[
https://issues.apache.org/jira/browse/TS-4723?focusedWorklogId=26893&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-26893
]
ASF GitHub Bot logged work on TS-4723:
--------------------------------------
Author: ASF GitHub Bot
Created on: 23/Aug/16 12:20
Start Date: 23/Aug/16 12:20
Worklog Time Spent: 10m
Work Description: Github user SolidWallOfCode commented on a diff in the
pull request:
https://github.com/apache/trafficserver/pull/843#discussion_r75853615
--- Diff: plugins/experimental/carp/carp.cc ---
@@ -0,0 +1,713 @@
+/** @file
+
+ A brief file description
+
+ @section license License
+
+ 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 <errno.h>
+
+#include <string>
+#include <sstream>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <memory.h>
+
+#include <ts/ts.h>
+
+#include "Common.h"
+#include "CarpConfig.h"
+#include "CarpConfigPool.h"
+#include "CarpHashAlgorithm.h"
+#include "UrlComponents.h"
+
+using namespace std;
+
+CarpConfigPool* g_CarpConfigPool = NULL;
+int g_carpSelectedHostArgIndex = 0;
+TSTextLogObject g_logObject = NULL;
+
+const char *logFileName = "carp";
+
+//////////////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////////
+/*
+ check for our carp routed header, dump status if requested
+ */
+static int
+processCarpRoutedHeader(TSHttpTxn txnp, TSMBuffer bufp, TSMLoc hdr_loc)
+{
+ string value;
+ if (getHeader(bufp, hdr_loc, CARP_ROUTED_HEADER, value)) { // if found
header
+ if (value.compare("1") == 0) { // is loop prevention value
+ TSDebug(DEBUG_TAG_HOOK, "Found %s header with loop prevention value,
not forwarding again", CARP_ROUTED_HEADER.c_str());
+ return 0;
+ } else if (value.compare("dump") == 0) { // is dump status request
+ TSDebug(DEBUG_TAG_HOOK, "Found %s header with dump request",
CARP_ROUTED_HEADER.c_str());
+ string status;
+ g_CarpConfigPool->getGlobalHashAlgo()->dump(status);
+ TSHttpTxnSetHttpRetStatus(txnp, TS_HTTP_STATUS_MULTI_STATUS);
+ TSHttpTxnErrorBodySet(txnp, TSstrdup(status.c_str()),
status.length(), NULL);
+ return -1;
+ }
+ TSDebug(DEBUG_TAG_HOOK, "Found %s header with unknown value of %s,
ignoring", CARP_ROUTED_HEADER.c_str(), value.c_str());
+ removeHeader(bufp, hdr_loc, CARP_ROUTED_HEADER);
+ }
+ return 1; // all OK
+}
+
+static bool
+checkListForSelf(std::vector<HashNode *> list)
+{
+ for (size_t k = 0; k < list.size(); k++) {
+ if (list[k]->isSelf) return true;
+ }
+ return false;
+}
+
+/**
+ bIsPOSTRemap = false --- Hash request and forward to peer
+ bIsPOSTRemap = true --- hash request, extract OS sockaddr, insert
forwarding header, forward
+ */
+static int
+handleRequestProcessing(TSCont contp, TSEvent event, void *edata, bool
bIsPOSTRemap)
+{
+ TSHttpTxn txnp = (TSHttpTxn) edata;
+ TSMBuffer bufp;
+ TSMLoc hdr_loc;
+ TSMLoc url_loc;
+
+ // get the client request so we can get URL and add header
+ if (TSHttpTxnClientReqGet(txnp, &bufp, &hdr_loc) != TS_SUCCESS) {
+ TSError("carp couldn't get request headers");
+ return -1;
+ }
+
+ int method_len;
+ const char *method = TSHttpHdrMethodGet(bufp, hdr_loc, &method_len);
+ if (NULL == method) {
+ TSError("carp couldn't get http method");
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return -1;
+ }
+ if (((method_len == TS_HTTP_LEN_DELETE) && (strncasecmp(method,
TS_HTTP_METHOD_DELETE, TS_HTTP_LEN_DELETE) == 0)) ||
+ ((method_len == TS_HTTP_LEN_PURGE) && (strncasecmp(method,
TS_HTTP_METHOD_PURGE, TS_HTTP_LEN_PURGE) == 0))) {
+ TSDebug(DEBUG_TAG_HOOK, "Request method is '%s' so not routing
request", string(method,method_len).c_str());
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return 0;
+ }
+
+ if (TSHttpHdrUrlGet(bufp, hdr_loc, &url_loc) != TS_SUCCESS) {
+ TSError("carp couldn't get url");
