nghttp2/doc/nghttpx.1.rst

.. GENERATED by help2rst.py.  DO NOT EDIT DIRECTLY.

.. program:: nghttpx

nghttpx(1)
==========

SYNOPSIS
--------

**nghttpx** [OPTIONS]... [<PRIVATE_KEY> <CERT>]

DESCRIPTION
-----------

A reverse proxy for HTTP/2, HTTP/1 and SPDY.

.. describe:: <PRIVATE_KEY>

    
    Set path  to server's private key.   Required unless :option:`-p`\,
    :option:`--client` or :option:`\--frontend-no-tls` are given.

.. describe:: <CERT>

    Set path  to server's certificate.  Required  unless :option:`-p`\,
    :option:`--client` or  :option:`\--frontend-no-tls` are given.  To  make OCSP
    stapling work, this must be absolute path.


OPTIONS
-------

The options are categorized into several groups.

Connections
~~~~~~~~~~~

.. option:: -b, --backend=(<HOST>,<PORT>|unix:<PATH>)[;<PATTERN>[:...]]

    Set  backend  host  and   port.   The  multiple  backend
    addresses are  accepted by repeating this  option.  UNIX
    domain socket  can be  specified by prefixing  path name
    with "unix:" (e.g., unix:/var/run/backend.sock).

    Optionally, if <PATTERN>s are given, the backend address
    is only used  if request matches the pattern.   If :option:`-s` or
    :option:`-p`  is  used,  <PATTERN>s   are  ignored.   The  pattern
    matching  is closely  designed to  ServeMux in  net/http
    package of Go  programming language.  <PATTERN> consists
    of path, host + path or  just host.  The path must start
    with "*/*".  If  it ends with "*/*", it  matches all request
    path in  its subtree.  To  deal with the request  to the
    directory without  trailing slash,  the path  which ends
    with "*/*" also matches the  request path which only lacks
    trailing '*/*'  (e.g., path  "*/foo/*" matches  request path
    "*/foo*").  If it does not end with "*/*", it performs exact
    match against  the request path.   If host is  given, it
    performs exact match against  the request host.  If host
    alone  is given,  "*/*"  is  appended to  it,  so that  it
    matches  all   request  paths  under  the   host  (e.g.,
    specifying "nghttp2.org" equals to "nghttp2.org/").

    Patterns with  host take  precedence over  patterns with
    just path.   Then, longer patterns take  precedence over
    shorter  ones,  breaking  a  tie by  the  order  of  the
    appearance in the configuration.

    If <PATTERN> is  omitted, "*/*" is used  as pattern, which
    matches  all  request  paths (catch-all  pattern).   The
    catch-all backend must be given.

    When doing  a match, nghttpx made  some normalization to
    pattern, request host and path.  For host part, they are
    converted to lower case.  For path part, percent-encoded
    unreserved characters  defined in RFC 3986  are decoded,
    and any  dot-segments (".."  and ".")   are resolved and
    removed.

    For   example,   :option:`-b`\'127.0.0.1,8080;nghttp2.org/httpbin/'
    matches the  request host "nghttp2.org" and  the request
    path "*/httpbin/get*", but does not match the request host
    "nghttp2.org" and the request path "*/index.html*".

    The  multiple <PATTERN>s  can  be specified,  delimiting
    them            by           ":".             Specifying
    :option:`-b`\'127.0.0.1,8080;nghttp2.org:www.nghttp2.org'  has  the
    same  effect  to specify  :option:`-b`\'127.0.0.1,8080;nghttp2.org'
    and :option:`-b`\'127.0.0.1,8080;www.nghttp2.org'.

    The backend addresses sharing same <PATTERN> are grouped
    together forming  load balancing  group.

    Since ";" and ":" are  used as delimiter, <PATTERN> must
    not  contain these  characters.  Since  ";" has  special
    meaning in shell, the option value must be quoted.


    Default: ``127.0.0.1,80``

.. option:: -f, --frontend=(<HOST>,<PORT>|unix:<PATH>)

    Set  frontend  host and  port.   If  <HOST> is  '\*',  it
    assumes  all addresses  including  both  IPv4 and  IPv6.
    UNIX domain  socket can  be specified by  prefixing path
    name with "unix:" (e.g., unix:/var/run/nghttpx.sock)

    Default: ``*,3000``

.. option:: --backlog=<N>

    Set listen backlog size.

    Default: ``512``

.. option:: --backend-ipv4

    Resolve backend hostname to IPv4 address only.

.. option:: --backend-ipv6

    Resolve backend hostname to IPv6 address only.

.. option:: --backend-http-proxy-uri=<URI>

    Specify      proxy       URI      in       the      form
    http://[<USER>:<PASS>@]<PROXY>:<PORT>.    If   a   proxy
    requires  authentication,  specify  <USER>  and  <PASS>.
    Note that  they must be properly  percent-encoded.  This
    proxy  is used  when the  backend connection  is HTTP/2.
    First,  make  a CONNECT  request  to  the proxy  and  it
    connects  to the  backend  on behalf  of nghttpx.   This
    forms  tunnel.   After  that, nghttpx  performs  SSL/TLS
    handshake with  the downstream through the  tunnel.  The
    timeouts when connecting and  making CONNECT request can
    be     specified    by     :option:`--backend-read-timeout`    and
    :option:`--backend-write-timeout` options.


Performance
~~~~~~~~~~~

