MEDIUM: cache: store objects in cache
Store object in the cache. The cache use an shctx for storage.
It uses an http-response action to store the headers and a filter to
store the body. The http-response action is used in order to allow
modifications by other actions before caching.
diff --git a/src/cache.c b/src/cache.c
index 7159a52..7ff7cec 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -10,7 +10,6 @@
* 2 of the License, or (at your option) any later version.
*/
-
#include <eb32tree.h>
#include <proto/channel.h>
@@ -35,6 +34,8 @@
static const char *cache_store_flt_id = "cache store filter";
+static struct pool_head *pool2_cache_st = NULL;
+
struct applet http_cache_applet;
struct flt_ops cache_ops;
@@ -67,12 +68,275 @@
static struct list caches = LIST_HEAD_INIT(caches);
static struct cache *tmp_cache_config = NULL;
+struct cache_entry *entry_exist(struct cache *cache, struct cache_entry *new_entry)
+{
+ struct eb32_node *node;
+ struct cache_entry *entry;
+
+ node = eb32_lookup(&cache->entries, new_entry->eb.key);
+ if (!node)
+ return NULL;
+
+ entry = eb32_entry(node, struct cache_entry, eb);
+ if (entry->expire > now.tv_sec)
+ return entry;
+ else
+ eb32_delete(node);
+ return NULL;
+
+}
+
+static inline struct shared_context *shctx_ptr(struct cache *cache)
+{
+ return (struct shared_context *)((unsigned char *)cache - ((struct shared_context *)NULL)->data);
+}
+
static int
cache_store_init(struct proxy *px, struct flt_conf *f1conf)
{
return 0;
}
+static int
+cache_store_chn_start_analyze(struct stream *s, struct filter *filter, struct channel *chn)
+{
+ if (!(chn->flags & CF_ISRESP))
+ return 1;
+
+ if (filter->ctx == NULL) {
+ struct cache_st *st;
+
+ st = pool_alloc_dirty(pool2_cache_st);
+ if (st == NULL)
+ return -1;
+
+ st->hdrs_len = 0;
+ st->first_block = NULL;
+ filter->ctx = st;
+ }
+
+ register_data_filter(s, chn, filter);
+
+ return 1;
+}
+
+static int
+cache_store_http_headers(struct stream *s, struct filter *filter, struct http_msg *msg)
+{
+ struct cache_st *st = filter->ctx;
+
+ /* end of headers, exclude the final \r\n allow to forward the final
+ * \r\n in the data filter */
+ if (!(msg->chn->flags & CF_ISRESP) || !st)
+ return 1;
+
+ st->hdrs_len = msg->eoh;
+
+ return 1;
+}
+
+static int
+cache_store_http_forward_data(struct stream *s, struct filter *filter,
+ struct http_msg *msg, unsigned int len)
+{
+ struct cache_st *st = filter->ctx;
+ struct shared_context *shctx = shctx_ptr((struct cache *)filter->config->conf);
+ int ret;
+
+ /*
+ * We need to skip the HTTP headers first, because we saved them in the
+ * http-response action.
+ */
+ if (!(msg->chn->flags & CF_ISRESP) || !st)
+ return len;
+
+ if (!len) {
+ /* Nothing to foward */
+ ret = len;
+ }
+ else if (st->hdrs_len > len) {
+ /* Forward part of headers */
+ ret = len;
+ st->hdrs_len -= len;
+ }
+ else if (st->hdrs_len > 0) {
+ /* Forward remaining headers */
+ ret = st->hdrs_len;
+ st->hdrs_len = 0;
+ }
+ else {
+ /* Forward trailers data */
+ if (len) {
+ if (filter->ctx && st->first_block) {
+ /* disable buffering if too much data (never greater than a buffer size */
+ if (len > global.tune.bufsize - global.tune.maxrewrite - st->first_block->len) {
+ filter->ctx = NULL; /* disable cache */
+ shctx_lock(shctx);
+ shctx_row_dec_hot(shctx, st->first_block);
+ shctx_unlock(shctx);
+ pool_free2(pool2_cache_st, st);
+ ret = 0;
+ } else {
+
+ int blen;
+ blen = shctx_row_data_append(shctx,
+ st->first_block,
+ (unsigned char *)bi_ptr(msg->chn->buf),
+ MIN(bi_contig_data(msg->chn->buf), len));
+
+ ret = MIN(bi_contig_data(msg->chn->buf), len) + blen;
+ }
+ } else {
+ ret = len;
+ }
+ }
+ }
+
+ if ((ret != len) ||
