413 lines
15 KiB
ReStructuredText
413 lines
15 KiB
ReStructuredText
.. program:: nghttpx
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nghttpx - HTTP/2 proxy - HOW-TO
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===============================
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:doc:`nghttpx.1` is a proxy translating protocols between HTTP/2 and
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other protocols (e.g., HTTP/1, SPDY). It operates in several modes
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and each mode may require additional programs to work with. This
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article describes each operation mode and explains the intended
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use-cases. It also covers some useful options later.
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Default mode
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------------
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If nghttpx is invoked without :option:`--http2-proxy`, it operates in
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default mode. In this mode, it works as reverse proxy (gateway) for
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both HTTP/2 and HTTP/1 clients to backend servers. This is also known
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as "HTTP/2 router". If nghttpx is linked with spdylay library and
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frontend connection is SSL/TLS, the frontend also supports SPDY
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protocol.
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By default, frontend connection is encrypted using SSL/TLS. So
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server's private key and certificate must be supplied to the command
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line (or through configuration file). In this case, the frontend
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protocol selection will be done via ALPN or NPN.
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To turn off encryption on frontend connection, use ``no-tls`` keyword
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in :option:`--frontend` option. In this case, SPDY protocol is not
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available even if spdylay library is liked to nghttpx. HTTP/2 and
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HTTP/1 are available on the frontend, and an HTTP/1 connection can be
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upgraded to HTTP/2 using HTTP Upgrade. Starting HTTP/2 connection by
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sending HTTP/2 connection preface is also supported.
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nghttpx can listen on multiple frontend addresses. This is achieved
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by using multiple :option:`--frontend` options. For each frontend
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address, TLS can be enabled or disabled.
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By default, backend connections are not encrypted. To enable TLS
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encryption on backend connections, use ``tls`` keyword in
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:option:`--backend` option. Using patterns and ``proto`` keyword in
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:option:`--backend` option, backend application protocol can be
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specified per host/request path pattern. It means that you can use
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both HTTP/2 and HTTP/1 in backend connections at the same time. Note
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that default backend protocol is HTTP/1.1. To use HTTP/2 in backend,
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you have to specify ``h2`` in ``proto`` keyword in :option:`--backend`
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explicitly.
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The backend is supposed to be Web server. For example, to make
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nghttpx listen to encrypted HTTP/2 requests at port 8443, and a
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backend Web server is configured to listen to HTTP request at port
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8080 in the same host, run nghttpx command-line like this:
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.. code-block:: text
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$ nghttpx -f0.0.0.0,8443 -b127.0.0.1,8080 /path/to/server.key /path/to/server.crt
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Then HTTP/2 enabled client can access to the nghttpx in HTTP/2. For
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example, you can send GET request to the server using nghttp:
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.. code-block:: text
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$ nghttp -nv https://localhost:8443/
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HTTP/2 proxy mode
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-----------------
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If nghttpx is invoked with :option:`--http2-proxy` (or its shorthand
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:option:`-s`) option, it operates in HTTP/2 proxy mode. The supported
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protocols in frontend and backend connections are the same in `default
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mode`_. The difference is that this mode acts like forward proxy and
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assumes the backend is HTTP proxy server (e.g., Squid, Apache Traffic
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Server). HTTP/1 request must include absolute URI in request line.
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By default, frontend connection is encrypted. So this mode is also
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called secure proxy. If nghttpx is linked with spdylay, it supports
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SPDY protocols and it works as so called SPDY proxy.
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To turn off encryption on frontend connection, use ``no-tls`` keyword
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in :option:`--frontend` option.
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The backend must be HTTP proxy server. nghttpx supports multiple
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backend server addresses. It translates incoming requests to HTTP
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request to backend server. The backend server performs real proxy
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work for each request, for example, dispatching requests to the origin
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server and caching contents.
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The backend connection is not encrypted by default. To enable
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encryption, use ``tls`` keyword in :option:`--backend` option. The
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default backend protocol is HTTP/1.1. To use HTTP/2 in backend
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connection, use :option:`--backend` option, and specify ``h2`` in
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``proto`` keyword explicitly.
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For example, to make nghttpx listen to encrypted HTTP/2 requests at
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port 8443, and a backend HTTP proxy server is configured to listen to
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HTTP/1 request at port 8080 in the same host, run nghttpx command-line
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like this:
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.. code-block:: text
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$ nghttpx -s -f'*,8443' -b127.0.0.1,8080 /path/to/server.key /path/to/server.crt
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At the time of this writing, Firefox 41 and Chromium v46 can use
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nghttpx as HTTP/2 proxy.
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To make Firefox or Chromium use nghttpx as HTTP/2 or SPDY proxy, user
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has to create proxy.pac script file like this:
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.. code-block:: javascript
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function FindProxyForURL(url, host) {
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return "HTTPS SERVERADDR:PORT";
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}
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``SERVERADDR`` and ``PORT`` is the hostname/address and port of the
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machine nghttpx is running. Please note that both Firefox and
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Chromium require valid certificate for secure proxy.
