Mercurial > hg > nginx
view src/http/modules/ngx_http_degradation_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 | 67653855682e |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { size_t sbrk_size; } ngx_http_degradation_main_conf_t; typedef struct { ngx_uint_t degrade; } ngx_http_degradation_loc_conf_t; static ngx_conf_enum_t ngx_http_degrade[] = { { ngx_string("204"), 204 }, { ngx_string("444"), 444 }, { ngx_null_string, 0 } }; static void *ngx_http_degradation_create_main_conf(ngx_conf_t *cf); static void *ngx_http_degradation_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_degradation_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child); static char *ngx_http_degradation(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_int_t ngx_http_degradation_init(ngx_conf_t *cf); static ngx_command_t ngx_http_degradation_commands[] = { { ngx_string("degradation"), NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1, ngx_http_degradation, NGX_HTTP_MAIN_CONF_OFFSET, 0, NULL }, { ngx_string("degrade"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_enum_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_degradation_loc_conf_t, degrade), &ngx_http_degrade }, ngx_null_command }; static ngx_http_module_t ngx_http_degradation_module_ctx = { NULL, /* preconfiguration */ ngx_http_degradation_init, /* postconfiguration */ ngx_http_degradation_create_main_conf, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_degradation_create_loc_conf, /* create location configuration */ ngx_http_degradation_merge_loc_conf /* merge location configuration */ }; ngx_module_t ngx_http_degradation_module = { NGX_MODULE_V1, &ngx_http_degradation_module_ctx, /* module context */ ngx_http_degradation_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_int_t ngx_http_degradation_handler(ngx_http_request_t *r) { ngx_http_degradation_loc_conf_t *dlcf; dlcf = ngx_http_get_module_loc_conf(r, ngx_http_degradation_module); if (dlcf->degrade && ngx_http_degraded(r)) { return dlcf->degrade; } return NGX_DECLINED; } ngx_uint_t ngx_http_degraded(ngx_http_request_t *r) { time_t now; ngx_uint_t log; static size_t sbrk_size; static time_t sbrk_time; ngx_http_degradation_main_conf_t *dmcf; dmcf = ngx_http_get_module_main_conf(r, ngx_http_degradation_module); if (dmcf->sbrk_size) { log = 0; now = ngx_time(); /* lock mutex */ if (now != sbrk_time) { /* * ELF/i386 is loaded at 0x08000000, 128M * ELF/amd64 is loaded at 0x00400000, 4M * * use a function address to subtract the loading address */ sbrk_size = (size_t) sbrk(0) - ((uintptr_t) ngx_palloc & ~0x3FFFFF); sbrk_time = now; log = 1; } /* unlock mutex */ if (sbrk_size >= dmcf->sbrk_size) { if (log) { ngx_log_error(NGX_LOG_NOTICE, r->connection->log, 0, "degradation sbrk:%uzM", sbrk_size / (1024 * 1024)); } return 1; } } return 0; } static void * ngx_http_degradation_create_main_conf(ngx_conf_t *cf) { ngx_http_degradation_main_conf_t *dmcf; dmcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_degradation_main_conf_t)); if (dmcf == NULL) { return NULL; } return dmcf; } static void * ngx_http_degradation_create_loc_conf(ngx_conf_t *cf) { ngx_http_degradation_loc_conf_t *conf; conf = ngx_palloc(cf->pool, sizeof(ngx_http_degradation_loc_conf_t)); if (conf == NULL) { return NULL; } conf->degrade = NGX_CONF_UNSET_UINT; return conf; } static char * ngx_http_degradation_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_degradation_loc_conf_t *prev = parent; ngx_http_degradation_loc_conf_t *conf = child; ngx_conf_merge_uint_value(conf->degrade, prev->degrade, 0); return NGX_CONF_OK; } static char * ngx_http_degradation(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_degradation_main_conf_t *dmcf = conf; ngx_str_t *value, s; value = cf->args->elts; if (ngx_strncmp(value[1].data, "sbrk=", 5) == 0) { s.len = value[1].len - 5; s.data = value[1].data + 5; dmcf->sbrk_size = ngx_parse_size(&s); if (dmcf->sbrk_size == (size_t) NGX_ERROR) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid sbrk size \"%V\"", &value[1]); return NGX_CONF_ERROR; } return NGX_CONF_OK; } ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameter \"%V\"", &value[1]); return NGX_CONF_ERROR; } static ngx_int_t ngx_http_degradation_init(ngx_conf_t *cf) { ngx_http_handler_pt *h; ngx_http_core_main_conf_t *cmcf; cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module); h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers); if (h == NULL) { return NGX_ERROR; } *h = ngx_http_degradation_handler; return NGX_OK; }