Module ngx_http_scgi_module

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Module ngx_http_scgi_module

Example Configuration
Directives
scgi_allow_upstream
scgi_bind
scgi_bind_dynamic
scgi_buffer_size
scgi_buffering
scgi_buffers
scgi_busy_buffers_size
scgi_cache
scgi_cache_background_update
scgi_cache_bypass
scgi_cache_key
scgi_cache_lock
scgi_cache_lock_age
scgi_cache_lock_timeout
scgi_cache_max_range_offset
scgi_cache_methods
scgi_cache_min_uses
scgi_cache_path
scgi_cache_purge
scgi_cache_revalidate
scgi_cache_use_stale
scgi_cache_valid
scgi_connect_timeout
scgi_force_ranges
scgi_hide_header
scgi_ignore_client_abort
scgi_ignore_headers
scgi_intercept_errors
scgi_limit_rate
scgi_max_temp_file_size
scgi_next_upstream
scgi_next_upstream_timeout
scgi_next_upstream_tries
scgi_no_cache
scgi_param
scgi_pass
scgi_pass_header
scgi_pass_request_body
scgi_pass_request_headers
scgi_read_timeout
scgi_request_buffering
scgi_request_dynamic
scgi_send_timeout
scgi_socket_keepalive
scgi_store
scgi_store_access
scgi_temp_file_write_size
scgi_temp_path

The ngx_http_scgi_module module allows passing
requests to an SCGI server.

Example Configuration

location / {
include scgi_params;
scgi_pass localhost:9000;
}

Directives

Syntax:

scgi_allow_upstream string ...;

Default:

—

Context:

http, server, location

This directive appeared in version 1.29.3.

Defines conditions under which access to an SCGI server
is allowed or denied.
If all string parameters are not empty
and not equal to “0” then the access is allowed.
The conditions are evaluated each time
before a connection to an SCGI server is established.
Parameter values can contain variables:

geo $upstream_last_addr $allow {
volatile;
10.10.0.0/24 1;
}

server {
listen 127.0.0.1:8080;

location / {
scgi_pass localhost:9000;
scgi_allow_upstream $allow;
...
}
}

This directive is available as part of our
commercial subscription.

Syntax:

scgi_bind
address
[transparent] |
off;

Default:

—

Context:

http, server, location

Makes outgoing connections to an SCGI server originate
from the specified local IP address with an optional port (1.11.2).
Parameter value can contain variables (1.3.12).
The special value off (1.3.12) cancels the effect
of the scgi_bind directive
inherited from the previous configuration level, which allows the
system to auto-assign the local IP address and port.

The transparent parameter (1.11.0) allows
outgoing connections to an SCGI server originate
from a non-local IP address,
for example, from a real IP address of a client:

scgi_bind $remote_addr transparent;

In order for this parameter to work,
it is usually necessary to run nginx worker processes with the
superuser privileges.
On Linux it is not required (1.13.8) as if
the transparent parameter is specified, worker processes
inherit the CAP_NET_RAW capability from the master process.
It is also necessary to configure kernel routing table
to intercept network traffic from the SCGI server.

Syntax:

scgi_bind_dynamic on | off;

Default:

scgi_bind_dynamic off;

Context:

http, server, location

This directive appeared in version 1.29.3.

When enabled, makes the bind operation
at each connection attempt.

This directive is available as part of our
commercial subscription.

Syntax:

scgi_buffer_size size;

Default:

scgi_buffer_size 4k|8k;

Context:

http, server, location

Sets the size of the buffer used for reading the first part
of the response received from the SCGI server.
This part usually contains a small response header;
if it exceeds the buffer size, the response is considered
invalid.
By default, the buffer size is equal to one memory page.
This is either 4K or 8K, depending on a platform.
It can be made smaller, however.

Syntax:

scgi_buffering on | off;

Default:

scgi_buffering on;

Context:

http, server, location

Enables or disables buffering of responses from the SCGI server.

When buffering is enabled, nginx receives a response from the SCGI server
as soon as possible, saving it into the buffers set by the
scgi_buffer_size and scgi_buffers directives.
If the whole response does not fit into memory, a part of it can be saved
to a temporary file on the disk.
Writing to temporary files is controlled by the
scgi_max_temp_file_size and
scgi_temp_file_write_size directives.

