Mercurial > hg > nginx
view src/http/modules/ngx_http_memcached_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 | d26db4f82d7d |
children |
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> typedef struct { ngx_http_upstream_conf_t upstream; ngx_int_t index; ngx_uint_t gzip_flag; } ngx_http_memcached_loc_conf_t; typedef struct { size_t rest; ngx_http_request_t *request; ngx_str_t key; } ngx_http_memcached_ctx_t; static ngx_int_t ngx_http_memcached_create_request(ngx_http_request_t *r); static ngx_int_t ngx_http_memcached_reinit_request(ngx_http_request_t *r); static ngx_int_t ngx_http_memcached_process_header(ngx_http_request_t *r); static ngx_int_t ngx_http_memcached_filter_init(void *data); static ngx_int_t ngx_http_memcached_filter(void *data, ssize_t bytes); static void ngx_http_memcached_abort_request(ngx_http_request_t *r); static void ngx_http_memcached_finalize_request(ngx_http_request_t *r, ngx_int_t rc); static void *ngx_http_memcached_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_memcached_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child); static char *ngx_http_memcached_pass(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_conf_bitmask_t ngx_http_memcached_next_upstream_masks[] = { { ngx_string("error"), NGX_HTTP_UPSTREAM_FT_ERROR }, { ngx_string("timeout"), NGX_HTTP_UPSTREAM_FT_TIMEOUT }, { ngx_string("invalid_response"), NGX_HTTP_UPSTREAM_FT_INVALID_HEADER }, { ngx_string("not_found"), NGX_HTTP_UPSTREAM_FT_HTTP_404 }, { ngx_string("off"), NGX_HTTP_UPSTREAM_FT_OFF }, { ngx_null_string, 0 } }; static ngx_command_t ngx_http_memcached_commands[] = { { ngx_string("memcached_pass"), NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF|NGX_CONF_TAKE1, ngx_http_memcached_pass, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("memcached_bind"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE12, ngx_http_upstream_bind_set_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, upstream.local), NULL }, { ngx_string("memcached_socket_keepalive"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG, ngx_conf_set_flag_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, upstream.socket_keepalive), NULL }, { ngx_string("memcached_connect_timeout"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_msec_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, upstream.connect_timeout), NULL }, { ngx_string("memcached_send_timeout"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_msec_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, upstream.send_timeout), NULL }, { ngx_string("memcached_buffer_size"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_size_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, upstream.buffer_size), NULL }, { ngx_string("memcached_read_timeout"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_msec_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, upstream.read_timeout), NULL }, { ngx_string("memcached_next_upstream"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE, ngx_conf_set_bitmask_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, upstream.next_upstream), &ngx_http_memcached_next_upstream_masks }, { ngx_string("memcached_next_upstream_tries"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_num_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, upstream.next_upstream_tries), NULL }, { ngx_string("memcached_next_upstream_timeout"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_msec_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, upstream.next_upstream_timeout), NULL }, { ngx_string("memcached_gzip_flag"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_num_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_memcached_loc_conf_t, gzip_flag), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_memcached_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_memcached_create_loc_conf, /* create location configuration */ ngx_http_memcached_merge_loc_conf /* merge