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[PATCH 3/4] {fetch,upload}-pack: sideband v2 fetch response

From
JTJonathan Tan <jonathantanmy@google.com>
Date
Jan 11, 2019, 22:18 UTC
Message-ID
<673b928b4158b0aecca843302483b48da5ed8d35.1547244620.git.jonathantanmy@google.com>
In-Reply-To
<cover.1547244620.git.jonathantanmy@google.com>

Currently, a response to a fetch request has sideband support only while the packfile is being sent, meaning that the server cannot send notices until the start of the packfile.

Extend sideband support in protocol v2 fetch responses to the whole response. upload-pack will advertise it if the uploadpack.allowsidebandall configuration variable is set, and fetch-pack will automatically request it if advertised.

If the sideband is to be used throughout the whole response, upload-pack will use it to send errors instead of prefixing a PKT-LINE payload with "ERR ".

This will be tested in a subsequent patch.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
 Documentation/technical/protocol-v2.txt | 10 +++++
 fetch-pack.c                            | 12 +++++-
 pkt-line.c                              | 51 +++++++++++++++++++------
 pkt-line.h                              |  4 ++
 sideband.c                              |  7 +++-
 sideband.h                              |  2 +-
 upload-pack.c                           | 16 ++++++++
 7 files changed, 87 insertions(+), 15 deletions(-)
diff --git a/Documentation/technical/protocol-v2.txt b/Documentation/technical/protocol-v2.txt
index 09e4e0273f..1b0633f59f 100644
--- a/Documentation/technical/protocol-v2.txt
+++ b/Documentation/technical/protocol-v2.txt
@@ -307,6 +307,16 @@ the 'wanted-refs' section in the server's response as explained below.
 	particular ref, where <ref> is the full name of a ref on the
 	server.
 
+If the 'sideband-all' feature is advertised, the following argument can be
+included in the client's request:
+
+    sideband-all
+	Instruct the server to send the whole response multiplexed, not just
+	the packfile section. All non-flush and non-delim PKT-LINE in the
+	response (not only in the packfile section) will then start with a byte
+	indicating its sideband (1, 2, or 3), and the server may send "0005\1"
+	(a PKT-LINE of sideband 1 with no payload) as a keepalive packet.
+
 The response of `fetch` is broken into a number of sections separated by
 delimiter packets (0001), with each section beginning with its section
 header.
diff --git a/fetch-pack.c b/fetch-pack.c
index 3f9626dbf7..b89199891d 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1125,7 +1125,8 @@ static int add_haves(struct fetch_negotiator *negotiator,
 static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
 			      const struct fetch_pack_args *args,
 			      const struct ref *wants, struct oidset *common,
-			      int *haves_to_send, int *in_vain)
+			      int *haves_to_send, int *in_vain,
+			      int sideband_all)
 {
 	int ret = 0;
 	struct strbuf req_buf = STRBUF_INIT;
@@ -1151,6 +1152,8 @@ static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
 		packet_buf_write(&req_buf, "include-tag");
 	if (prefer_ofs_delta)
 		packet_buf_write(&req_buf, "ofs-delta");
+	if (sideband_all)
+		packet_buf_write(&req_buf, "sideband-all");
 
 	/* Add shallow-info and deepen request */
 	if (server_supports_feature("fetch", "shallow", 0))
@@ -1359,6 +1362,10 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 	packet_reader_init(&reader, fd[0], NULL, 0,
 			   PACKET_READ_CHOMP_NEWLINE |
 			   PACKET_READ_DIE_ON_ERR_PACKET);
+	if (server_supports_feature("fetch", "sideband-all", 0)) {
+		reader.use_sideband = 1;
+		reader.me = "fetch-pack";
+	}
 