.. option:: -n, --workers=<N>

    Set the number of worker threads.

    Default: ``1``

.. option:: --read-rate=<SIZE>

    Set maximum  average read  rate on  frontend connection.
    Setting 0 to this option means read rate is unlimited.

    Default: ``0``

.. option:: --read-burst=<SIZE>

    Set  maximum read  burst  size  on frontend  connection.
    Setting  0  to this  option  means  read burst  size  is
    unlimited.

    Default: ``0``

.. option:: --write-rate=<SIZE>

    Set maximum  average write rate on  frontend connection.
    Setting 0 to this option means write rate is unlimited.

    Default: ``0``

.. option:: --write-burst=<SIZE>

    Set  maximum write  burst size  on frontend  connection.
    Setting  0 to  this  option means  write  burst size  is
    unlimited.

    Default: ``0``

.. option:: --worker-read-rate=<SIZE>

    Set maximum average read rate on frontend connection per
    worker.  Setting  0 to  this option  means read  rate is
    unlimited.  Not implemented yet.

    Default: ``0``

.. option:: --worker-read-burst=<SIZE>

    Set maximum  read burst size on  frontend connection per
    worker.  Setting 0 to this  option means read burst size
    is unlimited.  Not implemented yet.

    Default: ``0``

.. option:: --worker-write-rate=<SIZE>

    Set maximum  average write  rate on  frontend connection
    per worker.  Setting  0 to this option  means write rate
    is unlimited.  Not implemented yet.

    Default: ``0``

.. option:: --worker-write-burst=<SIZE>

    Set maximum write burst  size on frontend connection per
    worker.  Setting 0 to this option means write burst size
    is unlimited.  Not implemented yet.

    Default: ``0``

.. option:: --worker-frontend-connections=<N>

    Set maximum number  of simultaneous connections frontend
    accepts.  Setting 0 means unlimited.

    Default: ``0``

.. option:: --backend-http2-connections-per-worker=<N>

    Set   maximum   number   of  backend   HTTP/2   physical
    connections  per  worker.   If  pattern is  used  in  :option:`-b`
    option, this limit is applied  to each pattern group (in
    other  words, each  pattern group  can have  maximum <N>
    HTTP/2  connections).  The  default  value  is 0,  which
    means  that  the value  is  adjusted  to the  number  of
    backend addresses.  If pattern  is used, this adjustment
    is done for each pattern group.

.. option:: --backend-http1-connections-per-host=<N>

    Set   maximum  number   of  backend   concurrent  HTTP/1
    connections per origin host.   This option is meaningful
    when :option:`-s` option  is used.  The origin  host is determined
    by  authority  portion  of requset  URI  (or  :authority
    header  field  for  HTTP/2).   To limit  the  number  of
    connections   per  frontend   for   default  mode,   use
    :option:`--backend-http1-connections-per-frontend`\.

