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add MISS capability to the regex_revalidate plugin #7899

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Merged
traeak merged 1 commit into from
May 28, 2021
Merged

add MISS capability to the regex_revalidate plugin #7899

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15 changes: 14 additions & 1 deletion doc/admin-guide/plugins/regex_revalidate.en.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,7 @@ Inside your revalidation rules configuration, each rule line is defined as a
regular expression followed by an integer which expresses the epoch time at
which the rule will expire::

<regular expression> <rule expiry, as seconds since epoch>
<regular expression> <rule expiry, as seconds since epoch> [type MISS or default STALE]

Blank lines and lines beginning with a ``#`` character are ignored.

Expand All @@ -97,6 +97,16 @@ expressed as an integer of seconds since epoch (equivalent to the return value
of :manpage:`time(2)`), after which the forced revalidation will no longer
occur.

Type
----

By default any matching asset will have its cache lookup status changed
from HIT_FRESH to HIT_STALE. By adding an extra keyword MISS at the end
of a line the asset will be marked MISS instead, forcing a refetch from
the parent. *Use with care* as this will increase bandwidth to the parent.
During configuration reload, any rule which changes it type will be
reloaded and treated as a new rule.

Caveats
=======

Expand Down Expand Up @@ -128,3 +138,6 @@ in |TS| until 6:47:27 AM on Saturday, November 14th, 2015 (UTC)::

Note the escaping of the ``.`` metacharacter in the rule's regular expression.

Alternatively the following rule would case a refetch from the parent::

http://origin\.tld/images/foo\.jpg 1447483647 MISS
59 changes: 50 additions & 9 deletions plugins/regex_revalidate/regex_revalidate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -45,12 +45,33 @@
#define LOG_ROLL_INTERVAL 86400
#define LOG_ROLL_OFFSET 0

static char const *const RESULT_MISS = "MISS";
static char const *const RESULT_STALE = "STALE";
static char const *const RESULT_UNKNOWN = "UNKNOWN";

static char const *const
strForResult(TSCacheLookupResult const result)
{
switch (result) {
case TS_CACHE_LOOKUP_MISS:
return RESULT_MISS;
break;
case TS_CACHE_LOOKUP_HIT_STALE:
return RESULT_STALE;
break;
default:
return RESULT_UNKNOWN;
break;
}
}

typedef struct invalidate_t {
const char *regex_text;
pcre *regex;
pcre_extra *regex_extra;
time_t epoch;
time_t expiry;
TSCacheLookupResult new_result;
struct invalidate_t *next;
} invalidate_t;

