RAII objhits.cc
ActivePublic
Actions

Authored by CDanis on Nov 28 2018, 4:29 PM.

Tags

None

Referenced Files

	F27322241: RAII objhits.cc
	Nov 28 2018, 4:35 PM

	F27322224: RAII objhits.cc
	Nov 28 2018, 4:29 PM

Subscribers

None

	/*
	* Copyright 2018 Emanuele Rocca <ema@wikimedia.org>
	*
	* Licensed 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 <unordered_map>
	#include <iostream>
	#include <cstring>

	#include "ts/ts.h"

	static const char *PLUGIN_NAME = "objhits";
	static const char *HEADER_NAME = "X-ObjHits";

	typedef std::unordered_map<std::string, int> ObjMap;

	char *
	get_request_url(TSHttpTxn txnp) {
	char *url = nullptr;
	int url_len = 0;
	TSMBuffer request;
	TSMLoc req_hdr;

	// All this to get the request URL in url...
	if (TS_SUCCESS == TSHttpTxnClientReqGet(txnp, &request, &req_hdr)) {
	TSMLoc c_url = TS_NULL_MLOC;

	if (TS_SUCCESS == TSUrlCreate(request, &c_url)) {
	if (TS_SUCCESS == TSHttpTxnCacheLookupUrlGet(txnp, request, c_url)) {
	url = TSUrlStringGet(request, c_url, &url_len);
	TSHandleMLocRelease(request, TS_NULL_MLOC, c_url);
	}
	}
	TSHandleMLocRelease(request, TS_NULL_MLOC, req_hdr);
	}

	if (!url) {
	// This should not happen
	TSError("[%s]: Couldn't get URL", PLUGIN_NAME);
	}

	return url;
	}

	void
	handle_response(TSHttpTxn txnp, TSCont contp) {
	char *url = get_request_url(txnp);
	ObjMap m = static_cast<ObjMap >(TSContDataGet(contp));

	// The marshal buffer containing the HTTP response
	TSMBuffer resp_bufp = nullptr;
	// TSMLoc location pointer for the HTTP header
	TSMLoc http_hdr_loc = nullptr;
	// TSMLoc location pointers for the MIME field
	TSMLoc new_field_loc = nullptr;

	{
	TSScopedMutexLock l(TSContMutexGet(contp));

	if (m->find(url) == m->end()) {
	// This should not happen
	TSError("[%s]: No objhits for %s", PLUGIN_NAME, url);
	goto cleanup;
	}

	if (TSHttpTxnClientRespGet(txnp, &resp_bufp, &http_hdr_loc) != TS_SUCCESS) {
	TSError("[%s]: Could not retrieve response", PLUGIN_NAME);
	goto cleanup;
	}

	if (TSMimeHdrFieldCreate(resp_bufp, http_hdr_loc, &new_field_loc) != TS_SUCCESS) {
	TSError("[%s]: Could not create header field", PLUGIN_NAME);
	goto cleanup;
	}

	// Set header name
	if (TSMimeHdrFieldNameSet(resp_bufp, http_hdr_loc, new_field_loc, HEADER_NAME, strlen(HEADER_NAME)) != TS_SUCCESS) {
	TSError("[%s]: Could not set header name", PLUGIN_NAME);
	goto cleanup;
	}

	// Set header Value
	if (TSMimeHdrFieldValueUintInsert(resp_bufp, http_hdr_loc, new_field_loc, -1, m->at(url)) != TS_SUCCESS) {
	TSError("[%s]: Could not set field value", PLUGIN_NAME);
	goto cleanup;
	}

	if (TSMimeHdrFieldAppend(resp_bufp, http_hdr_loc, new_field_loc) != TS_SUCCESS) {
	TSError("[%s]: Could not append field", PLUGIN_NAME);
	goto cleanup;
	}
	}

	cleanup:
	if (resp_bufp) {
	TSHandleMLocRelease(resp_bufp, http_hdr_loc, new_field_loc);
	TSHandleMLocRelease(resp_bufp, TS_NULL_MLOC, http_hdr_loc);
	}

	TSfree(url);

	// Reenable and continue with the state machine
	TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
	}

	static void
	handle_cache_lookup(TSHttpTxn txnp, TSCont contp)
	{
	int obj_status;
	ObjMap m = static_cast<ObjMap >(TSContDataGet(contp));

	if (TSHttpTxnIsInternal(txnp)) {
	// Should we skip internal Traffic Server transactions? What are those
	// exactly?
	TSError("[%s]: TSHttpTxnIsInternal", PLUGIN_NAME);
	goto done;
	}

	if (TSHttpTxnCacheLookupStatusGet(txnp, &obj_status) == TS_ERROR) {
	TSError("[%s]: TSHttpTxnCacheLookupStatusGet", PLUGIN_NAME);
	goto done;
	}

	if (obj_status == TS_CACHE_LOOKUP_HIT_FRESH) {
	// Increment cache hit counter for this transaction
	char *url = get_request_url(txnp);


	{
	TSScopedMutexLock l(TSContMutexGet(contp));

	if (m->find(url) == m->end()) {
	m->insert({url, 1});
	} else {
	m->insert({url, ++m->at(url)});
	}
	}

	TSfree(url);

	// Get back to us whenever TS_EVENT_HTTP_SEND_RESPONSE_HDR happens
	// Note that TSHttpTxnHookAdd != TSHttpHookAdd
	TSHttpTxnHookAdd(txnp, TS_HTTP_SEND_RESPONSE_HDR_HOOK, contp);
	}

	done:
	// Reenable and continue with the state machine
	TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
	}

	static int
	objhits_plugin(TSCont contp, TSEvent event, void *edata)
	{
	TSHttpTxn txnp = static_cast<TSHttpTxn>(edata);

	switch (event) {
	case TS_EVENT_HTTP_CACHE_LOOKUP_COMPLETE:
	handle_cache_lookup(txnp, contp);
	return 0;

	case TS_EVENT_HTTP_SEND_RESPONSE_HDR:
	handle_response(txnp, contp);
	return 0;
	default:
	TSDebug(PLUGIN_NAME, "Unhandled event %d", (int)event);
	break;
	}

	return 0;
	}

	void
	TSPluginInit(int argc, const char *argv[])
	{
	TSPluginRegistrationInfo info;
	info.plugin_name = PLUGIN_NAME;
	info.vendor_name = (char *)"Emanuele Rocca";
	info.support_email = (char *)"ema@wikimedia.org";

	if (TSPluginRegister(&info) != TS_SUCCESS) {
	TSError("%s failed to register", PLUGIN_NAME);
	exit(-1);
	}

	TSDebug(PLUGIN_NAME, "loaded");

	ObjMap *m = new ObjMap;

	TSCont contp = TSContCreate(objhits_plugin, TSMutexCreate());
	TSContDataSet(contp, static_cast<void *>(m));

	TSHttpHookAdd(TS_HTTP_CACHE_LOOKUP_COMPLETE_HOOK, contp);
	}

Event Timeline

CDanis created this paste.Nov 28 2018, 4:29 PM

CDanis edited the content of this paste. (Show Details)Nov 28 2018, 4:35 PM

Tarrow mentioned this in T253552: Detailed Reports from game DB.May 25 2020, 11:41 AM

Bugreporter mentioned this in T378189: PropertySuggester suggests deleted property.Oct 25 2024, 2:43 PM

karapayneWMDE mentioned this in T377986: Q4 2024 update of Property Suggester data.Nov 20 2024, 10:09 AM

RAII objhits.ccActivePublicActions

Event Timeline

RAII objhits.cc
ActivePublic
Actions