Stream Module#
The core stream module implements basic functionality for handling TCP and UDP connections: this includes defining server blocks, traffic routing, configuring proxying, SSL/TLS support, and managing connections for streaming services, such as databases, DNS, and other protocols that operate over TCP and UDP.
The other modules in this section extend this functionality, allowing you to flexibly configure and optimize the stream server for various scenarios and requirements.
When building from the source code,
this module isn't built by default;
it should be enabled with the
‑‑with‑stream
build option.
In packages and images from our repos,
the module is included in the build.
Configuration Example#
worker_processes auto;
error_log /var/log/angie/error.log info;
events {
worker_connections 1024;
}
stream {
upstream backend {
hash $remote_addr consistent;
server backend1.example.com:12345 weight=5;
server 127.0.0.1:12345 max_fails=3 fail_timeout=30s;
server unix:/tmp/backend3;
}
upstream dns {
server 192.168.0.1:53535;
server dns.example.com:53;
}
server {
listen 12345;
proxy_connect_timeout 1s;
proxy_timeout 3s;
proxy_pass backend;
}
server {
listen 127.0.0.1:53 udp reuseport;
proxy_timeout 20s;
proxy_pass dns;
}
server {
listen [::1]:12345;
proxy_pass unix:/tmp/stream.socket;
}
}
Directives#
listen#
|
|
Default |
— |
server |
Sets the address and port for the socket on which the server will accept connections. It is possible to specify just the port. The address can also be a hostname, for example:
listen 127.0.0.1:12345;
listen *:12345;
listen 12345; # same as *:12345
listen localhost:12345;
IPv6 addresses are specified in square brackets:
listen [::1]:12345;
listen [::]:12345;
UNIX domain sockets are specified with the unix: prefix:
listen unix:/var/run/angie.sock;
Port ranges are specified with the first and last port separated by a hyphen:
listen 127.0.0.1:12345-12399;
listen 12345-12399;
Important
Different servers must listen on different address:port pairs.
|
allows specifying that all connections accepted on this port should work in SSL mode. |
|
configures a listening socket for working with datagrams. In order to handle packets from the same address and port in the same session, the reuseport parameter should also be specified. |
|
allows specifying that all connections accepted on this port should use the PROXY protocol. |
The listen directive can have several additional parameters specific to socket-related system calls.
|
sets the associated routing table, FIB (the |
|
enables "TCP Fast Open" for the listening socket and limits the maximum length for the queue of connections that have not yet completed the three-way handshake. |
Caution
Do not enable this feature unless the server can handle receiving the same SYN packet with data more than once.
|
sets the |
|
sets the receive buffer size (the |
|
sets the send buffer size (the |
|
Sets the name of accept filter (the |
|
instructs to use a deferred |
|
this parameter instructs to make a separate |
|
this parameter determines (via the |
|
this parameter instructs to create an individual listening socket for
each worker process (using the |
Caution
Inappropriate use of this option may have its security implications.
so_keepalive=on | off | [keepidle]:[keepintvl]:[keepcnt]
configures the "TCP keepalive" behavior for the listening socket.
|
if this parameter is omitted then the operating system's settings will be in effect for the socket |
|
the SO_KEEPALIVE option is turned on for the socket |
|
the SO_KEEPALIVE option is turned off for the socket |
Some operating systems support setting of TCP keepalive parameters on a
per-socket basis using the TCP_KEEPIDLE, TCP_KEEPINTVL, and
TCP_KEEPCNT socket options. On such systems (currently, Linux 2.4+,
NetBSD 5+, and FreeBSD 9.0-STABLE), they can be configured using the keepidle,
keepintvl, and keepcnt parameters. One or two parameters may be omitted, in
which case the system default setting for the corresponding socket option will
be in effect.