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For Firefox, open Preference window and select Advanced then click
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Network tab. Clicking Connection Settings button will show the
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dialog. Select "Automatic proxy configuration URL" and enter the path
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to proxy.pac file, something like this:
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.. code-block:: text
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file:///path/to/proxy.pac
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For Chromium, use following command-line:
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.. code-block:: text
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$ google-chrome --proxy-pac-url=file:///path/to/proxy.pac --use-npn
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As HTTP/1 proxy server, Squid may work as out-of-box. Traffic server
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requires to be configured as forward proxy. Here is the minimum
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configuration items to edit:
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.. code-block:: text
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CONFIG proxy.config.reverse_proxy.enabled INT 0
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CONFIG proxy.config.url_remap.remap_required INT 0
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Consult Traffic server `documentation
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<http://trafficserver.readthedocs.org/en/latest/admin-guide/configuration/transparent-forward-proxying.en.html>`_
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to know how to configure traffic server as forward proxy and its
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security implications.
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ALPN support
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------------
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ALPN support requires OpenSSL >= 1.0.2.
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Disable frontend SSL/TLS
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------------------------
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The frontend connections are encrypted with SSL/TLS by default. To
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turn off SSL/TLS, use ``no-tls`` keyword in :option:`--frontend`
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option. If this option is used, the private key and certificate are
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not required to run nghttpx.
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Enable backend SSL/TLS
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----------------------
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The backend connections are not encrypted by default. To enable
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SSL/TLS encryption, use ``tls`` keyword in :option:`--backend` option.
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Enable SSL/TLS on memcached connection
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--------------------------------------
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By default, memcached connection is not encrypted. To enable
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encryption, use ``tls`` keyword in
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:option:`--tls-ticket-key-memcached` for TLS ticket key, and
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:option:`--tls-session-cache-memcached` for TLS session cache.
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Specifying additional server certificates
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-----------------------------------------
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nghttpx accepts additional server private key and certificate pairs
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using :option:`--subcert` option. It can be used multiple times.
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Specifying additional CA certificate
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------------------------------------
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By default, nghttpx tries to read CA certificate from system. But
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depending on the system you use, this may fail or is not supported.
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To specify CA certificate manually, use :option:`--cacert` option.
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The specified file must be PEM format and can contain multiple
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certificates.
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By default, nghttpx validates server's certificate. If you want to
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turn off this validation, knowing this is really insecure and what you
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are doing, you can use :option:`--insecure` option to disable
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certificate validation.
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Read/write rate limit
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---------------------
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nghttpx supports transfer rate limiting on frontend connections. You
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can do rate limit per frontend connection for reading and writing
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individually.
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To perform rate limit for reading, use :option:`--read-rate` and
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:option:`--read-burst` options. For writing, use
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:option:`--write-rate` and :option:`--write-burst`.
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Please note that rate limit is performed on top of TCP and nothing to
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do with HTTP/2 flow control.
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Rewriting location header field
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-------------------------------
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nghttpx automatically rewrites location response header field if the
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following all conditions satisfy:
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* URI in location header field is not absolute URI or is not https URI.
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* URI in location header field includes non empty host component.
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* host (without port) in URI in location header field must match the
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host appearing in :authority or host header field.
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When rewrite happens, URI scheme and port are replaced with the ones
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used in frontend, and host is replaced with which appears in
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:authority or host request header field. :authority header field has
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precedence. If the above conditions are not met with the host value
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in :authority header field, rewrite is retried with the value in host
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header field.
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Hot swapping
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------------
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nghttpx supports hot swapping using signals. The hot swapping in
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nghttpx is multi step process. First send USR2 signal to nghttpx
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process. It will do fork and execute new executable, using same
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command-line arguments and environment variables. At this point, both
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current and new processes can accept requests. To gracefully shutdown
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current process, send QUIT signal to current nghttpx process. When
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all existing frontend connections are done, the current process will
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exit. At this point, only new nghttpx process exists and serves
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incoming requests.
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If you want to just reload configuration file without executing new
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binary, send SIGHUP to nghttpx master process.
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Re-opening log files
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--------------------
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When rotating log files, it is desirable to re-open log files after
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log rotation daemon renamed existing log files. To tell nghttpx to
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re-open log files, send USR1 signal to nghttpx process. It will
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re-open files specified by :option:`--accesslog-file` and
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:option:`--errorlog-file` options.