Expand All @@ -69,6 +90,7 @@ init_invalidate_t(invalidate_t *i)
i->regex_extra = NULL;
i->epoch = 0;
i->expiry = 0;
i->new_result = TS_CACHE_LOOKUP_HIT_STALE;
i->next = NULL;
return i;
}
Expand Down Expand Up @@ -139,6 +161,7 @@ copy_invalidate_t(invalidate_t *i)
iptr->regex_extra = pcre_study(iptr->regex, 0, &errptr); // Assuming no errors since this worked before :-/
iptr->epoch = i->epoch;
iptr->expiry = i->expiry;
iptr->new_result = i->new_result;
iptr->next = NULL;
return iptr;
}
Expand Down Expand Up @@ -177,7 +200,8 @@ prune_config(invalidate_t **i)
ilast = NULL;
while (iptr) {
if (difftime(iptr->expiry, now) < 0) {
TSDebug(LOG_PREFIX, "Removing %s expiry: %d now: %d", iptr->regex_text, (int)iptr->expiry, (int)now);
TSDebug(LOG_PREFIX, "Removing %s expiry: %d type: %s now: %d", iptr->regex_text, (int)iptr->expiry,
strForResult(iptr->new_result), (int)now);
if (ilast) {
ilast->next = iptr->next;
free_invalidate_t(iptr);
Expand Down Expand Up @@ -229,18 +253,27 @@ load_config(plugin_state_t *pstate, invalidate_t **ilist)
TSDebug(LOG_PREFIX, "Could not open %s for reading", path);
return false;
}
config_re = pcre_compile("^([^#].+?)\\s+(\\d+)\\s*$", 0, &errptr, &erroffset, NULL);
config_re = pcre_compile("^([^#].+?)\\s+(\\d+)(\\s+(\\w+))?\\s*$", 0, &errptr, &erroffset, NULL);
while (fgets(line, LINE_MAX, fs) != NULL) {
ln++;
TSDebug(LOG_PREFIX, "Processing: %d %s", ln, line);
rc = pcre_exec(config_re, NULL, line, strlen(line), 0, 0, ovector, OVECTOR_SIZE);
if (rc == 3) {
if (3 <= rc) {
i = (invalidate_t *)TSmalloc(sizeof(invalidate_t));
init_invalidate_t(i);
pcre_get_substring(line, ovector, rc, 1, &i->regex_text);
i->epoch = now;
i->expiry = atoi(line + ovector[4]);
i->regex = pcre_compile(i->regex_text, 0, &errptr, &erroffset, NULL);
if (5 == rc) {
char const *const type = line + ovector[8];
if (0 == strncasecmp(type, RESULT_MISS, strlen(RESULT_MISS))) {
TSDebug(LOG_PREFIX, "Regex line set to result type %s: '%s'", RESULT_MISS, i->regex_text);
i->new_result = TS_CACHE_LOOKUP_MISS;
} else if (0 != strncasecmp(type, RESULT_STALE, strlen(RESULT_STALE))) {
TSDebug(LOG_PREFIX, "Unknown regex line result type '%s', using default '%s' '%s'", type, RESULT_STALE, i->regex_text);
}
}
if (i->expiry <= i->epoch) {
TSDebug(LOG_PREFIX, "Rule is already expired!");
free_invalidate_t(i);
Expand All @@ -251,7 +284,8 @@ load_config(plugin_state_t *pstate, invalidate_t **ilist)
i->regex_extra = pcre_study(i->regex, 0, &errptr);
if (!*ilist) {
*ilist = i;
TSDebug(LOG_PREFIX, "Created new list and Loaded %s %d %d", i->regex_text, (int)i->epoch, (int)i->expiry);
TSDebug(LOG_PREFIX, "Created new list and Loaded %s %d %d %s", i->regex_text, (int)i->epoch, (int)i->expiry,
strForResult(i->new_result));
} else {
iptr = *ilist;
while (1) {
Expand All @@ -261,6 +295,11 @@ load_config(plugin_state_t *pstate, invalidate_t **ilist)
iptr->epoch = i->epoch;
iptr->expiry = i->expiry;
}
if (iptr->new_result != i->new_result) {
TSDebug(LOG_PREFIX, "Resetting duplicate due to type change %s", i->regex_text);
iptr->new_result = i->new_result;
iptr->epoch = now;
}
free_invalidate_t(i);
i = NULL;
break;
Expand All @@ -272,7 +311,7 @@ load_config(plugin_state_t *pstate, invalidate_t **ilist)
}
if (i) {
iptr->next = i;
TSDebug(LOG_PREFIX, "Loaded %s %d %d", i->regex_text, (int)i->epoch, (int)i->expiry);
TSDebug(LOG_PREFIX, "Loaded %s %d %d %s", i->regex_text, (int)i->epoch, (int)i->expiry, strForResult(i->new_result));
}
}
}
Expand Down Expand Up @@ -302,9 +341,11 @@ list_config(plugin_state_t *pstate, invalidate_t *i)
if (i) {
iptr = i;
while (iptr) {
TSDebug(LOG_PREFIX, "%s epoch: %d expiry: %d", iptr->regex_text, (int)iptr->epoch, (int)iptr->expiry);
char const *const typestr = strForResult(i->new_result);
TSDebug(LOG_PREFIX, "%s epoch: %d expiry: %d result: %s", iptr->regex_text, (int)iptr->epoch, (int)iptr->expiry, typestr);
if (pstate->log) {
TSTextLogObjectWrite(pstate->log, "%s epoch: %d expiry: %d", iptr->regex_text, (int)iptr->epoch, (int)iptr->expiry);
TSTextLogObjectWrite(pstate->log, "%s epoch: %d expiry: %d result: %s", iptr->regex_text, (int)iptr->epoch,
(int)iptr->expiry, typestr);
}
iptr = iptr->next;
}
Expand Down Expand Up @@ -419,9 +460,9 @@ main_handler(TSCont cont, TSEvent event, void *edata)
url = TSHttpTxnEffectiveUrlStringGet(txn, &url_len);
}
if (pcre_exec(iptr->regex, iptr->regex_extra, url, url_len, 0, 0, NULL, 0) >= 0) {
TSHttpTxnCacheLookupStatusSet(txn, TS_CACHE_LOOKUP_HIT_STALE);
TSHttpTxnCacheLookupStatusSet(txn, iptr->new_result);
TSDebug(LOG_PREFIX, "Forced revalidate - %.*s %s", url_len, url, strForResult(iptr->new_result));
iptr = NULL;
TSDebug(LOG_PREFIX, "Forced revalidate - %.*s", url_len, url);
}
}
if (iptr) {
Expand Down
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