location configuration */ }; ngx_module_t ngx_http_memcached_module = { NGX_MODULE_V1, &ngx_http_memcached_module_ctx, /* module context */ ngx_http_memcached_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_str_t ngx_http_memcached_key = ngx_string("memcached_key"); #define NGX_HTTP_MEMCACHED_END (sizeof(ngx_http_memcached_end) - 1) static u_char ngx_http_memcached_end[] = CRLF "END" CRLF; static ngx_int_t ngx_http_memcached_handler(ngx_http_request_t *r) { ngx_int_t rc; ngx_http_upstream_t *u; ngx_http_memcached_ctx_t *ctx; ngx_http_memcached_loc_conf_t *mlcf; 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; } if (ngx_http_set_content_type(r) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } if (ngx_http_upstream_create(r) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } u = r->upstream; ngx_str_set(&u->schema, "memcached://"); u->output.tag = (ngx_buf_tag_t) &ngx_http_memcached_module; mlcf = ngx_http_get_module_loc_conf(r, ngx_http_memcached_module); u->conf = &mlcf->upstream; u->create_request = ngx_http_memcached_create_request; u->reinit_request = ngx_http_memcached_reinit_request; u->process_header = ngx_http_memcached_process_header; u->abort_request = ngx_http_memcached_abort_request; u->finalize_request = ngx_http_memcached_finalize_request; ctx = ngx_palloc(r->pool, sizeof(ngx_http_memcached_ctx_t)); if (ctx == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } ctx->request = r; ngx_http_set_ctx(r, ctx, ngx_http_memcached_module); u->input_filter_init = ngx_http_memcached_filter_init; u->input_filter = ngx_http_memcached_filter; u->input_filter_ctx = ctx; r->main->count++; ngx_http_upstream_init(r); return NGX_DONE; } static ngx_int_t ngx_http_memcached_create_request(ngx_http_request_t *r) { size_t len; uintptr_t escape; ngx_buf_t *b; ngx_chain_t *cl; ngx_http_memcached_ctx_t *ctx; ngx_http_variable_value_t *vv; ngx_http_memcached_loc_conf_t *mlcf; mlcf = ngx_http_get_module_loc_conf(r, ngx_http_memcached_module); vv = ngx_http_get_indexed_variable(r, mlcf->index); if (vv == NULL || vv->not_found || vv->len == 0) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "the \"$memcached_key\" variable is not set"); return NGX_ERROR; } escape = 2 * ngx_escape_uri(NULL, vv->data, vv->len, NGX_ESCAPE_MEMCACHED); len = sizeof("get ") - 1 + vv->len + escape + sizeof(CRLF) - 1; b = ngx_create_temp_buf(r->pool, len); if (b == NULL) { return NGX_ERROR; } cl = ngx_alloc_chain_link(r->pool); if (cl == NULL) { return NGX_ERROR; } cl->buf = b; cl->next = NULL; r->upstream->request_bufs = cl; *b->last++ = 'g'; *b->last++ = 'e'; *b->last++ = 't'; *b->last++ = ' '; ctx = ngx_http_get_module_ctx(r, ngx_http_memcached_module); ctx->key.data = b->last; if (escape == 0) { b->last = ngx_copy(b->last, vv->data, vv->len); } else { b->last = (u_char *) ngx_escape_uri(b->last, vv->data, vv->len, NGX_ESCAPE_MEMCACHED); } ctx->key.len = b->last - ctx->key.data; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http memcached request: \"%V\"", &ctx->key); *b->last++ = CR; *b->last++ = LF; return NGX_OK; } static ngx_int_t ngx_http_memcached_reinit_request(ngx_http_request_t *r) { return NGX_OK; } static ngx_int_t ngx_http_memcached_process_header(ngx_http_request_t *r) { u_char *p, *start; ngx_str_t line; ngx_uint_t flags; ngx_table_elt_t *h; ngx_http_upstream_t *u; ngx_http_memcached_ctx_t *ctx; ngx_http_memcached_loc_conf_t *mlcf; u = r->upstream; for (p = u->buffer.pos; p < u->buffer.last; p++) { if (*p == LF) { goto found; } } return NGX_AGAIN; found: line.data = u->buffer.pos; line.len = p - u->buffer.pos; if (line.len == 0 || *(p - 1) != CR) { goto no_valid; } *p = '\0'; line.len--; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "memcached: \"%V\"", &line); p = u->buffer.pos; ctx = ngx_http_get_module_ctx(r, ngx_http_memcached_module); mlcf = ngx_http_get_module_loc_conf(r, ngx_http_memcached_module); if (ngx_strncmp(p, "VALUE ", sizeof("VALUE ") - 1) == 0) { p += sizeof("VALUE ") - 1; if (ngx_strncmp(p, ctx->key.data, ctx->key.len) != 0) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "memcached sent invalid key in response \"%V\" " "for key \"%V\"", &line, &ctx->key); return NGX_HTTP_UPSTREAM_INVALID_HEADER; } p += ctx->key.len; if (*p++ != ' ') { goto no_valid; } /* flags */ start = p; while (*p) { if (*p++ == ' ') { if (mlcf->gzip_flag) { goto flags; } else { goto length; } } } goto no_valid; flags: flags = ngx_atoi(start, p - start - 1); if (flags == (ngx_uint_t) NGX_ERROR) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "memcached sent invalid flags in response \"%V\" " "for key \"%V\"", &line, &ctx->key); return NGX_HTTP_UPSTREAM_INVALID_HEADER; } if (flags & mlcf->gzip_flag) { h = ngx_list_push(&r->headers_out.headers); if (h == NULL) { return NGX_ERROR; } h->hash = 1; h->next = NULL; ngx_str_set(&h->key, "Content-Encoding"); ngx_str_set(&h->value, "gzip"); r->headers_out.content_encoding = h; } length: start = p; p = line.data + line.len; u->headers_in.content_length_n = ngx_atoof(start, p - start); if (u->headers_in.content_length_n == NGX_ERROR) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "memcached sent invalid length in response \"%V\" " "for key \"%V\"", &line, &ctx->key); return NGX_HTTP_UPSTREAM_INVALID_HEADER; } u->headers_in.status_n = 200; u->state->status = 200; u->buffer.pos = p + sizeof(CRLF) - 1; return NGX_OK; } if (ngx_strcmp(p, "END\x0d") == 0) { ngx_log_error(NGX_LOG_INFO, r->connection->log, 0, "key: \"%V\" was not found by memcached", &ctx->key); u->headers_in.content_length_n = 0; u->headers_in.status_n = 404; u->state->status = 404; u->buffer.pos = p + sizeof("END" CRLF) - 1; u->keepalive = 1; return NGX_OK; } no_valid: ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "memcached sent invalid response: \"%V\"", &line); return NGX_HTTP_UPSTREAM_INVALID_HEADER; } static ngx_int_t ngx_http_memcached_filter_init(void *data) { ngx_http_memcached_ctx_t *ctx = data; ngx_http_upstream_t *u; u = ctx->request->upstream; if (u->headers_in.status_n != 404) { u->length = u->headers_in.content_length_n + NGX_HTTP_MEMCACHED_END; ctx->rest = NGX_HTTP_MEMCACHED_END; } else { u->length = 0; } return NGX_OK; } static ngx_int_t ngx_http_memcached_filter(void *data, ssize_t bytes) { ngx_http_memcached_ctx_t *ctx = data; u_char *last; ngx_buf_t *b; ngx_chain_t *cl, **ll; ngx_http_upstream_t *u; u = ctx->request->upstream; b = &u->buffer; if (u->length == (ssize_t) ctx->rest) { if (bytes > u->length || ngx_strncmp(b->last, ngx_http_memcached_end + NGX_HTTP_MEMCACHED_END - ctx->rest, bytes) != 0) { ngx_log_error(NGX_LOG_ERR, ctx->request->connection->log, 0, "memcached sent invalid trailer"); u->length = 0; ctx->rest = 0; return NGX_OK; } u->length -= bytes; ctx->rest -= bytes; if (u->length == 0) { u->keepalive = 1; } return NGX_OK; } for (cl = u->out_bufs, ll = &u->out_bufs; cl; cl = cl->next) { ll = &cl->next; } cl = ngx_chain_get_free_buf(ctx->request->pool, &u->free_bufs); if (cl == NULL) { return NGX_ERROR; } cl->buf->flush = 1; cl->buf->memory = 1; *ll = cl; last = b->last; cl->buf->pos = last; b->last += bytes; cl->buf->last = b->last; cl->buf->tag = u->output.tag; ngx_log_debug4(NGX_LOG_DEBUG_HTTP, ctx->request->connection->log, 0, "memcached filter bytes:%z size:%z length:%O rest:%z", bytes, b->last - b->pos, u->length, ctx->rest); if (bytes <= (ssize_t) (u->length - NGX_HTTP_MEMCACHED_END)) { u->length -= bytes; return NGX_OK; } last += (size_t) (u->length - NGX_HTTP_MEMCACHED_END); if (bytes > u->length || ngx_strncmp(last, ngx_http_memcached_end, b->last - last) != 0) { ngx_log_error(NGX_LOG_ERR, ctx->request->connection->log, 0, "memcached sent invalid trailer"); b->last = last; cl->buf->last = last; u->length = 0; ctx->rest = 0; return NGX_OK; } ctx->rest -= b->last - last; b->last = last; cl->buf->last = last; u->length = ctx->rest; if (u->length == 0) { u->keepalive = 1; } return NGX_OK; } static void