 	while (state != FETCH_DONE) {
 		switch (state) {
@@ -1392,7 +1399,8 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 		case FETCH_SEND_REQUEST:
 			if (send_fetch_request(&negotiator, fd[1], args, ref,
 					       &common,
-					       &haves_to_send, &in_vain))
+					       &haves_to_send, &in_vain,
+					       reader.use_sideband))
 				state = FETCH_GET_PACK;
 			else
 				state = FETCH_PROCESS_ACKS;
diff --git a/pkt-line.c b/pkt-line.c
index ebdc6c2530..71b17e6b93 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -447,7 +447,7 @@ int recv_sideband(const char *me, int in_stream, int out)
 
 	while (1) {
 		len = packet_read(in_stream, NULL, NULL, buf, LARGE_PACKET_MAX, 0);
-		retval = diagnose_sideband(me, buf, len);
+		retval = diagnose_sideband(me, buf, len, 0);
 		switch (retval) {
 			case SIDEBAND_PRIMARY:
 				write_or_die(out, buf + 1, len - 1);
@@ -483,16 +483,42 @@ enum packet_read_status packet_reader_read(struct packet_reader *reader)
 		return reader->status;
 	}
 
-	reader->status = packet_read_with_status(reader->fd,
-						 &reader->src_buffer,
-						 &reader->src_len,
-						 reader->buffer,
-						 reader->buffer_size,
-						 &reader->pktlen,
-						 reader->options);
+	while (1) {
+		int retval;
+		reader->status = packet_read_with_status(reader->fd,
+							 &reader->src_buffer,
+							 &reader->src_len,
+							 reader->buffer,
+							 reader->buffer_size,
+							 &reader->pktlen,
+							 reader->options);
+		if (!reader->use_sideband)
+			break;
+		retval = diagnose_sideband(reader->me, reader->buffer,
+					   reader->pktlen, 1);
+		switch (retval) {
+			case SIDEBAND_PROTOCOL_ERROR:
+			case SIDEBAND_REMOTE_ERROR:
+				BUG("should have died in diagnose_sideband");
+			case SIDEBAND_FLUSH:
+				goto nonprogress;
+			case SIDEBAND_PRIMARY:
+				if (reader->pktlen != 1)
+					goto nonprogress;
+				/*
+				 * Since pktlen is 1, this is a keepalive
+				 * packet. Wait for the next one.
+				 */
+				break;
+			default: /* SIDEBAND_PROGRESS */
+				;
+		}
+	}
 
+nonprogress:
 	if (reader->status == PACKET_READ_NORMAL)
-		reader->line = reader->buffer;
+		reader->line = reader->use_sideband ?
+			reader->buffer + 1 : reader->buffer;
 	else
 		reader->line = NULL;
 
@@ -514,6 +540,7 @@ enum packet_read_status packet_reader_peek(struct packet_reader *reader)
 void packet_writer_init(struct packet_writer *writer, int dest_fd)
 {
 	writer->dest_fd = dest_fd;
+	writer->use_sideband = 0;
 }
 
 void packet_writer_write(struct packet_writer *writer, const char *fmt, ...)
@@ -521,7 +548,8 @@ void packet_writer_write(struct packet_writer *writer, const char *fmt, ...)
 	va_list args;
 
 	va_start(args, fmt);
-	packet_write_fmt_1(writer->dest_fd, 0, "", fmt, args);
+	packet_write_fmt_1(writer->dest_fd, 0,
+			   writer->use_sideband ? "\1" : "", fmt, args);
 	va_end(args);
 }
 
@@ -530,7 +558,8 @@ void packet_writer_error(struct packet_writer *writer, const char *fmt, ...)
 	va_list args;
 
 	va_start(args, fmt);
-	packet_write_fmt_1(writer->dest_fd, 0, "ERR ", fmt, args);
+	packet_write_fmt_1(writer->dest_fd, 0,
+			   writer->use_sideband ? "\3" : "ERR ", fmt, args);
 	va_end(args);
 }
 
diff --git a/pkt-line.h b/pkt-line.h
index a8e92a4b63..ad9a4a2cd7 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -162,6 +162,9 @@ struct packet_reader {
 