When buffering is disabled, the response is passed to a client synchronously,
immediately as it is received.
nginx will not try to read the whole response from the SCGI server.
The maximum size of the data that nginx can receive from the server
at a time is set by the scgi_buffer_size directive.

Buffering can also be enabled or disabled by passing
“yes” or “no” in the
“X-Accel-Buffering” response header field.
This capability can be disabled using the
scgi_ignore_headers directive.

Syntax:

scgi_buffers number size;

Default:

scgi_buffers 8 4k|8k;

Context:

http, server, location

Sets the number and size of the
buffers used for reading a response from the SCGI server,
for a single connection.
By default, the buffer size is equal to one memory page.
This is either 4K or 8K, depending on a platform.

Syntax:

scgi_busy_buffers_size size;

Default:

scgi_busy_buffers_size 8k|16k;

Context:

http, server, location

When buffering of responses from the SCGI
server is enabled, limits the total size of buffers that
can be busy sending a response to the client while the response is not
yet fully read.
In the meantime, the rest of the buffers can be used for reading the response
and, if needed, buffering part of the response to a temporary file.
By default, size is limited by the size of two buffers set by the
scgi_buffer_size and scgi_buffers directives.

Syntax:

scgi_cache zone | off;

Default:

scgi_cache off;

Context:

http, server, location

Defines a shared memory zone used for caching.
The same zone can be used in several places.
Parameter value can contain variables (1.7.9).
The off parameter disables caching inherited
from the previous configuration level.

Syntax:

scgi_cache_background_update on | off;

Default:

scgi_cache_background_update off;

Context:

http, server, location

This directive appeared in version 1.11.10.

Allows starting a background subrequest
to update an expired cache item,
while a stale cached response is returned to the client.
Note that it is necessary to
allow
the usage of a stale cached response when it is being updated.

Syntax:

scgi_cache_bypass string ...;

Default:

—

Context:

http, server, location

Defines conditions under which the response will not be taken from a cache.
If at least one value of the string parameters is not empty and is not
equal to “0” then the response will not be taken from the cache:

scgi_cache_bypass $cookie_nocache $arg_nocache$arg_comment;
scgi_cache_bypass $http_pragma $http_authorization;

Can be used along with the scgi_no_cache directive.

Syntax:

scgi_cache_key string;

Default:

—

Context:

http, server, location

Defines a key for caching, for example

scgi_cache_key localhost:9000$request_uri;

Syntax:

scgi_cache_lock on | off;

Default:

scgi_cache_lock off;

Context:

http, server, location

This directive appeared in version 1.1.12.

When enabled, only one request at a time will be allowed to populate
a new cache element identified according to the scgi_cache_key
directive by passing a request to an SCGI server.
Other requests of the same cache element will either wait
for a response to appear in the cache or the cache lock for
this element to be released, up to the time set by the
scgi_cache_lock_timeout directive.

Syntax:

scgi_cache_lock_age time;

Default:

scgi_cache_lock_age 5s;

Context:

http, server, location

This directive appeared in version 1.7.8.

If the last request passed to the SCGI server
for populating a new cache element
has not completed for the specified time,
one more request may be passed to the SCGI server.

Syntax:

scgi_cache_lock_timeout time;

Default:

scgi_cache_lock_timeout 5s;

Context:

http, server, location

This directive appeared in version 1.1.12.

Sets a timeout for scgi_cache_lock.
When the time expires,
the request will be passed to the SCGI server,
however, the response will not be cached.

Before 1.7.8, the response could be cached.

Syntax:

scgi_cache_max_range_offset number;

Default:

—

Context:

http, server, location

This directive appeared in version 1.11.6.

Sets an offset in bytes for byte-range requests.
If the range is beyond the offset,
the range request will be passed to the SCGI server
and the response will not be cached.

