Am 28.07.2018 um 00:32 schrieb Junio C Hamano: > Josh Steadmon <stead...@google.com> writes: > >> # Supporting HTTP remotes in "git archive" >> >> We would like to allow remote archiving from HTTP servers. There are a >> few possible implementations to be discussed: >> >> ## Shallow clone to temporary repo >> >> This approach builds on existing endpoints. Clients will connect to the >> remote server's git-upload-pack service and fetch a shallow clone of the >> requested commit into a temporary local repo. The write_archive() >> function is then called on the local clone to write out the requested >> archive.
A prototype would require just a few lines of shell script, I guess.. A downside that was only stated implicitly: This method needs temporary disk space for the clone, while the existing archive modes only ever write out the resulting file. I guess the required space is in the same order as the compressed archive. This shouldn't be a problem if we assume the user would eventually want to extract its contents, right? >> ## Summary >> >> Personally, I lean towards the first approach. It could give us an >> opportunity to remove server-side complexity; there is no reason that >> the shallow-clone approach must be restricted to the HTTP transport, and >> we could re-implement other transports using this method. Additionally, >> it would allow clients to pull archives from remotes that would not >> otherwise support it. > > I consider the first one (i.e. make a shallow clone and tar it up > locally) a hack that does *not* belong to "git archive --remote" > command, especially when it is only done to "http remotes". The > only reason HTTP remotes are special is because there is no ready > "http-backend" equivalent that passes the "git archive" traffic over > smart-http transport, unlike the one that exists for "git > upload-pack". > > It however still _is_ attractive to drive such a hack from "git > archive" at the UI level, as the end users do not care how ugly the > hack is ;-) As you mentioned, the approach would work for any > transport that allows one-commit shallow clone, so it might become > more palatable if it is designed as a different _mode_ of operation > of "git archive" that is orthogonal to the underlying transport, > i.e. > > $ git archive --remote=<repo> --shallow-clone-then-local-archive-hack > master > > or > > $ git config archive.<repo>.useShallowCloneThenLocalArchiveHack true > $ git archive --remote=<repo> master Archive-via-clone would also work with full clones (if shallow ones are not available), but that would be wasteful and a bit cruel, of course. Anyway, I think we should find a better (shorter) name for that option; that could turn out to be the hardest part. :) > It might turn out that it may work better than the native "git > archive" access against servers that offer both shallow clone > and native archive access. I doubt a single-commit shallow clone > would benefit from reusing of premade deltas and compressed bases > streamed straight out of packfiles from the server side that much, > but you'd never know until you measure ;-) It could benefit from GIT_ALTERNATE_OBJECT_DIRECTORIES, but I guess typical users of git archive --remote won't have any good ones lying around. René
