for security and minimalism.

Many Chainguard Images are distroless; they contain only an open-source application and its runtime dependencies. These images do not even contain a shell or package manager. Chainguard Images are built with Wolfi, our Linux undistro designed to produce container images that meet the requirements of a secure software supply chain.

The main features of Chainguard Images include:

• Minimal design, with no unnecessary software bloat
• Automated nightly builds to ensure Images are completely up-to-date and contain all available security patches
• High quality build-time SBOMs (software bills of materials) attesting the provenance of all artifacts within the Image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

-dev Variants

As mentioned previously, Chainguard’s distroless Images have no shell or package manager by default. This is great for security, but sometimes you need these things, especially in builder images. For those cases, most (but not all) Chainguard Images come paired with a -dev variant which does include a shell and package manager.

Although the -dev image variants have similar security features as their distroless versions, such as complete SBOMs and signatures, they feature additional software that is typically not necessary in production environments. The general recommendation is to use the -dev variants only to build the application and then copy all application artifacts into a distroless image, which will result in a final container image that has a minimal attack surface and won’t allow package installations or logins.

That being said, it’s worth noting that -dev variants of Chainguard Images are completely fine to run in production environments. After all, the -dev variants are still more secure than many popular container images based on fully-featured operating systems such as Debian and Ubuntu since they carry less software, follow a more frequent patch cadence, and offer attestations for what they include.

Learn More

To better understand how to work with Chainguard Images, we encourage you to visit Chainguard Academy, our documentation and education platform.