In the shimmed CNBs used in heroku/builder we have been seeing quite a few transient errors related to buildpacks downloading from S3.
Adding appropriate retries and connection timeouts to all of our buildpack's curl usages should help with these, as well as make builds more reliable in general for users on Heroku, plus also anyone using a shimmed CNB locally with Pack CLI (where the network connection may be even less reliable).
The --retry-connrefused option has been used since otherwise curl doesn't retry cases where the connection was refused. Ideally we would use --retry-all-errors which takes that one step further, however that option was only added in curl 7.71, so is only supported by Heroku-22+.
In the shimmed CNBs used in
heroku/builderwe have been seeing quite a few transient errors related to buildpacks downloading from S3.Adding appropriate retries and connection timeouts to all of our buildpack's curl usages should help with these, as well as make builds more reliable in general for users on Heroku, plus also anyone using a shimmed CNB locally with Pack CLI (where the network connection may be even less reliable).
The
--retry-connrefusedoption has been used since otherwise curl doesn't retry cases where the connection was refused. Ideally we would use--retry-all-errorswhich takes that one step further, however that option was only added in curl 7.71, so is only supported by Heroku-22+.For more on curl options, see: https://curl.se/docs/manpage.html
GUS-W-11283397.