Mercurial > hg > nginx
view src/http/modules/ngx_http_addition_filter_module.c @ 8045:aa28c802409f
Resolver: make TCP write timer event cancelable.
Similar to 70e65bf8dfd7, the change is made to ensure that the ability to
cancel resolver tasks is fully controlled by the caller. As mentioned in the
referenced commit, it is safe to make this timer cancelable because resolve
tasks can have their own timeouts that are not cancelable.
The scenario where this may become a problem is a periodic background resolve
task (not tied to a specific request or a client connection), which receives a
response with short TTL, large enough to warrant fallback to a TCP query.
With each event loop wakeup, we either have a previously set write timer
instance or schedule a new one. The non-cancelable write timer can delay or
block graceful shutdown of a worker even if the ngx_resolver_ctx_t->cancelable
flag is set by the API user, and there are no other tasks or connections.
We use the resolver API in this way to maintain the list of upstream server
addresses specified with the 'resolve' parameter, and there could be third-party
modules implementing similar logic.
author | Aleksei Bavshin <a.bavshin@f5.com> |
---|---|
date | Wed, 01 Jun 2022 20:17:23 -0700 |
parents | f583559aadc7 |
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 { ngx_str_t before_body; ngx_str_t after_body; ngx_hash_t types; ngx_array_t *types_keys; } ngx_http_addition_conf_t; typedef struct { ngx_uint_t before_body_sent; } ngx_http_addition_ctx_t; static void *ngx_http_addition_create_conf(ngx_conf_t *cf); static char *ngx_http_addition_merge_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_addition_filter_init(ngx_conf_t *cf); static ngx_command_t ngx_http_addition_commands[] = { { ngx_string("add_before_body"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_str_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_addition_conf_t, before_body), NULL }, { ngx_string("add_after_body"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_str_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_addition_conf_t, after_body), NULL }, { ngx_string("addition_types"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE, ngx_http_types_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_addition_conf_t, types_keys), &ngx_http_html_default_types[0] }, ngx_null_command }; static ngx_http_module_t ngx_http_addition_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_addition_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_addition_create_conf, /* create location configuration */ ngx_http_addition_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_addition_filter_module = { NGX_MODULE_V1, &ngx_http_addition_filter_module_ctx, /* module context */ ngx_http_addition_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_output_header_filter_pt ngx_http_next_header_filter; static ngx_http_output_body_filter_pt ngx_http_next_body_filter; static ngx_int_t ngx_http_addition_header_filter(ngx_http_request_t *r) { ngx_http_addition_ctx_t *ctx; ngx_http_addition_conf_t *conf; if (r->headers_out.status != NGX_HTTP_OK || r != r->main) { return ngx_http_next_header_filter(r); } conf = ngx_http_get_module_loc_conf(r, ngx_http_addition_filter_module); if (conf->before_body.len == 0 && conf->after_body.len == 0) { return ngx_http_next_header_filter(r); } if (ngx_http_test_content_type(r, &conf->types) == NULL) { return ngx_http_next_header_filter(r); } ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_addition_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } ngx_http_set_ctx(r, ctx, ngx_http_addition_filter_module); ngx_http_clear_content_length(r); ngx_http_clear_accept_ranges(r); ngx_http_weak_etag(r); r->preserve_body = 1; return ngx_http_next_header_filter(r); } static ngx_int_t ngx_http_addition_body_filter(ngx_http_request_t *r, ngx_chain_t *in) { ngx_int_t rc; ngx_uint_t last; ngx_chain_t *cl; ngx_http_request_t *sr; ngx_http_addition_ctx_t *ctx; ngx_http_addition_conf_t *conf; if (in == NULL || r->header_only) { return ngx_http_next_body_filter(r, in); } ctx = ngx_http_get_module_ctx(r, ngx_http_addition_filter_module); if (ctx == NULL) { return ngx_http_next_body_filter(r, in); } conf = ngx_http_get_module_loc_conf(r, ngx_http_addition_filter_module); if (!ctx->before_body_sent) { ctx->before_body_sent = 1; if (conf->before_body.len) { if (ngx_http_subrequest(r, &conf->before_body, NULL, &sr, NULL, 0) != NGX_OK) { return NGX_ERROR; } } } if (conf->after_body.len == 0) { ngx_http_set_ctx(r, NULL, ngx_http_addition_filter_module); return ngx_http_next_body_filter(r, in); } last = 0; for (cl = in; cl; cl = cl->next) { if (cl->buf->last_buf) { cl->buf->last_buf = 0; cl->buf->last_in_chain = 1; cl->buf->sync = 1; last = 1; } } rc = ngx_http_next_body_filter(r, in); if (rc == NGX_ERROR || !last || conf->after_body.len == 0) { return rc; } if (ngx_http_subrequest(r, &conf->after_body, NULL, &sr, NULL, 0) != NGX_OK) { return NGX_ERROR; } ngx_http_set_ctx(r, NULL, ngx_http_addition_filter_module); return ngx_http_send_special(r, NGX_HTTP_LAST); } static ngx_int_t ngx_http_addition_filter_init(ngx_conf_t *cf) { ngx_http_next_header_filter = ngx_http_top_header_filter; ngx_http_top_header_filter = ngx_http_addition_header_filter; ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_addition_body_filter; return NGX_OK; } static void * ngx_http_addition_create_conf(ngx_conf_t *cf) { ngx_http_addition_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_addition_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->before_body = { 0, NULL }; * conf->after_body = { 0, NULL }; * conf->types = { NULL }; * conf->types_keys = NULL; */ return conf; } static char * ngx_http_addition_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_addition_conf_t *prev = parent; ngx_http_addition_conf_t *conf = child; ngx_conf_merge_str_value(conf->before_body, prev->before_body, ""); ngx_conf_merge_str_value(conf->after_body, prev->after_body, ""); if (ngx_http_merge_types(cf, &conf->types_keys, &conf->types, &prev->types_keys, &prev->types, ngx_http_html_default_types) != NGX_OK) { return NGX_CONF_ERROR; } return NGX_CONF_OK; }