For example,
so_keepalive=30m::10
will set the idle timeout (TCP_KEEPIDLE) to 30 minutes, leave the probe interval (TCP_KEEPINTVL) at its system default, and set the probes count (TCP_KEEPCNT) to 10 probes.
preread_buffer_size#
Specifies a size of the preread buffer.
preread_timeout#
Specifies a timeout of the preread phase.
proxy_protocol_timeout#
Specifies a timeout for reading the PROXY protocol header to complete. If no entire header is transmitted within this time, the connection is closed.
resolver#
|
|
Default |
— |
stream, server, upstream |
Configures name servers used to resolve names of upstream servers into addresses, for example:
resolver 127.0.0.53 [::1]:5353;
The address can be specified as a domain name or IP address, with an optional port. If port is not specified, the port 53 is used. Name servers are queried in a round-robin fashion.
By default, Angie caches answers using the TTL value of a response. The optional valid parameter allows overriding it:
|
optional valid parameter allows overriding cached entry validity |
resolver 127.0.0.53 [::1]:5353 valid=30s;
By default, Angie will look up both IPv4 and IPv6 addresses while resolving.
|
disables looking up of IPv4 addresses |
|
disables looking up of IPv6 addresses |
|
optional parameter; enables the collection of DNS server request and response metrics (/status/resolvers/<zone>) in the specified zone. |
Tip
To prevent DNS spoofing, it is recommended configuring DNS servers in a properly secured trusted local network.
resolver_timeout#
Sets a timeout for name resolution, for example:
resolver_timeout 5s;
server#
Sets the configuration for a server.
server_name#
Sets names of a virtual server, for example:
server {
server_name example.com www.example.com;
}
The first name becomes the primary server name.
Server names can include an asterisk (*)
to replace the first or last part of a name:
server {
server_name example.com *.example.com www.example.*;
}
These names are called wildcard names.
The first two examples mentioned above can be combined into one:
server {
server_name .example.com;
}
You can also use regular expressions in server names by preceding the name with
a tilde (~):
server {
server_name www.example.com ~^www\d+\.example\.com$;
}
Regular expressions may include captures that can be used in other directives:
server {
server_name ~^(www\.)?(.+)$;
proxy_pass www.$2:12345;
}
Named captures in regular expressions create variables that can be used in other directives:
server {
server_name ~^(www\.)?(?<domain>.+)$;
proxy_pass www.$domain:12345;
}
If the directive's parameter is set to $hostname, the machine's hostname
is inserted.
When searching for a virtual server by name, if the name matches more than one of the specified variants (e.g., both a wildcard name and a regular expression match), the first matching variant will be chosen in the following order of priority:
The exact name
The longest wildcard name starting with an asterisk, e.g.,
*.example.comThe longest wildcard name ending with an asterisk, e.g.,
mail.*The first matching regular expression (in order of appearance in the configuration file)
Attention
For TLS connections, use the SSL Preread module instead.
server_names_hash_bucket_size#
|
|
Default |
|
stream |
Sets the bucket size for the server names hash tables. The default value depends on the size of the processor's cache line.
server_names_hash_max_size#
Sets the maximum size of the server names hash tables.
status_zone#
Allocates a shared memory zone to collect metrics for /status/stream/server_zones/<zone>.
Multiple server contexts can share the same zone for data collection.
The single-value zone syntax aggregates all metrics for its context in the same shared memory zone:
server {
listen 80;
server_name *.example.com;
status_zone single;
# ...
}
The alternative syntax uses the folowing parameters:
key |
A string with variables, whose value determines the grouping of connections in the zone. All connections producing identical values after substitution are grouped together. If substitution yields an empty value, metrics aren't updated. |
zone |
The name of the shared memory zone. |
count (optional) |
The maximum number of separate groups for collecting metrics. If new key values would exceed this limit, they are grouped under zone instead. The default value is 1. |
In the following example,
all connections sharing the same $server_addr value
are grouped into the host_zone.
Metrics are tracked separately for each unique $server_addr
until there are 10 metric groups.
