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escalate plugin: handle origin not reachable #11847

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escalate plugin: handle origin not reachable #11847

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102 changes: 65 additions & 37 deletions plugins/escalate/escalate.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,9 @@
#include <iterator>
#include <map>

#include "swoc/IPEndpoint.h"
#include "swoc/TextView.h"

// Constants and some declarations

const char PLUGIN_NAME[] = "escalate";
Expand Down Expand Up @@ -72,12 +75,19 @@ struct EscalationState {
char *
MakeEscalateUrl(TSMBuffer mbuf, TSMLoc url, const char *host, size_t host_len, int &url_len)
{
char *url_str = nullptr;

swoc::TextView input_host_view{host, host_len};
std::string_view host_view;
std::string_view port_view;
swoc::IPEndpoint::tokenize(input_host_view, &host_view, &port_view);
// Update the request URL with the new Host to try.
TSUrlHostSet(mbuf, url, host, host_len);
url_str = TSUrlStringGet(mbuf, url, &url_len);
Dbg(dbg_ctl, "Setting new URL to %.*s", url_len, url_str);
TSUrlHostSet(mbuf, url, host_view.data(), host_view.size());
if (port_view.size()) {
int const port_int = swoc::svtou(port_view);
TSUrlPortSet(mbuf, url, port_int);
Dbg(dbg_ctl, "Setting port to %d", port_int);
}
char *url_str = TSUrlStringGet(mbuf, url, &url_len);
Dbg(dbg_ctl, "Setting new URL from configured %.*s to %.*s", (int)host_len, host, url_len, url_str);

return url_str;
}
Expand All @@ -88,67 +98,84 @@ MakeEscalateUrl(TSMBuffer mbuf, TSMLoc url, const char *host, size_t host_len, i
static int
EscalateResponse(TSCont cont, TSEvent event, void *edata)
{
TSHttpTxn txn = static_cast<TSHttpTxn>(edata);
EscalationState *es = static_cast<EscalationState *>(TSContDataGet(cont));
EscalationState::StatusMapType::const_iterator entry;
TSMBuffer mbuf;
TSMLoc hdrp, url;
TSHttpStatus status;
char *url_str = nullptr;
int url_len, tries;

TSAssert(event == TS_EVENT_HTTP_READ_RESPONSE_HDR);

// First, we need the server response ...
if (TS_SUCCESS != TSHttpTxnServerRespGet(txn, &mbuf, &hdrp)) {
goto no_action;
TSHttpTxn txn = static_cast<TSHttpTxn>(edata);
EscalationState *es = static_cast<EscalationState *>(TSContDataGet(cont));
TSMBuffer mbuf;
TSMLoc hdrp, url;

TSAssert(event == TS_EVENT_HTTP_READ_RESPONSE_HDR || event == TS_EVENT_HTTP_SEND_RESPONSE_HDR);
bool const processing_connection_error = (event == TS_EVENT_HTTP_SEND_RESPONSE_HDR);

if (processing_connection_error) {
TSServerState const state = TSHttpTxnServerStateGet(txn);
if (state == TS_SRVSTATE_CONNECTION_ALIVE) {
// There is no connection error, so nothing to do.
TSHttpTxnReenable(txn, TS_EVENT_HTTP_CONTINUE);
return TS_EVENT_NONE;
}
}

tries = TSHttpTxnRedirectRetries(txn);
int const tries = TSHttpTxnRedirectRetries(txn);
if (0 != tries) { // ToDo: Future support for more than one retry-URL
goto no_action;
Dbg(dbg_ctl, "Not pursuing failover due previous redirect already, num tries: %d", tries);
TSHttpTxnReenable(txn, TS_EVENT_HTTP_CONTINUE);
return TS_EVENT_NONE;
}

int ret = 0;
if (processing_connection_error) {
ret = TSHttpTxnClientRespGet(txn, &mbuf, &hdrp);
} else {
ret = TSHttpTxnServerRespGet(txn, &mbuf, &hdrp);
}
if (TS_SUCCESS != ret) {
TSHttpTxnReenable(txn, TS_EVENT_HTTP_CONTINUE);
return TS_EVENT_NONE;
}
Dbg(dbg_ctl, "This is try %d, proceeding", tries);

