Mercurial > hg > nginx
view src/http/modules/ngx_http_flv_module.c @ 4207:4fc91bae6f83
Better recheck of dead upstream servers.
Previously nginx used to mark backend again as live as soon as fail_timeout
passes (10s by default) since last failure. On the other hand, detecting
dead backend takes up to 60s (proxy_connect_timeout) in typical situation
"backend is down and doesn't respond to any packets". This resulted in
suboptimal behaviour in the above situation (up to 23% of requests were
directed to dead backend with default settings).
More detailed description of the problem may be found here (in Russian):
http://mailman.nginx.org/pipermail/nginx-ru/2011-August/042172.html
Fix is to only allow one request after fail_timeout passes, and
mark backend as "live" only if this request succeeds.
Note that with new code backend will not be marked "live" unless "check"
request is completed, and this may take a while in some specific workloads
(e.g. streaming). This is believed to be acceptable.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 12 Oct 2011 14:22:48 +0000 |
parents | 84905c7b2aa7 |
children | 2f8e9469b436 |
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/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static char *ngx_http_flv(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_flv_commands[] = { { ngx_string("flv"), NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS, ngx_http_flv, 0, 0, NULL }, ngx_null_command }; static u_char ngx_flv_header[] = "FLV\x1\x1\0\0\0\x9\0\0\0\x9"; static ngx_http_module_t ngx_http_flv_module_ctx = { NULL, /* 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_flv_module = { NGX_MODULE_V1, &ngx_http_flv_module_ctx, /* module context */ ngx_http_flv_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_flv_handler(ngx_http_request_t *r) { u_char *last; off_t start, len; size_t root; ngx_int_t rc; ngx_uint_t level, i; ngx_str_t path, value; ngx_log_t *log; ngx_buf_t *b; ngx_chain_t out[2]; ngx_open_file_info_t of; ngx_http_core_loc_conf_t *clcf; if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) { return NGX_HTTP_NOT_ALLOWED; } if (r->uri.data[r->uri.len - 1] == '/') { return NGX_DECLINED; } rc = ngx_http_discard_request_body(r); if (rc != NGX_OK) { return rc; } last = ngx_http_map_uri_to_path(r, &path, &root, 0); if (last == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } log = r->connection->log; path.len = last - path.data; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, log, 0, "http flv filename: \"%V\"", &path); clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); ngx_memzero(&of, sizeof(ngx_open_file_info_t)); of.read_ahead = clcf->read_ahead; of.directio = clcf->directio; of.valid = clcf->open_file_cache_valid; of.min_uses = clcf->open_file_cache_min_uses; of.errors = clcf->open_file_cache_errors; of.events = clcf->open_file_cache_events; if (ngx_open_cached_file(clcf->open_file_cache, &path, &of, r->pool) != NGX_OK) { switch (of.err) { case 0: return NGX_HTTP_INTERNAL_SERVER_ERROR; case NGX_ENOENT: case NGX_ENOTDIR: case NGX_ENAMETOOLONG: level = NGX_LOG_ERR; rc = NGX_HTTP_NOT_FOUND; break; case NGX_EACCES: level = NGX_LOG_ERR; rc = NGX_HTTP_FORBIDDEN; break; default: level = NGX_LOG_CRIT; rc = NGX_HTTP_INTERNAL_SERVER_ERROR; break; } if (rc != NGX_HTTP_NOT_FOUND || clcf->log_not_found) { ngx_log_error(level, log, of.err, "%s \"%s\" failed", of.failed, path.data); } return rc; } if (!of.is_file) { if (ngx_close_file(of.fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, ngx_close_file_n " \"%s\" failed", path.data); } return NGX_DECLINED; } r->root_tested = !r->error_page; start = 0; len = of.size; i = 1; if (r->args.len) { if (ngx_http_arg(r, (u_char *) "start", 5, &value) == NGX_OK) { start = ngx_atoof(value.data, value.len); if (start == NGX_ERROR || start >= len) { start = 0; } if (start) { len = sizeof(ngx_flv_header) - 1 + len - start; i = 0; } } } log->action = "sending flv to client"; r->headers_out.status = NGX_HTTP_OK; r->headers_out.content_length_n = len; r->headers_out.last_modified_time = of.mtime; if (ngx_http_set_content_type(r) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } if (i == 0) { b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t)); if (b == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } b->pos = ngx_flv_header; b->last = ngx_flv_header + sizeof(ngx_flv_header) - 1; b->memory = 1; out[0].buf = b; out[0].next = &out[1]; } b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t)); if (b == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } b->file = ngx_pcalloc(r->pool, sizeof(ngx_file_t)); if (b->file == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } r->allow_ranges = 1; rc = ngx_http_send_header(r); if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) { return rc; } b->file_pos = start; b->file_last = of.size; b->in_file = b->file_last ? 1: 0; b->last_buf = 1; b->last_in_chain = 1; b->file->fd = of.fd; b->file->name = path; b->file->log = log; b->file->directio = of.is_directio; out[1].buf = b; out[1].next = NULL; return ngx_http_output_filter(r, &out[i]); } static char * ngx_http_flv(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_flv_handler; return NGX_CONF_OK; }