    Default: ``8``

.. option:: --backend-http1-connections-per-frontend=<N>

    Set   maximum  number   of  backend   concurrent  HTTP/1
    connections per frontend.  This  option is only used for
    default mode.   0 means unlimited.  To  limit the number
    of connections  per host for  HTTP/2 or SPDY  proxy mode
    (-s option), use :option:`--backend-http1-connections-per-host`\.

    Default: ``0``

.. option:: --rlimit-nofile=<N>

    Set maximum number of open files (RLIMIT_NOFILE) to <N>.
    If 0 is given, nghttpx does not set the limit.

    Default: ``0``

.. option:: --backend-request-buffer=<SIZE>

    Set buffer size used to store backend request.

    Default: ``16K``

.. option:: --backend-response-buffer=<SIZE>

    Set buffer size used to store backend response.

    Default: ``16K``


Timeout
~~~~~~~

.. option:: --frontend-http2-read-timeout=<DURATION>

    Specify  read  timeout  for  HTTP/2  and  SPDY  frontend
    connection.

    Default: ``3m``

.. option:: --frontend-read-timeout=<DURATION>

    Specify read timeout for HTTP/1.1 frontend connection.

    Default: ``3m``

.. option:: --frontend-write-timeout=<DURATION>

    Specify write timeout for all frontend connections.

    Default: ``30s``

.. option:: --stream-read-timeout=<DURATION>

    Specify  read timeout  for HTTP/2  and SPDY  streams.  0
    means no timeout.

    Default: ``0``

.. option:: --stream-write-timeout=<DURATION>

    Specify write  timeout for  HTTP/2 and SPDY  streams.  0
    means no timeout.

    Default: ``0``

.. option:: --backend-read-timeout=<DURATION>

    Specify read timeout for backend connection.

    Default: ``3m``

.. option:: --backend-write-timeout=<DURATION>

    Specify write timeout for backend connection.

    Default: ``30s``

.. option:: --backend-keep-alive-timeout=<DURATION>

    Specify keep-alive timeout for backend connection.

    Default: ``2s``

.. option:: --listener-disable-timeout=<DURATION>

    After accepting  connection failed,  connection listener
    is disabled  for a given  amount of time.   Specifying 0
    disables this feature.

    Default: ``0``


SSL/TLS
~~~~~~~

.. option:: --ciphers=<SUITE>

    Set allowed  cipher list.  The  format of the  string is
    described in OpenSSL ciphers(1).

.. option:: -k, --insecure

    Don't  verify   backend  server's  certificate   if  :option:`-p`\,
    :option:`--client`    or    :option:`\--http2-bridge`     are    given    and
    :option:`--backend-no-tls` is not given.

.. option:: --cacert=<PATH>

    Set path to trusted CA  certificate file if :option:`-p`\, :option:`--client`
    or :option:`--http2-bridge` are given  and :option:`\--backend-no-tls` is not
    given.  The file must be  in PEM format.  It can contain
    multiple  certificates.    If  the  linked   OpenSSL  is
    configured to  load system  wide certificates,  they are
    loaded at startup regardless of this option.

.. option:: --private-key-passwd-file=<PATH>

    Path  to file  that contains  password for  the server's
    private key.   If none is  given and the private  key is
    password protected it'll be requested interactively.

.. option:: --subcert=<KEYPATH>:<CERTPATH>

    Specify  additional certificate  and  private key  file.
    nghttpx will  choose certificates based on  the hostname
    indicated  by  client  using TLS  SNI  extension.   This
    option  can  be  used  multiple  times.   To  make  OCSP
    stapling work, <CERTPATH> must be absolute path.

.. option:: --backend-tls-sni-field=<HOST>

    Explicitly  set the  content of  the TLS  SNI extension.
    This will default to the backend HOST name.

.. option:: --dh-param-file=<PATH>

    Path to file that contains  DH parameters in PEM format.
    Without  this   option,  DHE   cipher  suites   are  not
    available.