// Next, the response status ...
status = TSHttpHdrStatusGet(mbuf, hdrp);
TSHandleMLocRelease(mbuf, TS_NULL_MLOC, hdrp); // Don't need this any more
TSHttpStatus const status = TSHttpHdrStatusGet(mbuf, hdrp);
TSHandleMLocRelease(mbuf, TS_NULL_MLOC, hdrp);

// See if we have an escalation retry config for this response code
entry = es->status_map.find(static_cast<unsigned>(status));
// See if we have an escalation retry config for this response code.
auto const entry = es->status_map.find(status);
if (entry == es->status_map.end()) {
goto no_action;
TSHttpTxnReenable(txn, TS_EVENT_HTTP_CONTINUE);
return TS_EVENT_NONE;
}

Dbg(dbg_ctl, "Found an entry for HTTP status %u", static_cast<unsigned>(status));
if (EscalationState::RETRY_URL == entry->second.type) {
url_str = TSstrdup(entry->second.target.c_str());
url_len = entry->second.target.size();
EscalationState::RetryInfo const &retry_info = entry->second;

Dbg(dbg_ctl, "Handling failover redirect for HTTP status %d", status);
char const *url_str = nullptr;
int url_len = 0;
if (EscalationState::RETRY_URL == retry_info.type) {
url_str = TSstrdup(retry_info.target.c_str());
url_len = retry_info.target.size();
Dbg(dbg_ctl, "Setting new URL to %.*s", url_len, url_str);
} else if (EscalationState::RETRY_HOST == entry->second.type) {
} else if (EscalationState::RETRY_HOST == retry_info.type) {
if (es->use_pristine) {
if (TS_SUCCESS == TSHttpTxnPristineUrlGet(txn, &mbuf, &url)) {
url_str = MakeEscalateUrl(mbuf, url, entry->second.target.c_str(), entry->second.target.size(), url_len);
url_str = MakeEscalateUrl(mbuf, url, retry_info.target.c_str(), retry_info.target.size(), url_len);
TSHandleMLocRelease(mbuf, TS_NULL_MLOC, url);
}
} else {
if (TS_SUCCESS == TSHttpTxnClientReqGet(txn, &mbuf, &hdrp)) {
if (TS_SUCCESS == TSHttpHdrUrlGet(mbuf, hdrp, &url)) {
url_str = MakeEscalateUrl(mbuf, url, entry->second.target.c_str(), entry->second.target.size(), url_len);
url_str = MakeEscalateUrl(mbuf, url, retry_info.target.c_str(), retry_info.target.size(), url_len);
}
// Release the request MLoc
TSHandleMLocRelease(mbuf, TS_NULL_MLOC, hdrp);
}
}
Dbg(dbg_ctl, "Setting host URL to %.*s", url_len, url_str);
}

// Now update the Redirect URL, if set
if (url_str) {
TSHttpTxnRedirectUrlSet(txn, url_str, url_len); // Transfers ownership
}

// Set the transaction free ...
no_action:
// Set the transaction free ...
TSHttpTxnReenable(txn, TS_EVENT_HTTP_CONTINUE);
return TS_EVENT_NONE;
}
Expand Down Expand Up @@ -229,5 +256,6 @@ TSRemapDoRemap(void *instance, TSHttpTxn txn, TSRemapRequestInfo * /* rri */)
EscalationState *es = static_cast<EscalationState *>(instance);

TSHttpTxnHookAdd(txn, TS_HTTP_READ_RESPONSE_HDR_HOOK, es->cont);
TSHttpTxnHookAdd(txn, TS_HTTP_SEND_RESPONSE_HDR_HOOK, es->cont);
return TSREMAP_NO_REMAP;
}
130 changes: 130 additions & 0 deletions tests/gold_tests/pluginTest/escalate/escalate.test.py
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,130 @@
'''
'''
# 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.

import os
from ports import get_port

Test.Summary = '''
Test the escalate plugin.
'''

Test.SkipUnless(Condition.PluginExists('escalate.so'))


class EscalateTest:
"""
Test the escalate plugin.
"""

_replay_original_file: str = 'escalate_original.replay.yaml'
_replay_failover_file: str = 'escalate_failover.replay.yaml'

def __init__(self):
'''Configure the test run.'''
tr = Test.AddTestRun('Test escalate plugin.')
self._setup_dns(tr)
self._setup_servers(tr)
self._setup_ts(tr)
self._setup_client(tr)

def _setup_dns(self, tr: 'Process') -> None:
'''Set up the DNS server.

