Dash - Reinventing Cryptocurrency
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Wladimir J. van der Laan fefe07003b Merge #14670: http: Fix HTTP server shutdown
28479f926f21f2a91bec5a06671c60e5b0c55532 qa: Test bitcond shutdown (João Barbosa)
8d3f46ec3938e2ba17654fecacd1d2629f9915fd http: Remove timeout to exit event loop (João Barbosa)
e98a9eede2fb48ff33a020acc888cbcd83e24bbf http: Remove unnecessary event_base_loopexit call (João Barbosa)
6b13580f4e3842c11abd9b8bee7255fb2472b6fe http: Unlisten sockets after all workers quit (João Barbosa)
18e968581697078c36a3c3818f8906cf134ccadd http: Send "Connection: close" header if shutdown is requested (João Barbosa)
02e1e4eff6cda0bfc24b455a7c1583394cbff6eb rpc: Add wait argument to stop (João Barbosa)

Pull request description:

  Fixes #11777. Reverts #11006. Replaces #13501.

  With this change the HTTP server will exit gracefully, meaning that all requests will finish processing and sending the response, even if this means to wait more than 2 seconds (current time allowed to exit the event loop).

  Another small change is that connections are accepted even when the server is stopping, but HTTP requests are rejected. This can be improved later, especially if chunked replies are implemented.

  Briefly, before this PR, this is the order or events when a request arrives (RPC `stop`):
   1. `bufferevent_disable(..., EV_READ)`
   2. `StartShutdown()`
   3. `evhttp_del_accept_socket(...)`
   4. `ThreadHTTP` terminates (event loop exits) because there are no active or pending events thanks to 1. and 3.
   5. client doesn't get the response thanks to 4.

  This can be verified by applying
  ```diff
       // Event loop will exit after current HTTP requests have been handled, so
       // this reply will get back to the client.
       StartShutdown();
  +    MilliSleep(2000);
       return "Bitcoin server stopping";
   }
  ```
  and checking the log output:
  ```
      Received a POST request for / from 127.0.0.1:62443
      ThreadRPCServer method=stop user=__cookie__
      Interrupting HTTP server
  **  Exited http event loop
      Interrupting HTTP RPC server
      Interrupting RPC
      tor: Thread interrupt
      Shutdown: In progress...
      torcontrol thread exit
      Stopping HTTP RPC server
      addcon thread exit
      opencon thread exit
      Unregistering HTTP handler for / (exactmatch 1)
      Unregistering HTTP handler for /wallet/ (exactmatch 0)
      Stopping RPC
      RPC stopped.
      Stopping HTTP server
      Waiting for HTTP worker threads to exit
      msghand thread exit
      net thread exit

      ... sleep 2 seconds ...

      Waiting for HTTP event thread to exit
      Stopped HTTP server
  ```

  For this reason point 3. is moved right after all HTTP workers quit. In that moment HTTP replies are queued in the event loop which keeps spinning util all connections are closed. In order to trigger the server side close with keep alive connections (implicit in HTTP/1.1) the header `Connection: close` is sent if shutdown was requested. This can be tested by
  ```
  bitcoind -regtest
  nc localhost 18443
  POST / HTTP/1.1
  Authorization: Basic ...
  Content-Type: application/json
  Content-Length: 44

  {"jsonrpc": "2.0","method":"stop","id":123}
  ```

  Summing up, this PR:
   - removes explicit event loop exit — event loop exits once there are no active or pending events
   - changes the moment the listening sockets are removed — explained above
   - sends header `Connection: close` on active requests when shutdown was requested which is relevant when it's a persistent connection (default in HTTP 1.1) — libevent is aware of this header and closes the connection gracefully
   - removes event loop explicit break after 2 seconds timeout

