comparison tests/test-http-api-httpv2.t @ 37054:40206e227412

wireproto: define and implement protocol for issuing requests

The existing HTTP and SSH wire protocols suffer from a host of flaws
and shortcomings. I've been wanting to rewrite the protocol for a while
now. Supporting partial clone - which will require new wire protocol
commands and capabilities - and other advanced server functionality
will be much easier if we start from a clean slate and don't have
to be constrained by limitations of the existing wire protocol.

This commit starts to introduce a new data exchange format for
use over the wire protocol.

The new protocol is built on top of "frames," which are atomic
units of metadata + data. Frames will make it easier to implement
proxies and other mechanisms that want to inspect data without
having to maintain state. The existing frame metadata is very
minimal and it will evolve heavily. (We will eventually support
things like concurrent requests, out-of-order responses,
compression, side-channels for status updates, etc. Some of
these will require additions to the frame header.)

Another benefit of frames is that all reads are of a fixed size.
A reader works by consuming a frame header, extracting the payload
length, then reading that many bytes. No lookahead, buffering, or
memory reallocations are needed.

The new protocol attempts to be transport agnostic. I want all that's
required to use the new protocol to be a pair of unidirectional,
half-duplex pipes. (Yes, we will eventually make use of full-duplex
pipes, but that's for another commit.) Notably, when the SSH
transport switches to this new protocol, stderr will be unused.
This is by design: the lack of stderr on HTTP harms protocol
behavior there. By shoehorning everything into a pair of pipes,
we can have more consistent behavior across transports.

We currently only define the client side parts of the new protocol,
specifically the bits for requesting that a command run. This keeps
the new code and feature small and somewhat easy to review.

We add support to `hg debugwireproto` for writing frames into
HTTP request bodies. Our tests that issue commands to the new
HTTP endpoint have been updated to transmit frames. The server
bits haven't been touched to consume the frames yet. This will
occur in the next commit...

Astute readers may notice that the command name is transmitted in
both the HTTP request URL and the command request frame. This is
partially a kludge from me initially implementing the frame-based
protocol for SSH first. But it is also a feature: I intend to
eventually support issuing multiple commands per HTTP request. This
will allow us to replace the abomination that is the "batch" wire
protocol command with a protocol-level mechanism for performing
multi-dispatch. Because I want the frame-based protocol to be
as similar as possible across transports, I'd rather we (redundantly)
include the command name in the frame than differ behavior between
transports that have out-of-band routing information (like HTTP)
readily available.

Differential Revision: https://phab.mercurial-scm.org/D2851

37053:37d7a1d18b97

  $ HTTPV2=exp-http-v2-0001
  $ MEDIATYPE=application/mercurial-tbd

  $ send() {
  >   hg --verbose debugwireproto --peer raw http://$LOCALIP:$HGPORT/
  > }

  s> makefile('rb', None)
  s>     HTTP/1.1 406 Not Acceptable\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 72\r\n
  s>     \r\n
  s>     client MUST specify Accept header with value: application/mercurial-tbd\n

Bad Accept header results in 406

  $ send << EOF
  > httprequest POST api/$HTTPV2/ro/customreadonly

  s> makefile('rb', None)
  s>     HTTP/1.1 406 Not Acceptable\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 72\r\n
  s>     \r\n
  s>     client MUST specify Accept header with value: application/mercurial-tbd\n

Bad Content-Type header results in 415

  $ send << EOF
  > httprequest POST api/$HTTPV2/ro/customreadonly

  >     content-type: badmedia
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     accept: application/mercurial-tbd\r\n
  s>     content-type: badmedia\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 415 Unsupported Media Type\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 75\r\n
  s>     \r\n
  s>     client MUST send Content-Type header with value: application/mercurial-tbd\n

Request to read-only command works out of the box

  $ send << EOF
  > httprequest POST api/$HTTPV2/ro/customreadonly
  >     accept: $MEDIATYPE
  >     content-type: $MEDIATYPE
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     accept: application/mercurial-tbd\r\n
  s>     content-type: application/mercurial-tbd\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 200 OK\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n

  $ send << EOF
  > httprequest POST api/$HTTPV2/rw/customreadonly
  >     user-agent: test
  >     accept: $MEDIATYPE
  >     content-type: $MEDIATYPE
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/rw/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     accept: application/mercurial-tbd\r\n
  s>     content-type: application/mercurial-tbd\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 200 OK\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n

  >     accept: $MEDIATYPE
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/rw/badcommand HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     accept: application/mercurial-tbd\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 404 Not Found\r\n

37054:40206e227412

  $ HTTPV2=exp-http-v2-0001
  $ MEDIATYPE=application/mercurial-exp-framing-0001

  $ send() {
  >   hg --verbose debugwireproto --peer raw http://$LOCALIP:$HGPORT/
  > }

  s> makefile('rb', None)
  s>     HTTP/1.1 406 Not Acceptable\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 85\r\n
  s>     \r\n
  s>     client MUST specify Accept header with value: application/mercurial-exp-framing-0001\n

Bad Accept header results in 406

  $ send << EOF
  > httprequest POST api/$HTTPV2/ro/customreadonly

  s> makefile('rb', None)
  s>     HTTP/1.1 406 Not Acceptable\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 85\r\n
  s>     \r\n
  s>     client MUST specify Accept header with value: application/mercurial-exp-framing-0001\n

Bad Content-Type header results in 415

  $ send << EOF
  > httprequest POST api/$HTTPV2/ro/customreadonly

  >     content-type: badmedia
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     accept: application/mercurial-exp-framing-0001\r\n
  s>     content-type: badmedia\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 415 Unsupported Media Type\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 88\r\n
  s>     \r\n
  s>     client MUST send Content-Type header with value: application/mercurial-exp-framing-0001\n

Request to read-only command works out of the box

  $ send << EOF
  > httprequest POST api/$HTTPV2/ro/customreadonly
  >     accept: $MEDIATYPE
  >     content-type: $MEDIATYPE
  >     user-agent: test
  >     frame command-name eos customreadonly
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     accept: application/mercurial-exp-framing-0001\r\n
  s>     content-type: application/mercurial-exp-framing-0001\r\n
  s>     user-agent: test\r\n
  s>     content-length: 18\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s>     \x0e\x00\x00\x11customreadonly
  s> makefile('rb', None)
  s>     HTTP/1.1 200 OK\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n

  $ send << EOF
  > httprequest POST api/$HTTPV2/rw/customreadonly
  >     user-agent: test
  >     accept: $MEDIATYPE
  >     content-type: $MEDIATYPE
  >     frame command-name eos customreadonly
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/rw/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     accept: application/mercurial-exp-framing-0001\r\n
  s>     content-type: application/mercurial-exp-framing-0001\r\n
  s>     user-agent: test\r\n
  s>     content-length: 18\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s>     \x0e\x00\x00\x11customreadonly
  s> makefile('rb', None)
  s>     HTTP/1.1 200 OK\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n

  >     accept: $MEDIATYPE
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/rw/badcommand HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     accept: application/mercurial-exp-framing-0001\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 404 Not Found\r\n