Mercurial > hg > nginx
view src/http/modules/ngx_http_stub_status_module.c @ 7235:c2a0a838c40f
gRPC: special handling of "trailer only" responses.
The gRPC protocol makes a distinction between HEADERS frame with
the END_STREAM flag set, and a HEADERS frame followed by an empty
DATA frame with the END_STREAM flag. The latter is not permitted,
and results in errors not being propagated through nginx. Instead,
gRPC clients complain that "server closed the stream without sending
trailers" (seen in grpc-go) or "13: Received RST_STREAM with error
code 2" (seen in grpc-c).
To fix this, nginx now returns HEADERS with the END_STREAM flag if
the response length is known to be 0, and we are not expecting
any trailer headers to be added. And the response length is
explicitly set to 0 in the gRPC proxy if we see initial HEADERS frame
with the END_STREAM flag set.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Sat, 17 Mar 2018 23:04:26 +0300 |
parents | 2a288909abc6 |
children | 43a0a9e988be |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static ngx_int_t ngx_http_stub_status_handler(ngx_http_request_t *r); static ngx_int_t ngx_http_stub_status_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); static ngx_int_t ngx_http_stub_status_add_variables(ngx_conf_t *cf); static char *ngx_http_set_stub_status(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_status_commands[] = { { ngx_string("stub_status"), NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS|NGX_CONF_TAKE1, ngx_http_set_stub_status, 0, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_stub_status_module_ctx = { ngx_http_stub_status_add_variables, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_stub_status_module = { NGX_MODULE_V1, &ngx_http_stub_status_module_ctx, /* module context */ ngx_http_status_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_http_variable_t ngx_http_stub_status_vars[] = { { ngx_string("connections_active"), NULL, ngx_http_stub_status_variable, 0, NGX_HTTP_VAR_NOCACHEABLE, 0 }, { ngx_string("connections_reading"), NULL, ngx_http_stub_status_variable, 1, NGX_HTTP_VAR_NOCACHEABLE, 0 }, { ngx_string("connections_writing"), NULL, ngx_http_stub_status_variable, 2, NGX_HTTP_VAR_NOCACHEABLE, 0 }, { ngx_string("connections_waiting"), NULL, ngx_http_stub_status_variable, 3, NGX_HTTP_VAR_NOCACHEABLE, 0 }, ngx_http_null_variable }; static ngx_int_t ngx_http_stub_status_handler(ngx_http_request_t *r) { size_t size; ngx_int_t rc; ngx_buf_t *b; ngx_chain_t out; ngx_atomic_int_t ap, hn, ac, rq, rd, wr, wa; if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) { return NGX_HTTP_NOT_ALLOWED; } rc = ngx_http_discard_request_body(r); if (rc != NGX_OK) { return rc; } r->headers_out.content_type_len = sizeof("text/plain") - 1; ngx_str_set(&r->headers_out.content_type, "text/plain"); r->headers_out.content_type_lowcase = NULL; if (r->method == NGX_HTTP_HEAD) { r->headers_out.status = NGX_HTTP_OK; rc = ngx_http_send_header(r); if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) { return rc; } } size = sizeof("Active connections: \n") + NGX_ATOMIC_T_LEN + sizeof("server accepts handled requests\n") - 1 + 6 + 3 * NGX_ATOMIC_T_LEN + sizeof("Reading: Writing: Waiting: \n") + 3 * NGX_ATOMIC_T_LEN; b = ngx_create_temp_buf(r->pool, size); if (b == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } out.buf = b; out.next = NULL; ap = *ngx_stat_accepted; hn = *ngx_stat_handled; ac = *ngx_stat_active; rq = *ngx_stat_requests; rd = *ngx_stat_reading; wr = *ngx_stat_writing; wa = *ngx_stat_waiting; b->last = ngx_sprintf(b->last, "Active connections: %uA \n", ac); b->last = ngx_cpymem(b->last, "server accepts handled requests\n", sizeof("server accepts handled requests\n") - 1); b->last = ngx_sprintf(b->last, " %uA %uA %uA \n", ap, hn, rq); b->last = ngx_sprintf(b->last, "Reading: %uA Writing: %uA Waiting: %uA \n", rd, wr, wa); r->headers_out.status = NGX_HTTP_OK; r->headers_out.content_length_n = b->last - b->pos; b->last_buf = (r == r->main) ? 1 : 0; b->last_in_chain = 1; rc = ngx_http_send_header(r); if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) { return rc; } return ngx_http_output_filter(r, &out); } static ngx_int_t ngx_http_stub_status_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { u_char *p; ngx_atomic_int_t value; p = ngx_pnalloc(r->pool, NGX_ATOMIC_T_LEN); if (p == NULL) { return NGX_ERROR; } switch (data) { case 0: value = *ngx_stat_active; break; case 1: value = *ngx_stat_reading; break; case 2: value = *ngx_stat_writing; break; case 3: value = *ngx_stat_waiting; break; /* suppress warning */ default: value = 0; break; } v->len = ngx_sprintf(p, "%uA", value) - p; v->valid = 1; v->no_cacheable = 0; v->not_found = 0; v->data = p; return NGX_OK; } static ngx_int_t ngx_http_stub_status_add_variables(ngx_conf_t *cf) { ngx_http_variable_t *var, *v; for (v = ngx_http_stub_status_vars; v->name.len; v++) { var = ngx_http_add_variable(cf, &v->name, v->flags); if (var == NULL) { return NGX_ERROR; } var->get_handler = v->get_handler; var->data = v->data; } return NGX_OK; } static char * ngx_http_set_stub_status(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_core_loc_conf_t *clcf; clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module); clcf->handler = ngx_http_stub_status_handler; return NGX_CONF_OK; }