+ (FLT_NXT(filter, msg->chn) != FLT_FWD(filter, msg->chn) + ret))
+ task_wakeup(s->task, TASK_WOKEN_MSG);
+
+ return ret;
+}
+
+static int
+cache_store_http_end(struct stream *s, struct filter *filter,
+ struct http_msg *msg)
+{
+ struct cache_st *st = filter->ctx;
+ struct cache *cache = filter->config->conf;
+ struct shared_context *shctx = shctx_ptr(cache);
+ struct cache_entry *object;
+
+ if (!(msg->chn->flags & CF_ISRESP))
+ return 1;
+
+ if (st && st->first_block) {
+
+ object = (struct cache_entry *)st->first_block->data;
+
+ /* does not need to test if the insertion worked, if it
+ * doesn't, the blocks will be reused anyway */
+
+ shctx_lock(shctx);
+ eb32_insert(&cache->entries, &object->eb);
+ shctx_unlock(shctx);
+
+ /* remove from the hotlist */
+ shctx_lock(shctx);
+ shctx_row_dec_hot(shctx, st->first_block);
+ shctx_unlock(shctx);
+
+ }
+ if (st) {
+ pool_free2(pool2_cache_st, st);
+ filter->ctx = NULL;
+ }
+
+ return 1;
+}
+
+ /*
+ * This intends to be used when checking HTTP headers for some
+ * word=value directive. Return a pointer to the first character of value, if
+ * the word was not found or if there wasn't any value assigned ot it return NULL
+ */
+char *directive_value(const char *sample, int slen, const char *word, int wlen)
+{
+ int st = 0;
+
+ if (slen < wlen)
+ return 0;
+
+ while (wlen) {
+ char c = *sample ^ *word;
+ if (c && c != ('A' ^ 'a'))
+ return NULL;
+ sample++;
+ word++;
+ slen--;
+ wlen--;
+ }
+
+ while (slen) {
+ if (st == 0) {
+ if (*sample != '=')
+ return NULL;
+ sample++;
+ slen--;
+ st = 1;
+ continue;
+ } else {
+ return (char *)sample;
+ }
+ }
+
+ return NULL;
+}
+
+/*
+ * Return the maxage in seconds of an HTTP response.
+ * Compute the maxage using either:
+ * - the assigned max-age of the cache
+ * - the s-maxage directive
+ * - the max-age directive
+ * - (Expires - Data) headers
+ * - the default-max-age of the cache
+ *
+ */
+int http_calc_maxage(struct stream *s)
+{
+ struct http_txn *txn = s->txn;
+ struct hdr_ctx ctx;
+
+ int smaxage = -1;
+ int maxage = -1;
+
+
+ /* TODO: forced maxage configuration */
+
+ ctx.idx = 0;
+
+ /* loop on the Cache-Control values */
+ while (http_find_header2("Cache-Control", 13, s->res.buf->p, &txn->hdr_idx, &ctx)) {
+ char *directive = ctx.line + ctx.val;
+ char *value;
+
+ value = directive_value(directive, ctx.vlen, "s-maxage", 8);
+ if (value) {
+ struct chunk *chk = get_trash_chunk();
+
+ chunk_strncat(chk, value, ctx.vlen - 8 + 1);
+ chunk_strncat(chk, "", 1);
+ maxage = atoi(chk->str);
+ }
+
+ value = directive_value(ctx.line + ctx.val, ctx.vlen, "max-age", 7);
+ if (value) {
+ struct chunk *chk = get_trash_chunk();
+
+ chunk_strncat(chk, value, ctx.vlen - 7 + 1);
+ chunk_strncat(chk, "", 1);
+ smaxage = atoi(chk->str);
+ }
+ }
+
+ /* TODO: Expires - Data */
+
+
+ if (smaxage > 0)
+ return smaxage;
+
+ if (maxage > 0)
+ return maxage;
+
+ /* TODO: return default value */
+
+ return 60;
+
+}
+
+
/*
* This fonction will store the headers of the response in a buffer and then
* register a filter to store the data
@@ -80,6 +344,116 @@
enum act_return http_action_store_cache(struct act_rule *rule, struct proxy *px,
struct session *sess, struct stream *s, int flags)
{
+ struct http_txn *txn = s->txn;
+ struct http_msg *msg = &txn->rsp;
+ struct filter *filter;
+ struct hdr_ctx ctx;
+ struct shared_block *first = NULL;
+ struct shared_context *shctx = shctx_ptr((struct cache *)rule->arg.act.p[0]);
+ struct cache_entry *object;
+
+
+ /* Don't cache if the response came from a cache */
+ if ((obj_type(s->target) == OBJ_TYPE_APPLET) &&
+ s->target == &http_cache_applet.obj_type) {
+ goto out;
+ }
+
+ /* cache only HTTP/1.1 */
+ if (!(txn->req.flags & HTTP_MSGF_VER_11))