 	/* indicates if a line has been peeked */
 	int line_peeked;
+
+	unsigned use_sideband : 1;
+	const char *me;
 };
 
 /*
@@ -201,6 +204,7 @@ extern char packet_buffer[LARGE_PACKET_MAX];
 
 struct packet_writer {
 	int dest_fd;
+	unsigned use_sideband : 1;
 };
 
 void packet_writer_init(struct packet_writer *writer, int dest_fd);
diff --git a/sideband.c b/sideband.c
index 842a92e975..cbeab380ae 100644
--- a/sideband.c
+++ b/sideband.c
@@ -113,7 +113,7 @@ static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
 #define ANSI_SUFFIX "\033[K"
 #define DUMB_SUFFIX "        "
 
-int diagnose_sideband(const char *me, char *buf, int len)
+int diagnose_sideband(const char *me, char *buf, int len, int die_on_error)
 {
 	static const char *suffix;
 	struct strbuf outbuf = STRBUF_INIT;
@@ -144,6 +144,9 @@ int diagnose_sideband(const char *me, char *buf, int len)
 	len--;
 	switch (band) {
 	case 3:
+		if (die_on_error)
+			die("remote error: %s", buf + 1);
+
 		strbuf_addf(&outbuf, "%s%s", outbuf.len ? "\n" : "",
 			    DISPLAY_PREFIX);
 		maybe_colorize_sideband(&outbuf, buf + 1, len);
@@ -196,6 +199,8 @@ int diagnose_sideband(const char *me, char *buf, int len)
 	}
 
 cleanup:
+	if (die_on_error && retval == SIDEBAND_PROTOCOL_ERROR)
+		die("%s", outbuf.buf);
 	if (outbuf.len) {
 		strbuf_addch(&outbuf, '\n');
 		xwrite(2, outbuf.buf, outbuf.len);
diff --git a/sideband.h b/sideband.h
index a56cd86287..3786670694 100644
--- a/sideband.h
+++ b/sideband.h
@@ -16,7 +16,7 @@
  * prints a message (or the formatted contents of the notice in the case of
  * SIDEBAND_PROGRESS) to stderr.
  */
-int diagnose_sideband(const char *me, char *buf, int len);
+int diagnose_sideband(const char *me, char *buf, int len, int die_on_error);
 
 void send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max);
 
diff --git a/upload-pack.c b/upload-pack.c
index 60a26bbbfd..765b7695d2 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -71,6 +71,8 @@ static int allow_filter;
 static int allow_ref_in_want;
 static struct list_objects_filter_options filter_options;
 
+static int allow_sideband_all;
+
 static void reset_timeout(void)
 {
 	alarm(timeout);
@@ -1046,6 +1048,8 @@ static int upload_pack_config(const char *var, const char *value, void *unused)
 		allow_filter = git_config_bool(var, value);
 	} else if (!strcmp("uploadpack.allowrefinwant", var)) {
 		allow_ref_in_want = git_config_bool(var, value);
+	} else if (!strcmp("uploadpack.allowsidebandall", var)) {
+		allow_sideband_all = git_config_bool(var, value);
 	}
 
 	if (current_config_scope() != CONFIG_SCOPE_REPO) {
@@ -1284,6 +1288,11 @@ static void process_args(struct packet_reader *request,
 			continue;
 		}
 
+		if (allow_sideband_all && !strcmp(arg, "sideband-all")) {
+			data->writer.use_sideband = 1;
+			continue;
+		}
+
 		/* ignore unknown lines maybe? */
 		die("unexpected line: '%s'", arg);
 	}
@@ -1496,6 +1505,7 @@ int upload_pack_advertise(struct repository *r,
 	if (value) {
 		int allow_filter_value;
 		int allow_ref_in_want;
+		int allow_sideband_all_value;
 
 		strbuf_addstr(value, "shallow");
 