Once this limit is reached,
any additional $server_addr values are included under the server_zone:
stream {
upstream backend {
server 192.168.0.1:3306;
server 192.168.0.2:3306;
# ...
}
server {
listen 3306;
proxy_pass backend;
status_zone $server_addr zone=server_zone:10;
}
}
The resulting metrics are thus split between individual servers in the API output.
stream#
Provides the configuration file context in which the stream server directives are specified.
tcp_nodelay#
Enables or disables the use of the TCP_NODELAY option. The option is enabled for both client and proxied server connections.
variables_hash_bucket_size#
Sets the bucket size for the variables hash table. The details of setting up hash tables are provided in a separate document.
variables_hash_max_size#
Sets the maximum size of the variables hash table. The details of setting up hash tables are provided in a separate document.
Built-in Variables#
The stream core module supports following variables:
$angie_version#
Angie version
$binary_remote_addr#
client address in a binary form, value's length is always 4 bytes for IPv4 addresses or 16 bytes for IPv6 addresses
$bytes_received#
number of bytes received from a client
$bytes_sent#
number of bytes sent to a client
$connection#
connection serial number
$hostname#
host name
$msec#
current time in seconds with the milliseconds resolution
$pid#
PID of the worker process
$protocol#
protocol used to communicate with the client: TCP or UDP
$proxy_protocol_addr#
client address from the PROXY protocol header
The PROXY protocol must be previously enabled by setting the proxy_protocol parameter in the listen directive.
$proxy_protocol_port#
client port from the PROXY protocol header
The PROXY protocol must be previously enabled by setting the proxy_protocol parameter in the listen directive.
$proxy_protocol_server_addr#
server address from the PROXY protocol header
The PROXY protocol must be previously enabled by setting the proxy_protocol parameter in the listen directive.
$proxy_protocol_server_port#
server port from the PROXY protocol header
The PROXY protocol must be previously enabled by setting the proxy_protocol parameter in the listen directive.
$proxy_protocol_tlv_<name>#
TLV from the PROXY Protocol header. The name can be a TLV type or its numeric value. In the latter case, the value is hexadecimal and should be prefixed with 0x:
$proxy_protocol_tlv_alpn
$proxy_protocol_tlv_0x01
SSL TLVs can also be accessed by TLV type name or its numeric value, both prefixed by ssl_:
$proxy_protocol_tlv_ssl_version
$proxy_protocol_tlv_ssl_0x21
The following TLV type names are supported:
alpn (0x01) - upper layer protocol used over the connection
authority (0x02) - host name value passed by the client
unique_id (0x05) - unique connection id
netns (0x30) - name of the namespace
ssl (0x20) - binary SSL TLV structure
The following SSL TLV type names are supported:
ssl_version (0x21) - SSL version used in client connection
ssl_cn (0x22) - SSL certificate Common Name
ssl_cipher (0x23) - name of the used cipher
ssl_sig_alg (0x24) - algorithm used to sign the certificate
ssl_key_alg (0x25) - public-key algorithm
Also, the following special SSL TLV type name is supported:
ssl_verify - client SSL certificate verification result, 0 if the client presented a certificate and it was successfully verified, non-zero otherwise.
The PROXY protocol must be previously enabled by setting the proxy_protocol parameter in the listen directive.
$remote_addr#
client address
$remote_port#
client port
$server_addr#
an address of the server which accepted a connection
Computing a value of this variable usually requires one system call. To avoid a system call, the listen directives must specify addresses and use the bind parameter.
$server_port#
port of the server which accepted a connection
$session_time#
session duration in seconds with a milliseconds resolution
$status#
session status, can be one of the following:
|
session completed successfully |
|
client data could not be parsed, for example, the PROXY protocol header |
|
access forbidden, for example, when access is limited for certain client addresses |
|
internal server error |
|
bad gateway, for example, if an upstream server could not be selected or reached |
|
service unavailable, for example, when access is limited by the number of connections |
$time_iso8601#
local time in the ISO 8601 standard format
$time_local#
local time in the Common Log Format