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return -1;
+ }
+ // if has carp loop prevention header, do not remap
+ int iTemp = processCarpRoutedHeader(txnp, bufp, hdr_loc);
+ if(iTemp <= 0) { // if dump or do not remap
+ // check origin client request's scheme for premap mode
+ if (!bIsPOSTRemap) {
+ string oriScheme;
+ if (!getHeader(bufp, hdr_loc, CARP_PREMAP_SCHEME, oriScheme)) {
+ TSDebug(DEBUG_TAG_HOOK, "couldn't get '%s' header",
CARP_PREMAP_SCHEME.c_str());
+ } else {
+ bool isHttps = (oriScheme == TS_URL_SCHEME_HTTPS);
+
+ if (isHttps) {
+ TSUrlSchemeSet(bufp, url_loc, TS_URL_SCHEME_HTTPS,
TS_URL_LEN_HTTPS);
+ } else {
+ TSUrlSchemeSet(bufp, url_loc, TS_URL_SCHEME_HTTP,
TS_URL_LEN_HTTP);
+ }
+
+ removeHeader(bufp, hdr_loc, CARP_STATUS_HEADER);
+ removeHeader(bufp, hdr_loc, CARP_ROUTED_HEADER);
+ removeHeader(bufp, hdr_loc, CARP_PREMAP_SCHEME.c_str());
+ TSDebug(DEBUG_TAG_HOOK, "Set client request's scheme to %s through
%s header",
+ isHttps?"https":"http", CARP_PREMAP_SCHEME.c_str());
+ }
+ } else {
+ removeHeader(bufp, hdr_loc, CARP_ROUTED_HEADER);
+ }
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return iTemp;
+ }
+
+ UrlComponents reqUrl;
+ reqUrl.populate(bufp, url_loc);
+ // the url ONLY used to determine the cache owner
+ string sUrl;
+
+ if (!bIsPOSTRemap) { // if pre-remap, then host not in URL so get from
header
+ string sHost;
+ if (!getHeader(bufp, hdr_loc, TS_MIME_FIELD_HOST, sHost)) {
+ TSDebug(DEBUG_TAG_HOOK, "Could not find host header, ignoring it");
+ }
+ reqUrl.setHost(sHost);
--- End diff --
Shouldn't this be in `else` if it's being ignored?
Issue Time Tracking
-------------------
Worklog Id: (was: 26893)
Time Spent: 4h 20m (was: 4h 10m)
> ATS CARP Plugin
> ---------------
>
> Key: TS-4723
> URL: https://issues.apache.org/jira/browse/TS-4723
> Project: Traffic Server
> Issue Type: New Feature
> Components: Plugins
> Reporter: Eric Schwartz
> Assignee: Eric Schwartz
> Fix For: 7.0.0
>
> Time Spent: 4h 20m
> Remaining Estimate: 0h
>
> Open sourcing this plugin we use internally within Yahoo in place of
> hierarchical caching.
> CARP is a plugin that allows you to group a bunch of ATS hosts into a cluster
> and share cache space across the entire group. This is done with consistent
> hashing on the object URL to generate an "owner" node in the cluster.
> Requests to any other node in the cluster will be forwarded on to the
> corresponding owner. More info in the README.
> Difference from internal version of note:
> I've ripped out some code we weren't entirely sure we could open source
> because of a hash function. If it turns out that we can open source this,
> I'll do so. The CarpHashAlgorithm class is meant to be extensible, so any
> consistent hash function can replace it. The function included here is pretty
> straightforward but not what we use in production, so just wanted to use that
> caveat.
> One last caveat:
> You'll see some code and documentation in here for object replication. This
> is something I added recently to CARP that allows you to specify an object be
> replicated a certain number of times in the cluster. This is useful if you
> have a network partition or if you're performing some sort of update. When an
> object's primary owner is unreachable, a node in the cluster can go to the
> secondary owner if it's available rather than having to fall all the way back
> to origin. While I've done some initial testing on this with my own cluster
> of hosts, it's not been tested in production so use at your own risk for now.
> I'll be sure to keep the open source community informed on the progress of
> our tests with this feature.
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