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Multiple frontend addresses
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---------------------------
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nghttpx can listen on multiple frontend addresses. To specify them,
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just use :option:`--frontend` (or its shorthand :option:`-f`) option
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repeatedly. TLS can be enabled or disabled per frontend address
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basis. For example, to listen on port 443 with TLS enabled, and on
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port 80 without TLS:
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.. code-block:: text
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frontend=*,443
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frontend=*,80;no-tls
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Multiple backend addresses
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--------------------------
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nghttpx supports multiple backend addresses. To specify them, just
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use :option:`--backend` (or its shorthand :option:`-b`) option
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repeatedly. For example, to use ``192.168.0.10:8080`` and
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``192.168.0.11:8080``, use command-line like this:
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``-b192.168.0.10,8080 -b192.168.0.11,8080``. In configuration file,
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this looks like:
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.. code-block:: text
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backend=192.168.0.10,8080
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backend=192.168.0.11,8008
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nghttpx can route request to different backend according to request
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host and path. For example, to route request destined to host
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``doc.example.com`` to backend server ``docserv:3000``, you can write
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like so:
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.. code-block:: text
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backend=docserv,3000;doc.example.com/
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When you write this option in command-line, you should enclose
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argument with single or double quotes, since the character ``;`` has a
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special meaning in shell.
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To route, request to request path whose prefix is ``/foo`` to backend
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server ``[::1]:8080``, you can write like so:
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.. code-block:: text
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backend=::1,8080;/foo
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Of course, you can specify both host and request path at the same
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time:
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.. code-block:: text
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backend=192.168.0.10,8080;example.com/foo
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We can use ``*`` in the left most position of host to achieve wildcard
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suffix match. If ``*`` is the left most character, then the remaining
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string should match the request host suffix. ``*`` must match at
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least one character. For example, ``*.example.com`` matches
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``www.example.com`` and ``dev.example.com``, and does not match
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``example.com`` and ``nghttp2.org``. The exact match (without ``*``)
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always takes precedence over wildcard match.
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One important thing you have to remember is that we have to specify
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default routing pattern for so called "catch all" pattern. To write
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"catch all" pattern, just specify backend server address, without
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pattern.
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Usually, host is the value of ``Host`` header field. In HTTP/2, the
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value of ``:authority`` pseudo header field is used.
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When you write multiple backend addresses sharing the same routing
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pattern, they are used as load balancing. For example, to use 2
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servers ``serv1:3000`` and ``serv2:3000`` for request host
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``example.com`` and path ``/myservice``, you can write like so:
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.. code-block:: text
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backend=serv1,3000;example.com/myservice
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backend=serv2,3000;example.com/myservice
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You can also specify backend application protocol in
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:option:`--backend` option using ``proto`` keyword after pattern.
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Utilizing this allows ngttpx to route certain request to HTTP/2, other
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requests to HTTP/1. For example, to route requests to ``/ws/`` in
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backend HTTP/1.1 connection, and use backend HTTP/2 for other
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requests, do this:
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.. code-block:: text
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backend=serv1,3000;/;proto=h2
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backend=serv1,3000;/ws/;proto=http/1.1
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Note that the backends share the same pattern must have the same
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backend protocol. The default backend protocol is HTTP/1.1.
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TLS can be enabed per pattern basis:
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.. code-block:: text
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backend=serv1,8443;/;proto=h2;tls
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backend=serv2,8080;/ws/;proto=http/1.1
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In the above case, connection to serv1 will be encrypted by TLS. On
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the other hand, connection to serv2 will not be encrypted by TLS.
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Migration from nghttpx v1.8.0 or earlier
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----------------------------------------
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As of nghttpx 1.9.0, ``--frontend-no-tls`` and ``--backend-no-tls``
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have been removed.
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To disable encryption on frontend connection, use ``no-tls`` keyword
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in :option:`--frontend` potion:
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.. code-block:: text
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frontend=*,3000;no-tls
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The TLS encryption is now disabled on backend connection in all modes
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by default. To enable encryption on backend connection, use ``tls``
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keyword in :option:`--backend` option:
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.. code-block:: text
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backend=127.0.0.1,8080;tls
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As of nghttpx 1.9.0, ``--http2-bridge``, ``--client`` and
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``--client-proxy`` options have been removed. These functionality can
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be used using combinations of options.
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Use following option instead of ``--http2-bridge``:
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.. code-block:: text
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backend=<ADDR>,<PORT>;;proto=h2;tls
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Use following options instead of ``--client``:
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.. code-block:: text
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frontend=<ADDR>,<PORT>;no-tls
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backend=<ADDR>,<PORT>;;proto=h2;tls
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Use following options instead of ``--client-proxy``:
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.. code-block:: text
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http2-proxy=yes
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frontend=<ADDR>,<PORT>;no-tls
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backend=<ADDR>,<PORT>;;proto=h2;tls
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We also removed ``--backend-http2-connections-per-worker`` option. It
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was present because previously the number of backend h2 connection was
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statically configured, and defaulted to 1. Now the number of backend
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h2 connection is increased on demand. We know the maximum number of
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concurrent streams per connection. When we push as many request as
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the maximum concurrency to the one connection, we create another new
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connection so that we can distribute load and avoid delay the request
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processing. This is done automatically without any configuration.
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