Syntax:

scgi_cache_methods
GET |
HEAD |
POST
...;

Default:

scgi_cache_methods GET HEAD;

Context:

http, server, location

If the client request method is listed in this directive then
the response will be cached.
“GET” and “HEAD” methods are always
added to the list, though it is recommended to specify them explicitly.
See also the scgi_no_cache directive.

Syntax:

scgi_cache_min_uses number;

Default:

scgi_cache_min_uses 1;

Context:

http, server, location

Sets the number of requests after which the response
will be cached.

Syntax:

scgi_cache_path
path
[levels=levels]
[use_temp_path=on|off]
keys_zone=name:size
[inactive=time]
[max_size=size]
[min_free=size]
[manager_files=number]
[manager_sleep=time]
[manager_threshold=time]
[loader_files=number]
[loader_sleep=time]
[loader_threshold=time]
[purger=on|off]
[purger_files=number]
[purger_sleep=time]
[purger_threshold=time];

Default:

—

Context:

http

Sets the path and other parameters of a cache.
Cache data are stored in files.
The file name in a cache is a result of
applying the MD5 function to the
cache key.
The levels parameter defines hierarchy levels of a cache:
from 1 to 3, each level accepts values 1 or 2.
For example, in the following configuration

scgi_cache_path /data/nginx/cache levels=1:2 keys_zone=one:10m;

file names in a cache will look like this:

/data/nginx/cache/c/29/b7f54b2df7773722d382f4809d65029c

A cached response is first written to a temporary file,
and then the file is renamed.
Starting from version 0.8.9, temporary files and the cache can be put on
different file systems.
However, be aware that in this case a file is copied
across two file systems instead of the cheap renaming operation.
It is thus recommended that for any given location both cache and a directory
holding temporary files
are put on the same file system.
A directory for temporary files is set based on
the use_temp_path parameter (1.7.10).
If this parameter is omitted or set to the value on,
the directory set by the scgi_temp_path directive
for the given location will be used.
If the value is set to off,
temporary files will be put directly in the cache directory.

In addition, all active keys and information about data are stored
in a shared memory zone, whose name and size
are configured by the keys_zone parameter.
One megabyte zone can store about 8 thousand keys.

As part of
commercial subscription,
the shared memory zone also stores extended
cache information,
thus, it is required to specify a larger zone size for the same number of keys.
For example,
one megabyte zone can store about 4 thousand keys.

Cached data that are not accessed during the time specified by the
inactive parameter get removed from the cache
regardless of their freshness.
By default, inactive is set to 10 minutes.

The special “cache manager” process monitors the maximum cache size set
by the max_size parameter,
and the minimum amount of free space set
by the min_free (1.19.1) parameter
on the file system with cache.
When the size is exceeded or there is not enough free space,
it removes the least recently used data.
The data is removed in iterations configured by
manager_files,
manager_threshold, and
manager_sleep parameters (1.11.5).
During one iteration no more than manager_files items
are deleted (by default, 100).
The duration of one iteration is limited by the
manager_threshold parameter (by default, 200 milliseconds).
Between iterations, a pause configured by the manager_sleep
parameter (by default, 50 milliseconds) is made.

A minute after the start the special “cache loader” process is activated.
It loads information about previously cached data stored on file system
into a cache zone.
The loading is also done in iterations.
During one iteration no more than loader_files items
are loaded (by default, 100).
Besides, the duration of one iteration is limited by the
loader_threshold parameter (by default, 200 milliseconds).
Between iterations, a pause configured by the loader_sleep
parameter (by default, 50 milliseconds) is made.

Additionally,
the following parameters are available as part of our
commercial subscription:

purger=on|off

Instructs whether cache entries that match a
wildcard key
will be removed from the disk by the cache purger (1.7.12).
Setting the parameter to on
(default is off)
will activate the “cache purger” process that
permanently iterates through all cache entries
and deletes the entries that match the wildcard key.

purger_files=number

Sets the number of items that will be scanned during one iteration (1.7.12).
By default, purger_files is set to 10.

purger_threshold=number

Sets the duration of one iteration (1.7.12).
By default, purger_threshold is set to 50 milliseconds.

purger_sleep=number

Sets a pause between iterations (1.7.12).
By default, purger_sleep is set to 50 milliseconds.