ngx_http_memcached_abort_request(ngx_http_request_t *r) { ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "abort http memcached request"); return; } static void ngx_http_memcached_finalize_request(ngx_http_request_t *r, ngx_int_t rc) { ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "finalize http memcached request"); return; } static void * ngx_http_memcached_create_loc_conf(ngx_conf_t *cf) { ngx_http_memcached_loc_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_memcached_loc_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->upstream.bufs.num = 0; * conf->upstream.next_upstream = 0; * conf->upstream.temp_path = NULL; */ conf->upstream.local = NGX_CONF_UNSET_PTR; conf->upstream.socket_keepalive = NGX_CONF_UNSET; conf->upstream.next_upstream_tries = NGX_CONF_UNSET_UINT; conf->upstream.connect_timeout = NGX_CONF_UNSET_MSEC; conf->upstream.send_timeout = NGX_CONF_UNSET_MSEC; conf->upstream.read_timeout = NGX_CONF_UNSET_MSEC; conf->upstream.next_upstream_timeout = NGX_CONF_UNSET_MSEC; conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE; /* the hardcoded values */ conf->upstream.cyclic_temp_file = 0; conf->upstream.buffering = 0; conf->upstream.ignore_client_abort = 0; conf->upstream.send_lowat = 0; conf->upstream.bufs.num = 0; conf->upstream.busy_buffers_size = 0; conf->upstream.max_temp_file_size = 0; conf->upstream.temp_file_write_size = 0; conf->upstream.intercept_errors = 1; conf->upstream.intercept_404 = 1; conf->upstream.pass_request_headers = 0; conf->upstream.pass_request_body = 0; conf->upstream.force_ranges = 1; conf->index = NGX_CONF_UNSET; conf->gzip_flag = NGX_CONF_UNSET_UINT; return conf; } static char * ngx_http_memcached_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_memcached_loc_conf_t *prev = parent; ngx_http_memcached_loc_conf_t *conf = child; ngx_conf_merge_ptr_value(conf->upstream.local, prev->upstream.local, NULL); ngx_conf_merge_value(conf->upstream.socket_keepalive, prev->upstream.socket_keepalive, 0); ngx_conf_merge_uint_value(conf->upstream.next_upstream_tries, prev->upstream.next_upstream_tries, 0); ngx_conf_merge_msec_value(conf->upstream.connect_timeout, prev->upstream.connect_timeout, 60000); ngx_conf_merge_msec_value(conf->upstream.send_timeout, prev->upstream.send_timeout, 60000); ngx_conf_merge_msec_value(conf->upstream.read_timeout, prev->upstream.read_timeout, 60000); ngx_conf_merge_msec_value(conf->upstream.next_upstream_timeout, prev->upstream.next_upstream_timeout, 0); ngx_conf_merge_size_value(conf->upstream.buffer_size, prev->upstream.buffer_size, (size_t) ngx_pagesize); ngx_conf_merge_bitmask_value(conf->upstream.next_upstream, prev->upstream.next_upstream, (NGX_CONF_BITMASK_SET |NGX_HTTP_UPSTREAM_FT_ERROR |NGX_HTTP_UPSTREAM_FT_TIMEOUT)); if (conf->upstream.next_upstream & NGX_HTTP_UPSTREAM_FT_OFF) { conf->upstream.next_upstream = NGX_CONF_BITMASK_SET |NGX_HTTP_UPSTREAM_FT_OFF; } if (conf->upstream.upstream == NULL) { conf->upstream.upstream = prev->upstream.upstream; } if (conf->index == NGX_CONF_UNSET) { conf->index = prev->index; } ngx_conf_merge_uint_value(conf->gzip_flag, prev->gzip_flag, 0); return NGX_CONF_OK; } static char * ngx_http_memcached_pass(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_memcached_loc_conf_t *mlcf = conf; ngx_str_t *value; ngx_url_t u; ngx_http_core_loc_conf_t *clcf; if (mlcf->upstream.upstream) { return "is duplicate"; } value = cf->args->elts; ngx_memzero(&u, sizeof(ngx_url_t)); u.url = value[1]; u.no_resolve = 1; mlcf->upstream.upstream = ngx_http_upstream_add(cf, &u, 0); if (mlcf->upstream.upstream == NULL) { return NGX_CONF_ERROR; } clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module); clcf->handler = ngx_http_memcached_handler; if (clcf->name.len && clcf->name.data[clcf->name.len - 1] == '/') { clcf->auto_redirect = 1; } mlcf->index = ngx_http_get_variable_index(cf, &ngx_http_memcached_key); if (mlcf->index == NGX_ERROR) { return NGX_CONF_ERROR; } return NGX_CONF_OK; }