Added markdown-link-check to azure-pipelines.yml

[Jimmys20]

This PR adds markdown-link-check to azure-pipelines.yml. It is already added to .vsts-ci.yml as part of #1970.

Seems to be working now. I wonder if the script should be modified to allow it to continue scanning after a problematic link is found and maybe show warning instead of throwing. Sometimes links might be temporary down like in this case, hackernoon.com is down and the script stopped execution but it would be nice if it continued scanning.

Also https://www.digikey.com/ got Status: 403 Forbidden which is interesting. Never had that happen while testing locally.

Microsoft Reviewers: Open in CodeFlow

[joperezr]

Hello @Jimmys20, thank you so much for the contribution. We discussed this PR during triage and decided that it was probably better if we had this step to run on its own job in order for it to be easier for us to diagnose the reason for a failing build. I hope you don't mind, but I took the liberty to push the appropriate changes into your PR in order to adjust for that.

[joperezr]

@Jimmys20 would you mind also checking why we are now getting another failure? I'd rather add more patterns to skip but keep the check green before we merge.

[Jimmys20]

Looks like it's not very consistent with the external URLs. I committed a change (added verbose logging) which made the task rerun and now it stopped in a different URL. It is strange because all links are reported either as alive or ignored when I run the command on my computer. I don't get any broken links. Can you reproduce the azure pipelines behavior on your computer?

[krwq]

@Jimmys20 for links which you are 100% sure they are not going down anytime soon (Ali Express or digi key) you can just add them to the ignore list permanently (pointless even to make web-request).

Also another option you can setup retryCount and some delay: https://github.com/tcort/markdown-link-check#config-file-format

[Jimmys20]

Execute markdown-link-check job completed successfully!

[pgrawehr]

@krwq aliexpress isn't going down anytime soon, but the deep links within it (e.g. to a product) surely can.

[krwq]

@pgrawehr I know but the specific link shared was a root path :)

[krwq]

Thanks @Jimmys20!