.. option:: --npn-list=<LIST>

    Comma delimited list of  ALPN protocol identifier sorted
    in the  order of preference.  That  means most desirable
    protocol comes  first.  This  is used  in both  ALPN and
    NPN.  The parameter must be  delimited by a single comma
    only  and any  white spaces  are  treated as  a part  of
    protocol string.

    Default: ``h2,h2-16,h2-14,spdy/3.1,http/1.1``

.. option:: --verify-client

    Require and verify client certificate.

.. option:: --verify-client-cacert=<PATH>

    Path  to file  that contains  CA certificates  to verify
    client certificate.  The file must be in PEM format.  It
    can contain multiple certificates.

.. option:: --client-private-key-file=<PATH>

    Path to  file that contains  client private key  used in
    backend client authentication.

.. option:: --client-cert-file=<PATH>

    Path to  file that  contains client certificate  used in
    backend client authentication.

.. option:: --tls-proto-list=<LIST>

    Comma delimited list of  SSL/TLS protocol to be enabled.
    The following protocols  are available: TLSv1.2, TLSv1.1
    and   TLSv1.0.    The   name   matching   is   done   in
    case-insensitive   manner.    The  parameter   must   be
    delimited by  a single comma  only and any  white spaces
    are treated as a part of protocol string.

    Default: ``TLSv1.2,TLSv1.1``

.. option:: --tls-ticket-key-file=<PATH>

    Path to file that contains  random data to construct TLS
    session ticket  parameters.  If aes-128-cbc is  given in
    :option:`--tls-ticket-key-cipher`\, the  file must  contain exactly
    48    bytes.     If     aes-256-cbc    is    given    in
    :option:`--tls-ticket-key-cipher`\, the  file must  contain exactly
    80  bytes.   This  options  can be  used  repeatedly  to
    specify  multiple ticket  parameters.  If  several files
    are given,  only the  first key is  used to  encrypt TLS
    session  tickets.  Other  keys are  accepted but  server
    will  issue new  session  ticket with  first key.   This
    allows  session  key  rotation.  Please  note  that  key
    rotation  does  not  occur automatically.   User  should
    rearrange  files or  change options  values and  restart
    nghttpx gracefully.   If opening  or reading  given file
    fails, all loaded  keys are discarded and  it is treated
    as if none  of this option is given.  If  this option is
    not given or an error  occurred while opening or reading
    a file,  key is  generated every  1 hour  internally and
    they are  valid for  12 hours.   This is  recommended if
    ticket  key sharing  between  nghttpx  instances is  not
    required.

.. option:: --tls-ticket-key-memcached=<HOST>,<PORT>

    Specify  address of  memcached server  to store  session
    cache.   This  enables  shared TLS  ticket  key  between
    multiple nghttpx  instances.  nghttpx  does not  set TLS
    ticket  key  to  memcached.   The  external  ticket  key
    generator  is required.   nghttpx just  gets TLS  ticket
    keys from  memcached, and  use them,  possibly replacing
    current set of keys.  It is  up to extern TLS ticket key
    generator to  rotate keys frequently.  See  "TLS SESSION
    TICKET RESUMPTION"  section in  manual page to  know the
    data format in memcached entry.

.. option:: --tls-ticket-key-memcached-interval=<DURATION>

    Set interval to get TLS ticket keys from memcached.

    Default: ``10m``

.. option:: --tls-ticket-key-memcached-max-retry=<N>

    Set  maximum   number  of  consecutive   retries  before
    abandoning TLS ticket key  retrieval.  If this number is
    reached,  the  attempt  is considered  as  failure,  and
    "failure" count  is incremented by 1,  which contributed
    to            the            value            controlled
    :option:`--tls-ticket-key-memcached-max-fail` option.

    Default: ``3``

.. option:: --tls-ticket-key-memcached-max-fail=<N>

    Set  maximum   number  of  consecutive   failure  before
    disabling TLS ticket until next scheduled key retrieval.

    Default: ``2``

.. option:: --tls-ticket-key-cipher=<CIPHER>

    Specify cipher  to encrypt TLS session  ticket.  Specify
    either   aes-128-cbc   or  aes-256-cbc.    By   default,
    aes-128-cbc is used.