In versions 1.7.3, 1.7.7, and 1.11.10 cache header format has been changed.
Previously cached responses will be considered invalid
after upgrading to a newer nginx version.

Syntax:

scgi_cache_purge string ...;

Default:

—

Context:

http, server, location

This directive appeared in version 1.5.7.

Defines conditions under which the request will be considered a cache
purge request.
If at least one value of the string parameters is not empty and is not equal
to “0” then the cache entry with a corresponding
cache key is removed.
The result of successful operation is indicated by returning
the 204 (No Content) response.

If the cache key of a purge request ends
with an asterisk (“*”), all cache entries matching the
wildcard key will be removed from the cache.
However, these entries will remain on the disk until they are deleted
for either inactivity,
or processed by the cache purger (1.7.12),
or a client attempts to access them.

Example configuration:

scgi_cache_path /data/nginx/cache keys_zone=cache_zone:10m;

map $request_method $purge_method {
PURGE 1;
default 0;
}

server {
...
location / {
scgi_pass backend;
scgi_cache cache_zone;
scgi_cache_key $uri;
scgi_cache_purge $purge_method;
}
}

This functionality is available as part of our
commercial subscription.

Syntax:

scgi_cache_revalidate on | off;

Default:

scgi_cache_revalidate off;

Context:

http, server, location

This directive appeared in version 1.5.7.

Enables revalidation of expired cache items using conditional requests with
the “If-Modified-Since” and “If-None-Match”
header fields.

Syntax:

scgi_cache_use_stale
error |
timeout |
invalid_header |
updating |
http_500 |
http_503 |
http_403 |
http_404 |
http_429 |
off
...;

Default:

scgi_cache_use_stale off;

Context:

http, server, location

Determines in which cases a stale cached response can be used
when an error occurs during communication with the SCGI server.
The directive’s parameters match the parameters of the
scgi_next_upstream directive.

The error parameter also permits
using a stale cached response if an SCGI server to process a request
cannot be selected.

Additionally, the updating parameter permits
using a stale cached response if it is currently being updated.
This allows minimizing the number of accesses to SCGI servers
when updating cached data.

Using a stale cached response
can also be enabled directly in the response header
for a specified number of seconds after the response became stale (1.11.10).
This has lower priority than using the directive parameters.

The
“stale-while-revalidate”
extension of the “Cache-Control” header field permits
using a stale cached response if it is currently being updated.

The
“stale-if-error”
extension of the “Cache-Control” header field permits
using a stale cached response in case of an error.

To minimize the number of accesses to SCGI servers when
populating a new cache element, the scgi_cache_lock
directive can be used.

Syntax:

scgi_cache_valid [code ...] time;

Default:

—

Context:

http, server, location

Sets caching time for different response codes.
For example, the following directives

scgi_cache_valid 200 302 10m;
scgi_cache_valid 404 1m;

set 10 minutes of caching for responses with codes 200 and 302
and 1 minute for responses with code 404.

If only caching time is specified

scgi_cache_valid 5m;

then only 200, 301, and 302 responses are cached.

In addition, the any parameter can be specified
to cache any responses:

scgi_cache_valid 200 302 10m;
scgi_cache_valid 301 1h;
scgi_cache_valid any 1m;

Parameters of caching can also be set directly
in the response header.
This has higher priority than setting of caching time using the directive.

The “X-Accel-Expires” header field sets caching time of a
response in seconds.
The zero value disables caching for a response.
If the value starts with the @ prefix, it sets an absolute
time in seconds since Epoch, up to which the response may be cached.

If the header does not include the “X-Accel-Expires” field,
parameters of caching may be set in the header fields
“Expires” or “Cache-Control”.

If the header includes the “Set-Cookie” field, such a
response will not be cached.

If the header includes the “Vary” field
with the special value “*”, such a
response will not be cached (1.7.7).
If the header includes the “Vary” field
with another value, such a response will be cached
taking into account the corresponding request header fields (1.7.7).

Processing of one or more of these response header fields can be disabled
using the scgi_ignore_headers directive.

