libpcap VS skopeo

As long as your custom service used the rpcap protocol I'd expect it to be possible. You may find this GitHub page informative, since it includes some rpcap source code and one of the main Wireshark developers appears to be a contributor there.

mitmproxy can be used to find the HTTP request with the needed data in addition browser dev tools. At some point, I'll explore tcpdump and wireshark to reverse engineer websites for web scraping and share the learnings with you.

(Of course, this consideration should be appropriately downweighted by YAGNI, as threading memory management through prototype or internal utility code can by itself easily force it into very non-prototype amounts of effort.)

[1] https://github.com/the-tcpdump-group/libpcap/blob/2180b6e56a...

I am working with libpcap, a library that parses packets captured from tcpdump, which I have cIncluded from Zig.

Nmap and Wireshark, tcpdump tools can be used to scan networks and packets.

Also definitely start looking at tcpdump and wireshark. These are invaluable tools for the non-network engineer that is perhaps a sysadmin or analyst to use for network troubleshooting.

For future reference, libpcap is a library that Wireshark and many other network analysis tools use to record network traffic. It has its own file format that it can use to save the recorded network traffic to disk.

A lot is covered here and here, sar might be useful, getfacl and tcpdump and probably hundred more tools I am not even aware of. The easiest to learn those is to have a problem and identify and solve it with those tools, but to do that you need to know roughly what those tools can do.

For example, gopacket uses libpcap by default for capturing the traffic. Libpcap doesn't support network namespaces and we can't ask it to listen to traffic on a different namespace. However, we can change the network namespace of the calling thread and then start libpcap to see the traffic on a different namespace.

I decided to go searching for an alternative means to pull a docker image. In my search I discovered Skopeo, an alternative method to download Docker images that proved to be surprisingly effective. It not only downloaded the image faster, it also allowed me to save my image in a tar file, which means you can pull an image on one system and share that image to another system, loading it easily to docker instance on that system. This can be very beneficial if you have multiple systems and don't want to download an image multiple times.

But I'd suggest looking into if it's solved by other tools already, like regclient/regclient and their regsync features or something like containers/skopeo.

Have a use case where we have a CLI (built with cobra) for our dev teams which can execute common tasks. One of those tasks we want to implement is to copy docker images from the internet to our internal registry. A tool such as skopeo can do this and much more. Instead of essentially re-writing the functionality directly into our CLI we'd like to embed it. This would also negate the need for the dev teams to manage multiple CLI tools.

Self hoisting here, I put this together to make it easier to generate single (extra) layer docker images without needing a docker agent, capabilities, chroot, etc: https://github.com/andrewbaxter/dinker

Caveat: it doesn't work on Fly.io. They seem to be having some issue with OCI manifests: https://github.com/containers/skopeo/issues/1881 . They're also having issues with new docker versions pushing from CI: https://community.fly.io/t/deploying-to-fly-via-github-actio... ... the timing of this post seems weird.

FWIW the article says

> create a Docker image, also known as an OCI image

I don't think this is quite right. From my investigation, Docker and OCI images are basically content addressed trees, starting with a root manifest that points to other files and their hashes (root -> images -> layers -> layer configs + files). The OCI manifests and configs are separate to Docker manifests and configs and basically Docker will support both side by side.

skopeo is another tool worth looking into. we've started deploying amd and arm nodes into our k8s clusters, and this tool was incredibly easy to build around for getting multi-arch images into our container registry.

I would use skopeo, the tool is quite handy for working with remote images. https://github.com/containers/skopeo

Using distroless images not only reduces the size of the container image it also reduces the surface attack. The need for container image signing is because even with the distroless images there is a chance of facing some security threats such as receiving a malicious image. We can use cosign or skopeo for container signing and verifying. You can read more about securing containers with Cosign and Distroless Images in this blog.

Look at using tools like skopeo or crane

You could try some commandline tool like skopeo to fetch the image tags regularly and do some shell magic to notify you on any change you want

This is what Podman, an open-source daemonless and rootless container engine, was developed with in mind. Podman runs using the runC container runtime process, directly on the Linux kernel, and launches containers and pods as child processes. In addition, it was developed for the Docker developer, with most commands and syntax seamlessly mirroring Docker's. Buildah, an image builder, and Skopeo, the image utility tool, are both complimentary to Podman as well, and extend the range of operations able to be performed.