gRPC#

Allows passing requests to a gRPC server. The module requires the HTTP/2.

Configuration Example#

server {
    listen 9000;

    http2 on;

    location / {
        grpc_pass 127.0.0.1:9000;
    }
}

Directives#

grpc_bind#

Syntax

grpc_bind address [transparent] | off;

Default

Context

http, server, location

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

The transparent parameter allows outgoing connections to a gRPC server originate from a non-local IP address, for example, from a real IP address of a client:

grpc_bind $remote_addr transparent;

In order for this parameter to work, it is usually necessary to run Angie worker processes with the superuser privileges. On Linux it is not required as if the transparent parameter is specified, worker processes inherit the CAP_NET_RAW capability from the master process.

Important

It is necessary to configure kernel routing table to intercept network traffic from the gRPC server.

grpc_buffer_size#

Syntax

grpc_buffer_size size;

Default

grpc_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 gRPC server. The response is passed to the client synchronously, as soon as it is received.

grpc_connect_timeout#

Syntax

grpc_connect_timeout time;

Default

grpc_connect_timeout 60s;

Context

http, server, location

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

grpc_connection_drop#

Syntax

grpc_connection_drop time | on | off;

Default

grpc_connection_drop off;

Context

http, server, location

Enables termination of all connections to the proxied server after it has been removed from the group or marked as permanently unavailable by a reresolve process or the API command DELETE.

A connection is terminated when the next read or write event is processed for either the client or the proxied server.

Setting time enables a connection termination timeout; with on set, connections are dropped immediately.

grpc_hide_header#

Syntax

grpc_hide_header field;

Default

Context

http, server, location

By default, Angie does not pass the header fields "Date", "Server", and "X-Accel-..." from the response of a gRPC server to a client. The grpc_hide_header directive sets additional fields that will not be passed. If, on the contrary, the passing of fields needs to be permitted, the grpc_pass_header directive can be used.

grpc_ignore_headers#

Syntax

grpc_ignore_headers field ...;

Default

Context

http, server, location

Disables processing of certain response header fields from the gRPC server. The following fields can be ignored: "X-Accel-Redirect" and "X-Accel-Charset".

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

  • "X-Accel-Redirect" performs an internal redirect to the specified URI;

  • "X-Accel-Charset" sets the desired charset of a response.

grpc_intercept_errors#

Syntax

grpc_intercept_errors on | off;

Default

grpc_intercept_errors off;

Context

http, server, location

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

grpc_next_upstream#

Syntax

grpc_next_upstream error | timeout | invalid_header | http_500 | http_502 | http_503 | http_504 | http_403 | http_404 | http_429 | non_idempotent | off ...;

Default

grpc_next_upstream error timeout;

Context

http, server, location

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

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;

invalid_header

a server returned an empty or invalid response;

http_500

a server returned a response with the code 500;

http_502

a server returned a response with the code 502;

http_503

a server returned a response with the code 503;

http_504

a server returned a response with the code 504;

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;

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; enabling this option explicitly allows retrying such requests;

off

disables passing a request to the next server.

Note

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.

error
timeout
invalid_header

always considered unsuccessful attempts, even if they are not specified in the directive

http_500
http_502
http_503
http_504
http_429

considered unsuccessful attempts only if they are specified in the directive

http_403
http_404

never considered unsuccessful attempts

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

grpc_next_upstream_timeout#

Syntax

grpc_next_upstream_timeout time;

Default

grpc_next_upstream_timeout 0;

Context

http, server, location

Limits the time during which a request can be passed to the next server.

0

turns off this limitation

grpc_next_upstream_tries#

Syntax

grpc_next_upstream_tries number;

Default

grpc_next_upstream_tries 0;

Context

http, server, location

Limits the number of possible tries for passing a request to the next server.

0

turns off this limitation

grpc_pass#

Syntax

grpc_pass address;

Default

Context

location, if in location

Sets gRPC server address. The address can be specified as a domain name or IP address, and a port:

grpc_pass localhost:9000;

or as a UNIX domain socket path:

grpc_pass unix:/tmp/grpc.socket;

Alternatively, the "grpc://" scheme can be used:

grpc_pass grpc://127.0.0.1:9000;

To use gRPC over SSL, the "grpcs://" scheme should be used:

grpc_pass grpcs://127.0.0.1:443;

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. If a group is used, you cannot specify the port with it; instead, specify the port for each server within the group individually.

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.

grpc_pass_header#

Syntax

grpc_pass_header field ...;

Default

Context

http, server, location

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

grpc_read_timeout#

Syntax

grpc_read_timeout time;

Default

grpc_read_timeout 60s;

Context

http, server, location

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

grpc_send_timeout#

Syntax

grpc_send_timeout time;

Default

grpc_send_timeout 60s;

Context

http, server, location

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

grpc_set_header#

Syntax

grpc_set_header field value;

Default

grpc_set_header Content-Length $content_length;

Context

http, server, location

Allows redefining or appending fields to the request header passed to the gRPC server. The value can contain text, variables, and their combinations. These directives are inherited from the previous configuration level if and only if there are no grpc_set_header directives defined on the current level.