Tree-SHA512: 4dac1e86abe388697c1e2dedbf31fb36a394cfafe5e64eadbf6ed01d829542785a8c3b91d1ab680d3f03f912d14fc87176428041141441d25dcb6c98a1e069d8
2019-10-14 13:45:09 +02:00
.github Add link to bugcrowd in issue template (#2716) 2019-02-19 13:05:59 +03:00
.tx
build-aux/m4 Merge #10803: Explicitly search for bdb5.3. 2019-07-24 11:59:09 -05:00
ci Fix scripted diff check condition (#3128) 2019-10-01 17:16:26 +03:00
contrib Qt: Remove old themes (#3141) 2019-10-10 14:53:00 +03:00
depends Add OpenSSL termios fix for musl libc (#3099) 2019-09-22 23:47:02 +03:00
doc Update OpenBSD build docs as in bitcoin#11442 2019-09-30 08:33:16 +02:00
docker Automatically build and push docker image to docker.io/dashpay/dashd-develop (#1809) 2018-01-10 12:17:43 +03:00
share Update/modernize macOS plist (#3074) 2019-09-03 22:48:14 +03:00
src Merge #14670: http: Fix HTTP server shutdown 2019-10-14 13:45:09 +02:00
test Merge #14670: http: Fix HTTP server shutdown 2019-10-14 13:45:09 +02:00
.gitattributes
.gitignore bitcoin -> dash 2019-08-24 11:11:25 -05:00
.travis.yml Fix scripted diff check condition (#3128) 2019-10-01 17:16:26 +03:00
autogen.sh Merge #8784: Copyright headers for build scripts 2018-01-12 08:02:45 +01:00
CMakeLists.txt Enable stacktrace support in gitian builds (#3006) 2019-07-02 07:16:11 +03:00
configure.ac Merge #13788: Fix --disable-asm for newer assembly checks/code 2019-10-01 23:20:06 +02:00
CONTRIBUTING.md Merge #11003: Docs: Capitalize bullet points in CONTRIBUTING guide 2019-08-12 09:07:03 -05:00
COPYING Merge #11318: Put back inadvertently removed copyright notices 2019-09-25 10:33:21 +02:00
INSTALL.md Dashify INSTALL.md and build-unix.md 2018-01-12 16:12:54 +01:00
Jenkinsfile Perform Jenkins builds in /dash-src all the time to fix caching issues (#2242) 2018-08-29 13:03:18 +03:00
Jenkinsfile.gitian Let ccache compress the cache by itself instead of compressing ccache.tar (#2456) 2018-11-19 07:31:13 +01:00
libdashconsensus.pc.in
Makefile.am Merge #11530: Add share/rpcuser to dist. source code archive 2019-09-30 08:33:16 +02:00
README.md Merge bitcoin#9956: Reorganise qa directory (#2912) 2019-05-19 23:20:34 +03:00

Dash Core staging tree 0.14.1

master: Build Status develop: Build Status

https://www.dash.org

What is Dash?

Dash is an experimental digital currency that enables anonymous, instant payments to anyone, anywhere in the world. Dash uses peer-to-peer technology to operate with no central authority: managing transactions and issuing money are carried out collectively by the network. Dash Core is the name of the open source software which enables the use of this currency.

For more information, as well as an immediately useable, binary version of the Dash Core software, see https://www.dash.org/get-dash/.

License

Dash Core is released under the terms of the MIT license. See COPYING for more information or see https://opensource.org/licenses/MIT.

Development Process

The master branch is meant to be stable. Development is normally done in separate branches. Tags are created to indicate new official, stable release versions of Dash Core.

The contribution workflow is described in CONTRIBUTING.md.

Testing

Testing and code review is the bottleneck for development; we get more pull requests than we can review and test on short notice. Please be patient and help out by testing other people's pull requests, and remember this is a security-critical project where any mistake might cost people lots of money.

Automated Testing

Developers are strongly encouraged to write unit tests for new code, and to submit new unit tests for old code. Unit tests can be compiled and run (assuming they weren't disabled in configure) with: make check. Further details on running and extending unit tests can be found in /src/test/README.md.

There are also regression and integration tests, written in Python, that are run automatically on the build server. These tests can be run (if the test dependencies are installed) with: test/functional/test_runner.py

The Travis CI system makes sure that every pull request is built for Windows, Linux, and OS X, and that unit/sanity tests are run automatically.

Manual Quality Assurance (QA) Testing

Changes should be tested by somebody other than the developer who wrote the code. This is especially important for large or high-risk changes. It is useful to add a test plan to the pull request description if testing the changes is not straightforward.

Translations

Changes to translations as well as new translations can be submitted to Dash Core's Transifex page.

Translations are periodically pulled from Transifex and merged into the git repository. See the translation process for details on how this works.

Important: We do not accept translation changes as GitHub pull requests because the next pull from Transifex would automatically overwrite them again.

Translators should also follow the forum.