d460267613
When a server S knows that some objects from a repository are available from a promisor remote X, S might want to suggest to a client C cloning or fetching the repo from S that C may use X directly instead of S for these objects. Note that this could happen both in the case S itself doesn't have the objects and borrows them from X, and in the case S has the objects but knows that X is better connected to the world (e.g., it is in a $LARGEINTERNETCOMPANY datacenter with petabit/s backbone connections) than S. Implementation of the latter case, which would require S to omit in its response the objects available on X, is left for future improvement though. Then C might or might not, want to get the objects from X. If S and C can agree on C using X directly, S can then omit objects that can be obtained from X when answering C's request. To allow S and C to agree and let each other know about C using X or not, let's introduce a new "promisor-remote" capability in the protocol v2, as well as a few new configuration variables: - "promisor.advertise" on the server side, and: - "promisor.acceptFromServer" on the client side. By default, or if "promisor.advertise" is set to 'false', a server S will not advertise the "promisor-remote" capability. If S doesn't advertise the "promisor-remote" capability, then a client C replying to S shouldn't advertise the "promisor-remote" capability either. If "promisor.advertise" is set to 'true', S will advertise its promisor remotes with a string like: promisor-remote=<pr-info>[;<pr-info>]... where each <pr-info> element contains information about a single promisor remote in the form: name=<pr-name>[,url=<pr-url>] where <pr-name> is the urlencoded name of a promisor remote and <pr-url> is the urlencoded URL of the promisor remote named <pr-name>. For now, the URL is passed in addition to the name. In the future, it might be possible to pass other information like a filter-spec that the client may use when cloning from S, or a token that the client may use when retrieving objects from X. It is C's responsibility to arrange how it can reach X though, so pieces of information that are usually outside Git's concern, like proxy configuration, must not be distributed over this protocol. It might also be possible in the future for "promisor.advertise" to have other values. For example a value like "onlyName" could prevent S from advertising URLs, which could help in case C should use a different URL for X than the URL S is using. (The URL S is using might be an internal one on the server side for example.) By default or if "promisor.acceptFromServer" is set to "None", C will not accept to use the promisor remotes that might have been advertised by S. In this case, C will not advertise any "promisor-remote" capability in its reply to S. If "promisor.acceptFromServer" is set to "All" and S advertised some promisor remotes, then on the contrary, C will accept to use all the promisor remotes that S advertised and C will reply with a string like: promisor-remote=<pr-name>[;<pr-name>]... where the <pr-name> elements are the urlencoded names of all the promisor remotes S advertised. In a following commit, other values for "promisor.acceptFromServer" will be implemented, so that C will be able to decide the promisor remotes it accepts depending on the name and URL it received from S. So even if that name and URL information is not used much right now, it will be needed soon. Helped-by: Taylor Blau <me@ttaylorr.com> Helped-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
71 lines
2.3 KiB
C
71 lines
2.3 KiB
C
#ifndef PROMISOR_REMOTE_H
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#define PROMISOR_REMOTE_H
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#include "repository.h"
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struct object_id;
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/*
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* Promisor remote linked list
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*
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* Information in its fields come from remote.XXX config entries or
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* from extensions.partialclone, except for 'accepted' which comes
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* from protocol v2 capabilities exchange.
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*/
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struct promisor_remote {
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struct promisor_remote *next;
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char *partial_clone_filter;
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unsigned int accepted : 1;
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const char name[FLEX_ARRAY];
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};
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void repo_promisor_remote_reinit(struct repository *r);
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void promisor_remote_clear(struct promisor_remote_config *config);
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struct promisor_remote *repo_promisor_remote_find(struct repository *r, const char *remote_name);
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int repo_has_promisor_remote(struct repository *r);
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/*
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* Fetches all requested objects from all promisor remotes, trying them one at
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* a time until all objects are fetched.
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*
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* If oid_nr is 0, this function returns immediately.
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*/
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void promisor_remote_get_direct(struct repository *repo,
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const struct object_id *oids,
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int oid_nr);
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/*
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* Prepare a "promisor-remote" advertisement by a server.
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* Check the value of "promisor.advertise" and maybe the configured
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* promisor remotes, if any, to prepare information to send in an
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* advertisement.
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* Return value is NULL if no promisor remote advertisement should be
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* made. Otherwise it contains the names and urls of the advertised
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* promisor remotes separated by ';'. See gitprotocol-v2(5).
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*/
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char *promisor_remote_info(struct repository *repo);
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/*
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* Prepare a reply to a "promisor-remote" advertisement from a server.
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* Check the value of "promisor.acceptfromserver" and maybe the
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* configured promisor remotes, if any, to prepare the reply.
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* Return value is NULL if no promisor remote from the server
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* is accepted. Otherwise it contains the names of the accepted promisor
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* remotes separated by ';'. See gitprotocol-v2(5).
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*/
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char *promisor_remote_reply(const char *info);
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/*
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* Set the 'accepted' flag for some promisor remotes. Useful on the
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* server side when some promisor remotes have been accepted by the
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* client.
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*/
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void mark_promisor_remotes_as_accepted(struct repository *repo, const char *remotes);
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/*
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* Has any promisor remote been accepted by the client?
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*/
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int repo_has_accepted_promisor_remote(struct repository *r);
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#endif /* PROMISOR_REMOTE_H */
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