.. option:: --fetch-ocsp-response-file=<PATH>

    Path to  fetch-ocsp-response script file.  It  should be
    absolute path.

    Default: ``/usr/local/share/nghttp2/fetch-ocsp-response``

.. option:: --ocsp-update-interval=<DURATION>

    Set interval to update OCSP response cache.

    Default: ``4h``

.. option:: --no-ocsp

    Disable OCSP stapling.

.. option:: --tls-session-cache-memcached=<HOST>,<PORT>

    Specify  address of  memcached server  to store  session
    cache.   This  enables   shared  session  cache  between
    multiple nghttpx instances.


HTTP/2 and SPDY
~~~~~~~~~~~~~~~

.. option:: -c, --http2-max-concurrent-streams=<N>

    Set the maximum number of  the concurrent streams in one
    HTTP/2 and SPDY session.

    Default: ``100``

.. option:: --frontend-http2-window-bits=<N>

    Sets the  per-stream initial window size  of HTTP/2 SPDY
    frontend connection.  For HTTP/2,  the size is 2\*\*<N>-1.
    For SPDY, the size is 2\*\*<N>.

    Default: ``16``

.. option:: --frontend-http2-connection-window-bits=<N>

    Sets the  per-connection window size of  HTTP/2 and SPDY
    frontend   connection.    For   HTTP/2,  the   size   is
    2**<N>-1. For SPDY, the size is 2\*\*<N>.

    Default: ``16``

.. option:: --frontend-no-tls

    Disable SSL/TLS on frontend connections.

.. option:: --backend-http2-window-bits=<N>

    Sets  the   initial  window   size  of   HTTP/2  backend
    connection to 2\*\*<N>-1.

    Default: ``16``

.. option:: --backend-http2-connection-window-bits=<N>

    Sets the  per-connection window  size of  HTTP/2 backend
    connection to 2\*\*<N>-1.

    Default: ``16``

.. option:: --backend-no-tls

    Disable SSL/TLS on backend connections.

.. option:: --http2-no-cookie-crumbling

    Don't crumble cookie header field.

.. option:: --padding=<N>

    Add  at most  <N> bytes  to  a HTTP/2  frame payload  as
    padding.  Specify 0 to  disable padding.  This option is
    meant for debugging purpose  and not intended to enhance
    protocol security.

.. option:: --no-server-push

    Disable  HTTP/2  server  push.    Server  push  is  only
    supported  by default  mode and  HTTP/2 frontend.   SPDY
    frontend does not support server push.


Mode
~~~~

.. describe:: (default mode)

    
    Accept  HTTP/2,  SPDY  and HTTP/1.1  over  SSL/TLS.   If
    :option:`--frontend-no-tls` is  used, accept HTTP/2  and HTTP/1.1.
    The  incoming HTTP/1.1  connection  can  be upgraded  to
    HTTP/2  through  HTTP  Upgrade.   The  protocol  to  the
    backend is HTTP/1.1.

.. option:: -s, --http2-proxy

    Like default mode, but enable secure proxy mode.

.. option:: --http2-bridge

    Like default  mode, but communicate with  the backend in
    HTTP/2 over SSL/TLS.  Thus  the incoming all connections
    are converted  to HTTP/2  connection and relayed  to the
    backend.  See :option:`--backend-http-proxy-uri` option if you are
    behind  the proxy  and want  to connect  to the  outside
    HTTP/2 proxy.

.. option:: --client

    Accept  HTTP/2   and  HTTP/1.1  without   SSL/TLS.   The
    incoming HTTP/1.1  connection can be upgraded  to HTTP/2
    connection through  HTTP Upgrade.   The protocol  to the
    backend is HTTP/2.   To use nghttpx as  a forward proxy,
    use :option:`-p` option instead.

.. option:: -p, --client-proxy

    Like :option:`--client`  option, but it also  requires the request
    path from frontend must be an absolute URI, suitable for
    use as a forward proxy.


