diff options
Diffstat (limited to 'modules/proxy/balancers/mod_lbmethod_heartbeat.c')
| -rw-r--r-- | modules/proxy/balancers/mod_lbmethod_heartbeat.c | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/modules/proxy/balancers/mod_lbmethod_heartbeat.c b/modules/proxy/balancers/mod_lbmethod_heartbeat.c new file mode 100644 index 0000000..5f4873a --- /dev/null +++ b/modules/proxy/balancers/mod_lbmethod_heartbeat.c @@ -0,0 +1,466 @@ +/* Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "mod_proxy.h" +#include "scoreboard.h" +#include "ap_mpm.h" +#include "apr_version.h" +#include "ap_hooks.h" +#include "ap_slotmem.h" +#include "heartbeat.h" + +#ifndef LBM_HEARTBEAT_MAX_LASTSEEN +/* If we haven't seen a heartbeat in the last N seconds, don't count this IP + * as allive. + */ +#define LBM_HEARTBEAT_MAX_LASTSEEN (10) +#endif + +module AP_MODULE_DECLARE_DATA lbmethod_heartbeat_module; + +static int (*ap_proxy_retry_worker_fn)(const char *proxy_function, + proxy_worker *worker, server_rec *s) = NULL; + +static const ap_slotmem_provider_t *storage = NULL; +static ap_slotmem_instance_t *hm_serversmem = NULL; + +/* + * configuration structure + * path: path of the file where the heartbeat information is stored. + */ +typedef struct lb_hb_ctx_t +{ + const char *path; +} lb_hb_ctx_t; + +typedef struct hb_server_t { + const char *ip; + int busy; + int ready; + int port; + int id; + apr_time_t seen; + proxy_worker *worker; +} hb_server_t; + +typedef struct ctx_servers { + apr_time_t now; + apr_hash_t *servers; +} ctx_servers_t; + +static void +argstr_to_table(apr_pool_t *p, char *str, apr_table_t *parms) +{ + char *key; + char *value; + char *strtok_state; + + key = apr_strtok(str, "&", &strtok_state); + while (key) { + value = strchr(key, '='); + if (value) { + *value = '\0'; /* Split the string in two */ + value++; /* Skip passed the = */ + } + else { + value = "1"; + } + ap_unescape_url(key); + ap_unescape_url(value); + apr_table_set(parms, key, value); + /* + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(03230) + "Found query arg: %s = %s", key, value); + */ + key = apr_strtok(NULL, "&", &strtok_state); + } +} + +static apr_status_t readfile_heartbeats(const char *path, apr_hash_t *servers, + apr_pool_t *pool) +{ + apr_finfo_t fi; + apr_status_t rv; + apr_file_t *fp; + + if (!path) { + return APR_SUCCESS; + } + + rv = apr_file_open(&fp, path, APR_READ|APR_BINARY|APR_BUFFERED, + APR_OS_DEFAULT, pool); + + if (rv) { + return rv; + } + + rv = apr_file_info_get(&fi, APR_FINFO_SIZE, fp); + + if (rv) { + return rv; + } + + { + char *t; + int lineno = 0; + apr_bucket_alloc_t *ba = apr_bucket_alloc_create(pool); + apr_bucket_brigade *bb = apr_brigade_create(pool, ba); + apr_bucket_brigade *tmpbb = apr_brigade_create(pool, ba); + apr_table_t *hbt = apr_table_make(pool, 10); + + apr_brigade_insert_file(bb, fp, 0, fi.size, pool); + + do { + hb_server_t *server; + char buf[4096]; + apr_size_t bsize = sizeof(buf); + const char *ip, *val; + + apr_brigade_cleanup(tmpbb); + + if (APR_BRIGADE_EMPTY(bb)) { + break; + } + + rv = apr_brigade_split_line(tmpbb, bb, + APR_BLOCK_READ, sizeof(buf)); + lineno++; + + if (rv) { + return rv; + } + + apr_brigade_flatten(tmpbb, buf, &bsize); + + if (bsize == 0) { + break; + } + + buf[bsize - 1] = 0; + + /* comment */ + if (buf[0] == '#') { + continue; + } + + /* line format: <IP> <query_string>\n */ + t = strchr(buf, ' '); + if (!t) { + continue; + } + + ip = apr_pstrmemdup(pool, buf, t - buf); + t++; + + server = apr_hash_get(servers, ip, APR_HASH_KEY_STRING); + + if (server == NULL) { + server = apr_pcalloc(pool, sizeof(hb_server_t)); + server->ip = ip; + server->port = 80; + server->seen = -1; + + apr_hash_set(servers, server->ip, APR_HASH_KEY_STRING, server); + } + + apr_table_clear(hbt); + + argstr_to_table(pool, apr_pstrdup(pool, t), hbt); + + if ((val = apr_table_get(hbt, "busy"))) { + server->busy = atoi(val); + } + + if ((val = apr_table_get(hbt, "ready"))) { + server->ready = atoi(val); + } + + if ((val = apr_table_get(hbt, "lastseen"))) { + server->seen = atoi(val); + } + + if ((val = apr_table_get(hbt, "port"))) { + server->port = atoi(val); + } + + if (server->busy == 0 && server->ready != 0) { + /* Server has zero threads active, but lots of them ready, + * it likely just started up, so lets /4 the number ready, + * to prevent us from completely flooding it with all new + * requests. + */ + server->ready = server->ready / 4; + } + + } while (1); + } + + return APR_SUCCESS; +} + +static apr_status_t hm_read(void* mem, void *data, apr_pool_t *pool) +{ + hm_slot_server_t *slotserver = (hm_slot_server_t *) mem; + ctx_servers_t *ctx = (ctx_servers_t *) data; + apr_hash_t *servers = (apr_hash_t *) ctx->servers; + hb_server_t *server = apr_hash_get(servers, slotserver->ip, APR_HASH_KEY_STRING); + if (server == NULL) { + server = apr_pcalloc(pool, sizeof(hb_server_t)); + server->ip = apr_pstrdup(pool, slotserver->ip); + server->seen = -1; + + apr_hash_set(servers, server->ip, APR_HASH_KEY_STRING, server); + + } + server->busy = slotserver->busy; + server->ready = slotserver->ready; + server->seen = apr_time_sec(ctx->now - slotserver->seen); + server->id = slotserver->id; + if (server->busy == 0 && server->ready != 0) { + server->ready = server->ready / 4; + } + return APR_SUCCESS; +} +static apr_status_t readslot_heartbeats(ctx_servers_t *ctx, + apr_pool_t *pool) +{ + storage->doall(hm_serversmem, hm_read, ctx, pool); + return APR_SUCCESS; +} + + +static apr_status_t read_heartbeats(const char *path, apr_hash_t *servers, + apr_pool_t *pool) +{ + apr_status_t rv; + if (hm_serversmem) { + ctx_servers_t ctx; + ctx.now = apr_time_now(); + ctx.servers = servers; + rv = readslot_heartbeats(&ctx, pool); + } else + rv = readfile_heartbeats(path, servers, pool); + return rv; +} + +static proxy_worker *find_best_hb(proxy_balancer *balancer, + request_rec *r) +{ + apr_status_t rv; + int i; + apr_uint32_t openslots = 0; + proxy_worker **worker; + hb_server_t *server; + apr_array_header_t *up_servers; + proxy_worker *mycandidate = NULL; + apr_pool_t *tpool; + apr_hash_t *servers; + + lb_hb_ctx_t *ctx = + ap_get_module_config(r->server->module_config, + &lbmethod_heartbeat_module); + + ap_proxy_retry_worker_fn = + APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker); + if (!ap_proxy_retry_worker_fn) { + /* can only happen if mod_proxy isn't loaded */ + return NULL; + } + + apr_pool_create(&tpool, r->pool); + apr_pool_tag(tpool, "lb_heartbeat_tpool"); + + servers = apr_hash_make(tpool); + + rv = read_heartbeats(ctx->path, servers, tpool); + + if (rv) { + ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01213) + "lb_heartbeat: Unable to read heartbeats at '%s'", + ctx->path); + apr_pool_destroy(tpool); + return NULL; + } + + up_servers = apr_array_make(tpool, apr_hash_count(servers), sizeof(hb_server_t *)); + + for (i = 0; i < balancer->workers->nelts; i++) { + worker = &APR_ARRAY_IDX(balancer->workers, i, proxy_worker *); + server = apr_hash_get(servers, (*worker)->s->hostname_ex, APR_HASH_KEY_STRING); + + if (!server) { + ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(01214) + "lb_heartbeat: No server for worker %s", (*worker)->s->name_ex); + continue; + } + + if (!PROXY_WORKER_IS_USABLE(*worker)) { + ap_proxy_retry_worker_fn("BALANCER", *worker, r->server); + } + + if (PROXY_WORKER_IS_USABLE(*worker)) { + server->worker = *worker; + if (server->seen < LBM_HEARTBEAT_MAX_LASTSEEN) { + openslots += server->ready; + APR_ARRAY_PUSH(up_servers, hb_server_t *) = server; + } + } + } + + if (openslots > 0) { + apr_uint32_t c = 0; + apr_uint32_t pick = 0; + + pick = ap_random_pick(0, openslots); + + for (i = 0; i < up_servers->nelts; i++) { + server = APR_ARRAY_IDX(up_servers, i, hb_server_t *); + if (pick >= c && pick <= c + server->ready) { + mycandidate = server->worker; + } + + c += server->ready; + } + } + + apr_pool_destroy(tpool); + + return mycandidate; +} + +static apr_status_t reset(proxy_balancer *balancer, server_rec *s) +{ + return APR_SUCCESS; +} + +static apr_status_t age(proxy_balancer *balancer, server_rec *s) +{ + return APR_SUCCESS; +} + +static const proxy_balancer_method heartbeat = +{ + "heartbeat", + &find_best_hb, + NULL, + &reset, + &age, + NULL +}; + +static int lb_hb_init(apr_pool_t *p, apr_pool_t *plog, + apr_pool_t *ptemp, server_rec *s) +{ + apr_size_t size; + unsigned int num; + lb_hb_ctx_t *ctx = ap_get_module_config(s->module_config, + &lbmethod_heartbeat_module); + + /* do nothing on first call */ + if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG) + return OK; + + storage = ap_lookup_provider(AP_SLOTMEM_PROVIDER_GROUP, "shm", + AP_SLOTMEM_PROVIDER_VERSION); + if (!storage) { + ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, s, APLOGNO(02281) + "Failed to lookup provider 'shm' for '%s'. Maybe you " + "need to load mod_slotmem_shm?", + AP_SLOTMEM_PROVIDER_GROUP); + return OK; + } + + /* Try to use a slotmem created by mod_heartmonitor */ + storage->attach(&hm_serversmem, "mod_heartmonitor", &size, &num, p); + if (!hm_serversmem) + ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, s, APLOGNO(02282) + "No slotmem from mod_heartmonitor"); + else + ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, s, APLOGNO(02283) + "Using slotmem from mod_heartmonitor"); + + if (hm_serversmem) + ctx->path = "(slotmem)"; + + return OK; +} + +static void register_hooks(apr_pool_t *p) +{ + static const char * const aszPred[]={ "mod_heartmonitor.c", NULL }; + ap_register_provider(p, PROXY_LBMETHOD, "heartbeat", "0", &heartbeat); + ap_hook_post_config(lb_hb_init, aszPred, NULL, APR_HOOK_MIDDLE); +} + +static void *lb_hb_create_config(apr_pool_t *p, server_rec *s) +{ + lb_hb_ctx_t *ctx = (lb_hb_ctx_t *) apr_palloc(p, sizeof(lb_hb_ctx_t)); + + ctx->path = ap_runtime_dir_relative(p, DEFAULT_HEARTBEAT_STORAGE); + + return ctx; +} + +static void *lb_hb_merge_config(apr_pool_t *p, void *basev, void *overridesv) +{ + lb_hb_ctx_t *ps = apr_pcalloc(p, sizeof(lb_hb_ctx_t)); + lb_hb_ctx_t *base = (lb_hb_ctx_t *) basev; + lb_hb_ctx_t *overrides = (lb_hb_ctx_t *) overridesv; + + if (overrides->path) { + ps->path = apr_pstrdup(p, overrides->path); + } + else { + ps->path = apr_pstrdup(p, base->path); + } + + return ps; +} + +static const char *cmd_lb_hb_storage(cmd_parms *cmd, + void *dconf, const char *path) +{ + apr_pool_t *p = cmd->pool; + lb_hb_ctx_t *ctx = + (lb_hb_ctx_t *) ap_get_module_config(cmd->server->module_config, + &lbmethod_heartbeat_module); + + const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY); + + if (err != NULL) { + return err; + } + + ctx->path = ap_runtime_dir_relative(p, path); + + return NULL; +} + +static const command_rec cmds[] = { + AP_INIT_TAKE1("HeartbeatStorage", cmd_lb_hb_storage, NULL, RSRC_CONF, + "Path to read heartbeat data."), + {NULL} +}; + +AP_DECLARE_MODULE(lbmethod_heartbeat) = { + STANDARD20_MODULE_STUFF, + NULL, /* create per-directory config structure */ + NULL, /* merge per-directory config structures */ + lb_hb_create_config, /* create per-server config structure */ + lb_hb_merge_config, /* merge per-server config structures */ + cmds, /* command apr_table_t */ + register_hooks /* register hooks */ +}; |