Syntax:

scgi_connect_timeout time;

Default:

scgi_connect_timeout 60s;

Context:

http, server, location

Defines a timeout for establishing a connection with an SCGI server.
It should be noted that this timeout cannot usually exceed 75 seconds.

Syntax:

scgi_force_ranges on | off;

Default:

scgi_force_ranges off;

Context:

http, server, location

This directive appeared in version 1.7.7.

Enables byte-range support
for both cached and uncached responses from the SCGI server
regardless of the “Accept-Ranges” field in these responses.

Syntax:

scgi_hide_header field;

Default:

—

Context:

http, server, location

By default,
nginx does not pass the header fields “Status” and
“X-Accel-...” from the response of an SCGI
server to a client.
The scgi_hide_header directive sets additional fields
that will not be passed.
If, on the contrary, the passing of fields needs to be permitted,
the scgi_pass_header directive can be used.

Syntax:

scgi_ignore_client_abort on | off;

Default:

scgi_ignore_client_abort off;

Context:

http, server, location

Determines whether the connection with an SCGI server should be
closed when a client closes the connection without waiting
for a response.

Syntax:

scgi_ignore_headers field ...;

Default:

—

Context:

http, server, location

Disables processing of certain response header fields from the SCGI server.
The following fields can be ignored: “X-Accel-Redirect”,
“X-Accel-Expires”, “X-Accel-Limit-Rate” (1.1.6),
“X-Accel-Buffering” (1.1.6),
“X-Accel-Charset” (1.1.6), “Expires”,
“Cache-Control”, “Set-Cookie” (0.8.44),
and “Vary” (1.7.7).

If not disabled, processing of these header fields has the following
effect:

“X-Accel-Expires”, “Expires”,
“Cache-Control”, “Set-Cookie”,
and “Vary”
set the parameters of response caching;

“X-Accel-Redirect” performs an
internal
redirect to the specified URI;

“X-Accel-Limit-Rate” sets the
rate
limit for transmission of a response to a client;

“X-Accel-Buffering” enables or disables
buffering of a response;

“X-Accel-Charset” sets the desired
charset
of a response.

Syntax:

scgi_intercept_errors on | off;

Default:

scgi_intercept_errors off;

Context:

http, server, location

Determines whether an SCGI server responses with codes greater than or equal
to 300 should be passed to a client
or be intercepted and redirected to nginx for processing
with the error_page directive.

Syntax:

scgi_limit_rate rate;

Default:

scgi_limit_rate 0;

Context:

http, server, location

This directive appeared in version 1.7.7.

Limits the speed of reading the response from the SCGI server.
The rate is specified in bytes per second.
The zero value disables rate limiting.
The limit is set per a request, and so if nginx simultaneously opens
two connections to the SCGI server,
the overall rate will be twice as much as the specified limit.
The limitation works only if
buffering of responses from the SCGI
server is enabled.
Parameter value can contain variables (1.27.0).

Syntax:

scgi_max_temp_file_size size;

Default:

scgi_max_temp_file_size 1024m;

Context:

http, server, location

When buffering of responses from the SCGI
server is enabled, and the whole response does not fit into the buffers
set by the scgi_buffer_size and scgi_buffers
directives, a part of the response can be saved to a temporary file.
This directive sets the maximum size of the temporary file.
The size of data written to the temporary file at a time is set
by the scgi_temp_file_write_size directive.

The zero value disables buffering of responses to temporary files.

This restriction does not apply to responses
that will be cached
or stored on disk.

Syntax:

scgi_next_upstream
error |
timeout |
denied |
invalid_header |
http_500 |
http_503 |
http_403 |
http_404 |
http_429 |
non_idempotent |
off
...;

Default:

scgi_next_upstream error timeout;

Context:

http, server, location

Specifies in which cases a request should be passed to the next server:

error

an error occurred while establishing a connection with the
server, passing a request to it, or reading the response header;

timeout

a timeout has occurred while establishing a connection with the
server, passing a request to it, or reading the response header;

denied

the server denied
the connection (1.29.3);

This parameter is available as part of our
commercial subscription.

invalid_header

a server returned an empty or invalid response;

http_500

a server returned a response with the code 500;

http_503

a server returned a response with the code 503;

http_403

a server returned a response with the code 403;

http_404

a server returned a response with the code 404;

http_429

a server returned a response with the code 429 (1.11.13);

non_idempotent

normally, requests with a
non-idempotent
method
(POST, LOCK, PATCH)
are not passed to the next server
if a request has been sent to an upstream server (1.9.13);
enabling this option explicitly allows retrying such requests;

off

disables passing a request to the next server.