+ goto out;
+
+ /* cache only GET method */
+ if (txn->meth != HTTP_METH_GET)
+ goto out;
+
+ /* cache only 200 status code */
+ if (txn->status != 200)
+ goto out;
+
+ /* Does not manage Vary at the moment. We will need a secondary key later for that */
+ ctx.idx = 0;
+ if (http_find_header2("Vary", 4, txn->rsp.chn->buf->p, &txn->hdr_idx, &ctx))
+ goto out;
+
+ /* we need to put this flag before using check_response_for_cacheability */
+ txn->flags |= TX_CACHEABLE;
+
+ if (txn->status != 101)
+ check_response_for_cacheability(s, &s->res);
+
+ if (!(txn->flags & TX_CACHEABLE))
+ goto out;
+
+ if ((msg->eoh + msg->body_len) > (global.tune.bufsize - global.tune.maxrewrite))
+ goto out;
+
+ shctx_lock(shctx);
+
+ first = shctx_row_reserve_hot(shctx, sizeof(struct cache_entry) + msg->eoh + msg->body_len);
+ if (!first) {
+ shctx_unlock(shctx);
+ goto out;
+ }
+ shctx_unlock(shctx);
+
+ /* reserve space for the cache_entry structure */
+ first->len = sizeof(struct cache_entry);
+
+ /* cache the headers in a http action because it allows to chose what
+ * to cache, for example you might want to cache a response before
+ * modifying some HTTP headers, or on the contrary after modifying
+ * those headers.
+ */
+
+ /* does not need to be locked because it's in the "hot" list,
+ * copy the headers */
+ if (shctx_row_data_append(shctx, first, (unsigned char *)s->res.buf->p, msg->eoh) < 0)
+ goto out;
+
+ /* register the buffer in the filter ctx for filling it with data*/
+ if (!LIST_ISEMPTY(&s->strm_flt.filters)) {
+ list_for_each_entry(filter, &s->strm_flt.filters, list) {
+ if (filter->config->id == cache_store_flt_id &&
+ filter->config->conf == rule->arg.act.p[0]) {
+ if (filter->ctx) {
+ struct cache_st *cache_ctx = filter->ctx;
+
+ cache_ctx->first_block = first;
+ object = (struct cache_entry *)first->data;
+
+ object->eb.key = hash_djb2(txn->uri, strlen(txn->uri));
+ /* Insert the node later on caching success */
+
+ shctx_lock(shctx);
+ if (entry_exist((struct cache *)rule->arg.act.p[0], object)) {
+ shctx_unlock(shctx);
+ if (filter->ctx) {
+ pool_free2(pool2_cache_st, filter->ctx);
+ filter->ctx = NULL;
+ }
+ goto out;
+ }
+ shctx_unlock(shctx);
+
+ /* store latest value and expiration time */
+ object->latest_validation = now.tv_sec;
+ object->expire = now.tv_sec + http_calc_maxage(s);
+
+ }
+ return ACT_RET_CONT;
+ }
+ }
+ }
+
+out:
+ /* if does not cache */
+ if (first) {
+ shctx_lock(shctx);
+ shctx_row_dec_hot(shctx, first);
+ shctx_unlock(shctx);
+ }
+
return ACT_RET_CONT;
}
@@ -244,6 +618,7 @@
}
ret_shctx = shctx_init(&shctx, tmp_cache_config->maxblocks, CACHE_BLOCKSIZE, sizeof(struct cache), 1);
+
if (ret_shctx < 0) {
if (ret_shctx == SHCTX_E_INIT_LOCK)
Alert("Unable to initialize the lock for the cache.\n");
@@ -253,10 +628,10 @@
err_code |= ERR_FATAL | ERR_ALERT;
goto out;
}
+
memcpy(shctx->data, tmp_cache_config, sizeof(struct cache));
cache = (struct cache *)shctx->data;
cache->entries = EB_ROOT_UNIQUE;
-
LIST_ADDQ(&caches, &cache->list);
}
out:
@@ -359,6 +734,15 @@
struct flt_ops cache_ops = {
.init = cache_store_init,
+ /* Handle channels activity */
+ .channel_start_analyze = cache_store_chn_start_analyze,
+
+ /* Filter HTTP requests and responses */
+ .http_headers = cache_store_http_headers,
+ .http_end = cache_store_http_end,
+
+ .http_forward_data = cache_store_http_forward_data,
+
};
static struct action_kw_list http_res_actions = {
@@ -389,5 +773,6 @@
cfg_register_postparser("cache", cfg_cache_postparser);
http_res_keywords_register(&http_res_actions);
http_req_keywords_register(&http_req_actions);
+ pool2_cache_st = create_pool("cache_st", sizeof(struct cache_st), MEM_F_SHARED);
}