Logging
~~~~~~~

.. option:: -L, --log-level=<LEVEL>

    Set the severity  level of log output.   <LEVEL> must be
    one of INFO, NOTICE, WARN, ERROR and FATAL.

    Default: ``NOTICE``

.. option:: --accesslog-file=<PATH>

    Set path to write access log.  To reopen file, send USR1
    signal to nghttpx.

.. option:: --accesslog-syslog

    Send  access log  to syslog.   If this  option is  used,
    :option:`--accesslog-file` option is ignored.

.. option:: --accesslog-format=<FORMAT>

    Specify  format  string  for access  log.   The  default
    format is combined format.   The following variables are
    available:

    * $remote_addr: client IP address.
    * $time_local: local time in Common Log format.
    * $time_iso8601: local time in ISO 8601 format.
    * $request: HTTP request line.
    * $status: HTTP response status code.
    * $body_bytes_sent: the  number of bytes sent  to client
      as response body.
    * $http_<VAR>: value of HTTP  request header <VAR> where
      '_' in <VAR> is replaced with '-'.
    * $remote_port: client  port.
    * $server_port: server port.
    * $request_time: request processing time in seconds with
      milliseconds resolution.
    * $pid: PID of the running process.
    * $alpn: ALPN identifier of the protocol which generates
      the response.   For HTTP/1,  ALPN is  always http/1.1,
      regardless of minor version.
    * $ssl_cipher: cipher used for SSL/TLS connection.
    * $ssl_protocol: protocol for SSL/TLS connection.
    * $ssl_session_id: session ID for SSL/TLS connection.
    * $ssl_session_reused:  "r"   if  SSL/TLS   session  was
      reused.  Otherwise, "."

    The  variable  can  be  enclosed  by  "{"  and  "}"  for
    disambiguation (e.g., ${remote_addr}).


    Default: ``$remote_addr - - [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent"``

.. option:: --errorlog-file=<PATH>

    Set path to write error  log.  To reopen file, send USR1
    signal  to nghttpx.   stderr will  be redirected  to the
    error log file unless :option:`--errorlog-syslog` is used.

    Default: ``/dev/stderr``

.. option:: --errorlog-syslog

    Send  error log  to  syslog.  If  this  option is  used,
    :option:`--errorlog-file` option is ignored.

.. option:: --syslog-facility=<FACILITY>

    Set syslog facility to <FACILITY>.

    Default: ``daemon``


HTTP
~~~~

.. option:: --add-x-forwarded-for

    Append  X-Forwarded-For header  field to  the downstream
    request.

.. option:: --strip-incoming-x-forwarded-for

    Strip X-Forwarded-For  header field from  inbound client
    requests.

.. option:: --no-via

    Don't append to  Via header field.  If  Via header field
    is received, it is left unaltered.

.. option:: --no-location-rewrite

    Don't rewrite  location header field  on :option:`--http2-bridge`\,
    :option:`--client`  and  default   mode.   For  :option:`\--http2-proxy`  and
    :option:`--client-proxy` mode,  location header field will  not be
    altered regardless of this option.

.. option:: --host-rewrite

    Rewrite   host   and   :authority   header   fields   on
    :option:`--http2-bridge`\,   :option:`--client`   and  default   mode.    For
    :option:`--http2-proxy`  and  :option:`\--client-proxy` mode,  these  headers
    will not be altered regardless of this option.

.. option:: --altsvc=<PROTOID,PORT[,HOST,[ORIGIN]]>

    Specify   protocol  ID,   port,  host   and  origin   of
    alternative service.  <HOST>  and <ORIGIN> are optional.
    They  are advertised  in  alt-svc header  field only  in
    HTTP/1.1  frontend.  This  option can  be used  multiple
    times   to   specify  multiple   alternative   services.
    Example: :option:`--altsvc`\=h2,443

.. option:: --add-request-header=<HEADER>

    Specify additional header field to add to request header
    set.  This  option just  appends header field  and won't
    replace anything  already set.  This option  can be used
    several  times   to  specify  multiple   header  fields.
    Example: :option:`--add-request-header`\="foo: bar"

.. option:: --add-response-header=<HEADER>

    Specify  additional  header  field to  add  to  response
    header set.   This option just appends  header field and
    won't replace anything already  set.  This option can be
    used several  times to  specify multiple  header fields.
    Example: :option:`--add-response-header`\="foo: bar"

.. option:: --header-field-buffer=<SIZE>

    Set maximum  buffer size for incoming  HTTP header field
    list.   This is  the sum  of  header name  and value  in
    bytes.