One should bear in mind that passing a request to the next server is
only possible if nothing has been sent to a client yet.
That is, if an error or timeout occurs in the middle of the
transferring of a response, fixing this is impossible.

The directive also defines what is considered an
unsuccessful
attempt of communication with a server.
The cases of error, timeout,
denied and
invalid_header are always considered unsuccessful attempts,
even if they are not specified in the directive.
The cases of http_500, http_503,
and http_429 are
considered unsuccessful attempts only if they are specified in the directive.
The cases of http_403 and http_404
are never considered unsuccessful attempts.

Passing a request to the next server can be limited by
the number of tries
and by time.

Syntax:

scgi_next_upstream_timeout time;

Default:

scgi_next_upstream_timeout 0;

Context:

http, server, location

This directive appeared in version 1.7.5.

Limits the time during which a request can be passed to the
next server.
The 0 value turns off this limitation.

Syntax:

scgi_next_upstream_tries number;

Default:

scgi_next_upstream_tries 0;

Context:

http, server, location

This directive appeared in version 1.7.5.

Limits the number of possible tries for passing a request to the
next server.
The 0 value turns off this limitation.

Syntax:

scgi_no_cache string ...;

Default:

—

Context:

http, server, location

Defines conditions under which the response will not be saved to a cache.
If at least one value of the string parameters is not empty and is not
equal to “0” then the response will not be saved:

scgi_no_cache $cookie_nocache $arg_nocache$arg_comment;
scgi_no_cache $http_pragma $http_authorization;

Can be used along with the scgi_cache_bypass directive.

Syntax:

scgi_param
parameter value
[if_not_empty];

Default:

scgi_param HTTP_HOST $host$is_request_port$request_port;

Context:

http, server, location

Sets a parameter that should be passed to the SCGI server.
The value can contain text, variables, and their combination.
These directives are inherited from the previous configuration level
if and only if there are no scgi_param directives
defined on the current level.

Standard
CGI
environment variables
should be provided as SCGI headers, see the scgi_params file
provided in the distribution:

location / {
include scgi_params;
...
}

If the directive is specified with if_not_empty (1.1.11) then
such a parameter will be passed to the server only if its value is not empty:

scgi_param HTTPS $https if_not_empty;

Syntax:

scgi_pass address;

Default:

—

Context:

location, if in location

Sets the address of an SCGI server.
The address can be specified as a domain name or IP address,
and a port:

scgi_pass localhost:9000;

or as a UNIX-domain socket path:

scgi_pass unix:/tmp/scgi.socket;

If a domain name resolves to several addresses, all of them will be
used in a round-robin fashion.
In addition, an address can be specified as a
server group.

Parameter value can contain variables.
In this case, if an address is specified as a domain name,
the name is searched among the described
server groups,
and, if not found, is determined using a
resolver.

Syntax:

scgi_pass_header field;

Default:

—

Context:

http, server, location

Permits passing otherwise disabled header
fields from an SCGI server to a client.

Syntax:

scgi_pass_request_body on | off;

Default:

scgi_pass_request_body on;

Context:

http, server, location

Indicates whether the original request body is passed
to the SCGI server.
See also the scgi_pass_request_headers directive.

Syntax:

scgi_pass_request_headers on | off;

Default:

scgi_pass_request_headers on;

Context:

http, server, location

Indicates whether the header fields of the original request are passed
to the SCGI server.
See also the scgi_pass_request_body directive.

Syntax:

scgi_read_timeout time;

Default:

scgi_read_timeout 60s;

Context:

http, server, location

Defines a timeout for reading a response from the SCGI server.
The timeout is set only between two successive read operations,
not for the transmission of the whole response.
If the SCGI server does not transmit anything within this time,
the connection is closed.