:param tr: The test run to add the DNS server to.
'''
self._dns = tr.MakeDNServer(f"dns", default='127.0.0.1')

def _setup_servers(self, tr: 'Process') -> None:
'''Set up the origin and failover servers.

:param tr: The test run to add the servers to.
'''
tr.Setup.Copy(self._replay_original_file)
tr.Setup.Copy(self._replay_failover_file)
self._server_origin = tr.AddVerifierServerProcess(f"server_origin", self._replay_original_file)
self._server_failover = tr.AddVerifierServerProcess(f"server_failover", self._replay_failover_file)

self._server_origin.Streams.All += Testers.ContainsExpression(
'uuid: GET', "Verify the origin server received the GET request.")
self._server_origin.Streams.All += Testers.ContainsExpression(
'uuid: GET_chunked', "Verify the origin server GET request for chunked content.")
self._server_origin.Streams.All += Testers.ContainsExpression(
'uuid: GET_failed', "Verify the origin server received the GET request that it returns a 502 with.")
self._server_origin.Streams.All += Testers.ExcludesExpression(
'uuid: GET_down_origin', "Verify the origin server did not receive the down origin request.")

self._server_failover.Streams.All += Testers.ContainsExpression(
'uuid: GET_failed', "Verify the failover server received the failed GET request.")
self._server_failover.Streams.All += Testers.ContainsExpression(
'uuid: GET_down_origin', "Verify the failover server received the GET request for the down origin.")

self._server_failover.Streams.All += Testers.ExcludesExpression(
'x-request: first', "Verify the failover server did not receive the GET request.")
self._server_failover.Streams.All += Testers.ExcludesExpression(
'uuid: GET_chunked', "Verify the failover server did not receive the GET request for chunked content.")

def _setup_ts(self, tr: 'Process') -> None:
'''Set up Traffic Server.

:param tr: The test run to add Traffic Server to.
'''
self._ts = tr.MakeATSProcess(f"ts", enable_cache=False)
# Select a port that is guaranteed to not be used at the moment.
dead_port = get_port(self._ts, "dead_port")
self._ts.Disk.records_config.update(
{
'proxy.config.diags.debug.enabled': 1,
'proxy.config.diags.debug.tags': 'http|escalate',
'proxy.config.dns.nameservers': f'127.0.0.1:{self._dns.Variables.Port}',
'proxy.config.dns.resolv_conf': 'NULL',
'proxy.config.http.redirect.actions': 'self:follow',
'proxy.config.http.number_of_redirections': 4,
})
self._ts.Disk.remap_config.AddLines(
[
f'map http://origin.server.com http://backend.origin.server.com:{self._server_origin.Variables.http_port} '
f'@plugin=escalate.so @pparam=500,502:failover.server.com:{self._server_failover.Variables.http_port}',

# Now create remap entries for the multiplexed hosts: one that
# verifies HTTP, and another that verifies HTTPS.
f'map http://down_origin.server.com http://backend.down_origin.server.com:{dead_port} '
f'@plugin=escalate.so @pparam=500,502:failover.server.com:{self._server_failover.Variables.http_port} ',
])

def _setup_client(self, tr: 'Process') -> None:
'''Set up the client.

:param tr: The test run to add the client to.
'''
client = tr.AddVerifierClientProcess(f"client", self._replay_original_file, http_ports=[self._ts.Variables.port])
client.StartBefore(self._dns)
client.StartBefore(self._server_origin)
client.StartBefore(self._server_failover)
client.StartBefore(self._ts)

client.Streams.All += Testers.ExcludesExpression(r'\[ERROR\]', 'Verify there were no errors in the replay.')
client.Streams.All += Testers.ExcludesExpression('400 Bad', 'Verify none of the 400 responses make it to the client.')
client.Streams.All += Testers.ExcludesExpression('502 Bad', 'Verify none of the 502 responses make it to the client.')
client.Streams.All += Testers.ExcludesExpression('500 Internal', 'Verify none of the 500 responses make it to the client.')
client.Streams.All += Testers.ContainsExpression('x-response: first', 'Verify that the first response was received.')
client.Streams.All += Testers.ContainsExpression('x-response: second', 'Verify that the second response was received.')
client.Streams.All += Testers.ContainsExpression('x-response: third', 'Verify that the third response was received.')
client.Streams.All += Testers.ContainsExpression('x-response: fourth', 'Verify that the fourth response was received.')


EscalateTest()
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