    Default: ``64K``

.. option:: --max-header-fields=<N>

    Set maximum number of incoming HTTP header fields, which
    appear in one request or response header field list.

    Default: ``100``


Debug
~~~~~

.. option:: --frontend-http2-dump-request-header=<PATH>

    Dumps request headers received by HTTP/2 frontend to the
    file denoted  in <PATH>.  The  output is done  in HTTP/1
    header field format and each header block is followed by
    an empty line.  This option  is not thread safe and MUST
    NOT be used with option :option:`-n`\<N>, where <N> >= 2.

.. option:: --frontend-http2-dump-response-header=<PATH>

    Dumps response headers sent  from HTTP/2 frontend to the
    file denoted  in <PATH>.  The  output is done  in HTTP/1
    header field format and each header block is followed by
    an empty line.  This option  is not thread safe and MUST
    NOT be used with option :option:`-n`\<N>, where <N> >= 2.

.. option:: -o, --frontend-frame-debug

    Print HTTP/2 frames in  frontend to stderr.  This option
    is  not thread  safe and  MUST NOT  be used  with option
    :option:`-n`\=N, where N >= 2.


Process
~~~~~~~

.. option:: -D, --daemon

    Run in a background.  If :option:`-D` is used, the current working
    directory is changed to '*/*'.

.. option:: --pid-file=<PATH>

    Set path to save PID of this program.

.. option:: --user=<USER>

    Run this program as <USER>.   This option is intended to
    be used to drop root privileges.


Misc
~~~~

.. option:: --conf=<PATH>

    Load configuration from <PATH>.

    Default: ``/etc/nghttpx/nghttpx.conf``

.. option:: --include=<PATH>

    Load additional configurations from <PATH>.  File <PATH>
    is  read  when  configuration  parser  encountered  this
    option.  This option can be used multiple times, or even
    recursively.

.. option:: -v, --version

    Print version and exit.

.. option:: -h, --help

    Print this help and exit.



The <SIZE> argument is an integer and an optional unit (e.g., 10K is
10 * 1024).  Units are K, M and G (powers of 1024).

The <DURATION> argument is an integer and an optional unit (e.g., 1s
is 1 second and 500ms is 500 milliseconds).  Units are h, m, s or ms
(hours, minutes, seconds and milliseconds, respectively).  If a unit
is omitted, a second is used as unit.

FILES
-----

*/etc/nghttpx/nghttpx.conf*
  The default configuration file path nghttpx searches at startup.
  The configuration file path can be changed using :option:`--conf`
  option.

  Those lines which are staring ``#`` are treated as comment.

  The option name in the configuration file is the long command-line
  option name with leading ``--`` stripped (e.g., ``frontend``).  Put
  ``=`` between option name and value.  Don't put extra leading or
  trailing spaces.

  The options which do not take argument in the command-line *take*
  argument in the configuration file.  Specify ``yes`` as an argument
  (e.g., ``http2-proxy=yes``).  If other string is given, it is
  ignored.

  To specify private key and certificate file which are given as
  positional arguments in command-line, use ``private-key-file`` and
  ``certificate-file``.

  :option:`--conf` option cannot be used in the configuration file and
  will be ignored if specified.

SIGNALS
-------

SIGQUIT
  Shutdown gracefully.  First accept pending connections and stop
  accepting connection.  After all connections are handled, nghttpx
  exits.

SIGUSR1
  Reopen log files.

SIGUSR2
  Fork and execute nghttpx.  It will execute the binary in the same
  path with same command-line arguments and environment variables.
  After new process comes up, sending SIGQUIT to the original process
  to perform hot swapping.

SERVER PUSH
-----------

nghttpx supports HTTP/2 server push in default mode.  nghttpx looks
for Link header field (`RFC 5988
<http://tools.ietf.org/html/rfc5988>`_) in response headers from
backend server and extracts URI-reference with parameter
``rel=preload`` (see `preload
<http://w3c.github.io/preload/#interoperability-with-http-link-header>`_)
and pushes those URIs to the frontend client. Here is a sample Link
header field to initiate server push:

.. code-block:: http

  Link: </fonts/font.woff>; rel=preload
  Link: </css/theme.css>; rel=preload

Currently, the following restrictions are applied for server push:

1. URI-reference must not contain authority.  If it exists, it is not
   pushed.  ``/fonts/font.woff`` and ``css/theme.css`` are eligible to
   be pushed.  ``https://example.org/fonts/font.woff`` and
   ``//example.org/css/theme.css`` are not.

2. The associated stream must have method "GET" or "POST".  The
   associated stream's status code must be 200.

These limitations may be loosened in the future release.

UNIX DOMAIN SOCKET
------------------

nghttpx supports UNIX domain socket with a filename for both frontend
and backend connections.

Please note that current nghttpx implementation does not delete a
socket with a filename.  And on start up, if nghttpx detects that the
specified socket already exists in the file system, nghttpx first
deletes it.  However, if SIGUSR2 is used to execute new binary and
both old and new configurations use same filename, new binary does not
delete the socket and continues to use it.

OCSP STAPLING
-------------

OCSP query is done using external Python script
``fetch-ocsp-response``, which has been originally developed in Perl
as part of h2o project (https://github.com/h2o/h2o), and was
translated into Python.

The script file is usually installed under
``$(prefix)/share/nghttp2/`` directory.  The actual path to script can
be customized using :option:`--fetch-ocsp-response-file` option.

TLS SESSION RESUMPTION
----------------------

nghttpx supports TLS session resumption through both session ID and
session ticket.

SESSION ID RESUMPTION
~~~~~~~~~~~~~~~~~~~~~

