transport-helper: introduce stateless-connect
Introduce the transport-helper capability 'stateless-connect'. This capability indicates that the transport-helper can be requested to run the 'stateless-connect' command which should attempt to make a stateless connection with a remote end. Once established, the connection can be used by the git client to communicate with the remote end natively in a stateless-rpc manner as supported by protocol v2. This means that the client must send everything the server needs in a single request as the client must not assume any state-storing on the part of the server or transport. If a stateless connection cannot be established then the remote-helper will respond in the same manner as the 'connect' command indicating that the client should fallback to using the dumb remote-helper commands. A future patch will implement the 'stateless-connect' capability in our http remote-helper (remote-curl) so that protocol v2 can be used using the http transport. Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Brandon Williams committed
Mar 15, 2018 at 10:31 UTC
edc9caf7e2ecd3d5327e78a3e539eda61a0e4d81
4 files changed
+50
Documentation/gitremote-helpers.txt
+32
@@ -102,6 +102,14 @@ Capabilities for Pushing
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+
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Supported commands: 'connect'.
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+'stateless-connect'::
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+ Experimental; for internal use only.
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+ Can attempt to connect to a remote server for communication
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+ using git's wire-protocol version 2. See the documentation
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+ for the stateless-connect command for more information.
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++
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+Supported commands: 'stateless-connect'.
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+
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'push'::
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Can discover remote refs and push local commits and the
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history leading up to them to new or existing remote refs.
@@ -136,6 +144,14 @@ Capabilities for Fetching
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+
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Supported commands: 'connect'.
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+'stateless-connect'::
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+ Experimental; for internal use only.
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+ Can attempt to connect to a remote server for communication
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+ using git's wire-protocol version 2. See the documentation
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+ for the stateless-connect command for more information.
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++
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+Supported commands: 'stateless-connect'.
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+
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'fetch'::
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Can discover remote refs and transfer objects reachable from
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them to the local object store.
@@ -375,6 +391,22 @@ Supported if the helper has the "export" capability.
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+
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Supported if the helper has the "connect" capability.
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+'stateless-connect' <service>::
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+ Experimental; for internal use only.
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+ Connects to the given remote service for communication using
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+ git's wire-protocol version 2. Valid replies to this command
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+ are empty line (connection established), 'fallback' (no smart
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+ transport support, fall back to dumb transports) and just
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+ exiting with error message printed (can't connect, don't bother
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+ trying to fall back). After line feed terminating the positive
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+ (empty) response, the output of the service starts. Messages
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+ (both request and response) must consist of zero or more
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+ PKT-LINEs, terminating in a flush packet. The client must not
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+ expect the server to store any state in between request-response
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+ pairs. After the connection ends, the remote helper exits.
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++
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+Supported if the helper has the "stateless-connect" capability.
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+
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If a fatal error occurs, the program writes the error message to
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stderr and exits. The caller should expect that a suitable error
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message has been printed if the child closes the connection without
transport-helper.c
+11
@@ -12,6 +12,7 @@
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#include "argv-array.h"
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#include "refs.h"
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#include "transport-internal.h"
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+#include "protocol.h"
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static int debug;
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@@ -26,6 +27,7 @@ struct helper_data {
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option : 1,
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push : 1,
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connect : 1,
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+ stateless_connect : 1,
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signed_tags : 1,
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check_connectivity : 1,
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no_disconnect_req : 1,
@@ -188,6 +190,8 @@ static struct child_process *get_helper(struct transport *transport)
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refspecs[refspec_nr++] = xstrdup(arg);
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} else if (!strcmp(capname, "connect")) {
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data->connect = 1;
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+ } else if (!strcmp(capname, "stateless-connect")) {
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+ data->stateless_connect = 1;
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} else if (!strcmp(capname, "signed-tags")) {
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data->signed_tags = 1;
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} else if (skip_prefix(capname, "export-marks ", &arg)) {
@@ -612,6 +616,13 @@ static int process_connect_service(struct transport *transport,
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if (data->connect) {
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strbuf_addf(&cmdbuf, "connect %s\n", name);
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ret = run_connect(transport, &cmdbuf);
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+ } else if (data->stateless_connect &&
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+ (get_protocol_version_config() == protocol_v2) &&
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+ !strcmp("git-upload-pack", name)) {
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+ strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
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+ ret = run_connect(transport, &cmdbuf);
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+ if (ret)
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+ transport->stateless_rpc = 1;
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}
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strbuf_release(&cmdbuf);
transport.c
+1
@@ -252,6 +252,7 @@ static int fetch_refs_via_pack(struct transport *transport,
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data->options.check_self_contained_and_connected;
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args.cloning = transport->cloning;
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args.update_shallow = data->options.update_shallow;
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+ args.stateless_rpc = transport->stateless_rpc;
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if (!data->got_remote_heads)
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refs_tmp = get_refs_via_connect(transport, 0, NULL);
transport.h
+6
@@ -55,6 +55,12 @@ struct transport {
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*/
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unsigned cloning : 1;
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+ /*
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+ * Indicates that the transport is connected via a half-duplex
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+ * connection and should operate in stateless-rpc mode.
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+ */
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+ unsigned stateless_rpc : 1;
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+
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/*
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* These strings will be passed to the {pre, post}-receive hook,
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* on the remote side, if both sides support the push options capability.