@@ -1510,6 +1520,12 @@ int upload_pack_advertise(struct repository *r,
 					 &allow_ref_in_want) &&
 		    allow_ref_in_want)
 			strbuf_addstr(value, " ref-in-want");
+
+		if (!repo_config_get_bool(the_repository,
+					 "uploadpack.allowsidebandall",
+					 &allow_sideband_all_value) &&
+		    allow_sideband_all_value)
+			strbuf_addstr(value, " sideband-all");
 	}
 
 	return 1;

-- 
2.19.0.271.gfe8321ec05.dirty
Previous: Jonathan TanNext: Junio C Hamano
Message 10 of 41 in “Sideband the whole fetch v2 response”
  1. 0/4 Sideband the whole fetch v2 responseJonathan Tan, Jan 11, 2019
  2. 1/4 pkt-line: introduce struct packet_writerJonathan Tan, Jan 11, 2019
  3. Junio C HamanoJan 14, 2019
  4. Jonathan TanJan 15, 2019
  5. 2/4 sideband: reverse its dependency on pkt-lineJonathan Tan, Jan 11, 2019
  6. Junio C HamanoJan 14, 2019
  7. Junio C HamanoJan 14, 2019
  8. Jonathan TanJan 15, 2019
  9. Jonathan TanJan 15, 2019
  10. 3/4 {fetch,upload}-pack: sideband v2 fetch responseJonathan Tan, Jan 11, 2019
  11. Junio C HamanoJan 14, 2019
  12. Jonathan TanJan 15, 2019
  13. 4/4 tests: define GIT_TEST_SIDEBAND_ALLJonathan Tan, Jan 11, 2019
  14. 5/4 Documentation: order protocol v2 sectionsJonathan Tan, Jan 11, 2019
  15. 6/4 Documentation: add Packfile URIs design docJonathan Tan, Jan 11, 2019
  16. 7/4 upload-pack: refactor reading of pack-objects outJonathan Tan, Jan 11, 2019
  17. 8/4 upload-pack: send part of packfile response as uriJonathan Tan, Jan 11, 2019
  18. 0/4 Sideband the whole fetch v2 responseJonathan Tan, Jan 15, 2019
  19. 1/4 pkt-line: introduce struct packet_writerJonathan Tan, Jan 15, 2019
  20. 2/4 sideband: reverse its dependency on pkt-lineJonathan Tan, Jan 15, 2019
  21. SZEDER GáborJan 16, 2019
  22. Jonathan TanJan 16, 2019
  23. SZEDER GáborJan 16, 2019
  24. 3/4 {fetch,upload}-pack: sideband v2 fetch responseJonathan Tan, Jan 15, 2019
  25. 4/4 tests: define GIT_TEST_SIDEBAND_ALLJonathan Tan, Jan 15, 2019
  26. Junio C HamanoJan 15, 2019
  27. Junio C HamanoJan 15, 2019
  28. Jonathan TanJan 15, 2019
  29. Junio C HamanoJan 15, 2019
  30. Jonathan TanJan 15, 2019
  31. Junio C HamanoJan 15, 2019
  32. Jonathan TanJan 16, 2019
  33. Junio C HamanoJan 16, 2019
  34. 0/4 Sideband the whole fetch v2 responseJonathan Tan, Jan 16, 2019
  35. 1/4 pkt-line: introduce struct packet_writerJonathan Tan, Jan 16, 2019
  36. 2/4 sideband: reverse its dependency on pkt-lineJonathan Tan, Jan 16, 2019
  37. 3/4 {fetch,upload}-pack: sideband v2 fetch responseJonathan Tan, Jan 16, 2019
  38. 4/4 tests: define GIT_TEST_SIDEBAND_ALLJonathan Tan, Jan 16, 2019
  39. Jonathan NiederJan 29, 2019
  40. Jeff KingFeb 13, 2019
  41. Junio C HamanoJan 17, 2019

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