By default, session ID is shared by all worker threads.

If :option:`--tls-session-cache-memcached` is given, nghttpx will
insert serialized session data to memcached with
``nghttpx:tls-session-cache:`` + lowercased hex string of session ID
as a memcached entry key, with expiry time 12 hours.  Session timeout
is set to 12 hours.

TLS SESSION TICKET RESUMPTION
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

By default, session ticket is shared by all worker threads.  The
automatic key rotation is also enabled by default.  Every an hour, new
encryption key is generated, and previous encryption key becomes
decryption only key.  We set session timeout to 12 hours, and thus we
keep at most 12 keys.

If :option:`--tls-ticket-key-memcached` is given, encryption keys are
retrieved from memcached.  nghttpx just reads keys from memcached; one
has to deploy key generator program to update keys frequently (e.g.,
every 1 hour).  The example key generator tlsticketupdate.go is
available under contrib directory in nghttp2 archive.  The memcached
entry key is ``nghttpx:tls-ticket-key``.  The data format stored in
memcached is the binary format described below::

    +--------------+-------+----------------+
    | VERSION (4)  |LEN (2)|KEY(48 or 80) ...
    +--------------+-------+----------------+
                   ^                        |
		   |                        |
		   +------------------------+
                   (LEN, KEY) pair can be repeated

All numbers in the above figure is bytes.  All integer fields are
network byte order.

First 4 bytes integer VERSION field, which must be 1.  The 2 bytes
integer LEN field gives the length of following KEY field, which
contains key.  If :option:`--tls-ticket-key-cipher`\=aes-128-cbc is
used, LEN must be 48.  If
:option:`--tls-ticket-key-cipher`\=aes-256-cbc is used, LEN must be
80.  LEN and KEY pair can be repeated multiple times to store multiple
keys.  The key appeared first is used as encryption key.  All the
remaining keys are used as decryption only.

If :option:`--tls-ticket-key-file` is given, encryption key is read
from the given file.  In this case, nghttpx does not rotate key
automatically.  To rotate key, one has to restart nghttpx (see
SIGNALS).

SEE ALSO
--------

:manpage:`nghttp(1)`, :manpage:`nghttpd(1)`, :manpage:`h2load(1)`