If the value of a header field is an empty string then this field will not be passed to a gRPC server:

grpc_set_header Accept-Encoding "";

grpc_socket_keepalive#

Syntax

grpc_socket_keepalive on | off;

Default

grpc_socket_keepalive off;

Context

http, server, location

Configures the "TCP keepalive" behavior for outgoing connections to a gRPC server.

""

By default, the operating system's settings are in effect for the socket.

on

The SO_KEEPALIVE socket option is turned on for the socket.

grpc_ssl_certificate#

Syntax

grpc_ssl_certificate file;

Default

Context

http, server, location

Specifies a file with the certificate in the PEM format used for authentication to a gRPC SSL server. Variables can be used in the file name.

grpc_ssl_certificate_key#

Syntax

grpc_ssl_certificate_key file;

Default

Context

http, server, location

Specifies a file with the secret key in the PEM format used for authentication to a gRPC SSL server.

The value "engine:name:id" can be specified instead of the file, which loads a secret key with a specified id from the OpenSSL engine name. Variables can be used in the file name.

grpc_ssl_ciphers#

Syntax

grpc_ssl_ciphers ciphers;

Default

grpc_ssl_ciphers DEFAULT;

Context

http, server, location

Specifies the enabled ciphers for requests to a gRPC SSL server. The ciphers are specified in the format understood by the OpenSSL library.

The full list can be viewed using the "openssl ciphers" command.

grpc_ssl_conf_command#

Syntax

grpc_ssl_conf_command name value;

Default

Context

http, server, location

Sets arbitrary OpenSSL configuration commands when establishing a connection with the gRPC SSL server.

Important

The directive is supported when using OpenSSL 1.0.2 or higher.

Several grpc_ssl_conf_command directives can be specified on the same level. These directives are inherited from the previous configuration level if and only if there are no grpc_ssl_conf_command directives defined on the current level.

Caution

Note that configuring OpenSSL directly might result in unexpected behavior.

grpc_ssl_crl#

Syntax

grpc_ssl_crl file;

Default

Context

http, server, location

Specifies a file with revoked certificates (CRL) in the PEM format used to verify the certificate of the gRPC SSL server.

grpc_ssl_name#

Syntax

grpc_ssl_name name;

Default

grpc_ssl_name `host from grpc_pass;`

Context

http, server, location

Allows overriding the server name used to verify the certificate of the gRPC SSL server and to be passed through SNI when establishing a connection with the gRPC SSL server.

By default, the host part of the grpc_pass URL is used.

grpc_ssl_password_file#

Syntax

grpc_ssl_password_file file;

Default

Context

http, server, location

Specifies a file with passphrases for secret keys where each passphrase is specified on a separate line. Passphrases are tried in turn when loading the key.

grpc_ssl_protocols#

Syntax

grpc_ssl_protocols [SSLv2] [SSLv3] [TLSv1] [TLSv1.1] [TLSv1.2] [TLSv1.3];

Default

grpc_ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3;

Context

http, server, location

Changed in version 1.2.0: TLSv1.3 parameter added to default set.

Enables the specified protocols for requests to a gRPC HTTPS server.

grpc_ssl_server_name#

Syntax

grpc_ssl_server_name on | off;

Default

grpc_ssl_server_name off;

Context

http, server, location

Enables or disables passing the server name set by the grpc_ssl_name directive via the Server Name Indication TLS extension (SNI, RFC 6066) while establishing a connection with the gRPC SSL server.

grpc_ssl_session_reuse#

Syntax

grpc_ssl_session_reuse on | off;

Default

grpc_ssl_session_reuse on;

Context

http, server, location

Determines whether SSL sessions can be reused when working with the gRPC server. If the errors "SSL3_GET_FINISHED:digest check failed" appear in the logs, try disabling session reuse.

grpc_ssl_trusted_certificate#

Syntax

grpc_ssl_trusted_certificate file;

Default

Context

http, server, location

Specifies a file with trusted CA certificates in the PEM format used to verify the certificate of the gRPC SSL server.

grpc_ssl_verify#

Syntax

grpc_ssl_verify on | off;

Default

grpc_ssl_verify off;

Context

http, server, location

Enables or disables verification of the gRPC SSL server certificate.

grpc_ssl_verify_depth#

Syntax

grpc_ssl_verify_depth number;

Default

grpc_ssl_verify_depth 1;

Context

http, server, location

Sets the verification depth in the gRPC SSL server certificates chain.