Syntax:

scgi_request_buffering on | off;

Default:

scgi_request_buffering on;

Context:

http, server, location

This directive appeared in version 1.7.11.

Enables or disables buffering of a client request body.

When buffering is enabled, the entire request body is
read
from the client before sending the request to an SCGI server.

When buffering is disabled, the request body is sent to the SCGI server
immediately as it is received.
In this case, the request cannot be passed to the
next server
if nginx already started sending the request body.

When HTTP/1.1 chunked transfer encoding is used
to send the original request body,
the request body will be buffered regardless of the directive value.

Syntax:

scgi_request_dynamic on | off;

Default:

scgi_request_dynamic off;

Context:

http, server, location

This directive appeared in version 1.29.3.

Enables or disables creation of a separate request instance
for each SCGI server.
By default, a single request is used for all SCGI servers.
If enabled, a separate request instance is created,
allowing per-server request customization.

This directive is available as part of our
commercial subscription.

Syntax:

scgi_send_timeout time;

Default:

scgi_send_timeout 60s;

Context:

http, server, location

Sets a timeout for transmitting a request to the SCGI server.
The timeout is set only between two successive write operations,
not for the transmission of the whole request.
If the SCGI server does not receive anything within this time,
the connection is closed.

Syntax:

scgi_socket_keepalive on | off;

Default:

scgi_socket_keepalive off;

Context:

http, server, location

This directive appeared in version 1.15.6.

Configures the “TCP keepalive” behavior
for outgoing connections to an SCGI server.
By default, the operating system’s settings are in effect for the socket.
If the directive is set to the value “on”, the
SO_KEEPALIVE socket option is turned on for the socket.

Syntax:

scgi_store
on |
off |
string;

Default:

scgi_store off;

Context:

http, server, location

Enables saving of files to a disk.
The on parameter saves files with paths
corresponding to the directives
alias or
root.
The off parameter disables saving of files.
In addition, the file name can be set explicitly using the
string with variables:

scgi_store /data/www$original_uri;

The modification time of files is set according to the received
“Last-Modified” response header field.
The response is first written to a temporary file,
and then the file is renamed.
Starting from version 0.8.9, temporary files and the persistent store
can be put on different file systems.
However, be aware that in this case a file is copied
across two file systems instead of the cheap renaming operation.
It is thus recommended that for any given location both saved files and a
directory holding temporary files, set by the scgi_temp_path
directive, are put on the same file system.

This directive can be used to create local copies of static unchangeable
files, e.g.:

location /images/ {
root /data/www;
error_page 404 = /fetch$uri;
}

location /fetch/ {
internal;

scgi_pass backend:9000;
...

scgi_store on;
scgi_store_access user:rw group:rw all:r;
scgi_temp_path /data/temp;

alias /data/www/;
}

Syntax:

scgi_store_access users:permissions ...;

Default:

scgi_store_access user:rw;

Context:

http, server, location

Sets access permissions for newly created files and directories, e.g.:

scgi_store_access user:rw group:rw all:r;

If any group or all access permissions
are specified then user permissions may be omitted:

scgi_store_access group:rw all:r;

Syntax:

scgi_temp_file_write_size size;

Default:

scgi_temp_file_write_size 8k|16k;

Context:

http, server, location

Limits the size of data written to a temporary file
at a time, when buffering of responses from the SCGI server
to temporary files is enabled.
By default, size is limited by two buffers set by the
scgi_buffer_size and scgi_buffers directives.
The maximum size of a temporary file is set by the
scgi_max_temp_file_size directive.

Syntax:

scgi_temp_path
path
[level1
[level2
[level3]]];

Default:

scgi_temp_path scgi_temp;

Context:

http, server, location

Defines a directory for storing temporary files
with data received from SCGI servers.
Up to three-level subdirectory hierarchy can be used underneath the specified
directory.
For example, in the following configuration

scgi_temp_path /spool/nginx/scgi_temp 1 2;

a temporary file might look like this:

/spool/nginx/scgi_temp/7/45/00000123457

See also the use_temp_path parameter of the
scgi_cache_path directive.