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MXS-2208 Introduce asynchronous GET

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A multi HTTP GET can now be performed so that the caller
drives the polling of results.

This can now be used so that inside a monitor worker, the delays
are handled using delayed calls. Consequently, the monitor worker
event loop can remain responsive even though the Clustrix nodes
are being polled.
This commit is contained in:
Johan Wikman
2018-12-17 15:45:56 +02:00
parent 38a0d6a2df
commit 847f53b21b
3 changed files with 589 additions and 61 deletions
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414
maxutils/maxbase/src/http.cc
View File

@ -14,11 +14,12 @@
#include <maxbase/http.hh>
#include <algorithm>
#include <array>
#include <map>
#include <unordered_map>
#include <utility>
#include <curl/curl.h>
#include <maxbase/assert.h>
#include <maxbase/string.hh>
#include <iostream>
using namespace std;
using std::array;
@ -128,53 +129,6 @@ CURL* get_easy_curl(const std::string& url,
return pCurl;
}
}
namespace maxbase
{
namespace http
{
Result get(const std::string& url, const Config& config)
{
return std::move(get(url, "", "", config));
}
Result get(const std::string& url, const std::string& user, const std::string& password, const Config& config)
{
Result res;
char errbuf[CURL_ERROR_SIZE + 1] = "";
CURL* pCurl = get_easy_curl(url, user, password, config, &res, errbuf);
mxb_assert(pCurl);
if (curl_easy_perform(pCurl) == CURLE_OK)
{
long code = 0; // needs to be a long
curl_easy_getinfo(pCurl, CURLINFO_RESPONSE_CODE, &code);
res.code = code;
}
else
{
res.code = -1;
res.body = errbuf;
}
curl_easy_cleanup(pCurl);
return res;
}
vector<Result> get(const std::vector<std::string>& urls, const Config& config)
{
return get(urls, "", "", config);
}
namespace
{
using Errbuf = array<char, CURL_ERROR_SIZE + 1>;
struct Context
@ -290,6 +244,11 @@ void execute(CURLM* pCurlm,
curl_easy_getinfo(pCurl, CURLINFO_RESPONSE_CODE, &code);
pResult->code = code;
if ((code == 0) && pResult->body.empty())
{
pResult->body = pErrbuf->data();
}
curls.erase(it);
curl_multi_remove_handle(pCurlm, pCurl);
curl_easy_cleanup(pCurl);
@ -356,6 +315,347 @@ vector<Result> get_curlm(CURLM* pCurlm,
return results;
}
class ErrorImp : public Async::Imp
{
public:
ErrorImp()
{
}
Async::status_t status() const
{
return Async::ERROR;
}
Async::status_t perform(long timeout_ms)
{
return Async::ERROR;
}
long wait_no_more_than() const
{
return 0;
}
const std::vector<Result>& results() const
{
return m_results;
}
private:
vector<Result> m_results;
};
class HttpImp : public Async::Imp
{
public:
HttpImp()
: m_pCurlm(curl_multi_init())
, m_status(Async::ERROR)
, m_still_running(0)
, m_wait_no_more_than(0)
{
mxb_assert(m_pCurlm);
if (!m_pCurlm)
{
throw std::bad_alloc();
}
}
~HttpImp()
{
mxb_assert(m_pCurlm);
for (auto& item : m_curls)
{
CURL* pCurl = item.first;
MXB_AT_DEBUG(CURLMcode rv =) curl_multi_remove_handle(m_pCurlm, pCurl);
mxb_assert(rv == CURLM_OK);
curl_easy_cleanup(pCurl);
}
CURLMcode code = curl_multi_cleanup(m_pCurlm);
if (code != CURLM_OK)
{
MXB_ERROR("curl_multi_cleanup() failed: %s", curl_multi_strerror(code));
}
}
bool initialize(const std::vector<std::string>& urls,
const std::string& user, const std::string& password,
const Config& config)
{
mxb_assert(m_status == Async::ERROR);
m_results.reserve(urls.size());
m_errbufs.reserve(urls.size());
size_t i;
for (i = 0; i < urls.size(); ++i)
{
m_results.resize(i + 1);
m_errbufs.resize(i + 1);
CURL* pCurl = get_easy_curl(urls[i], user, password, config, &m_results[i], m_errbufs[i].data());
if (!pCurl || (curl_multi_add_handle(m_pCurlm, pCurl) != CURLM_OK))
{
mxb_assert(!true);
if (pCurl)
{
curl_easy_cleanup(pCurl);
}
m_results.resize(m_results.size() - 1);
break;
}
else
{
m_curls.insert(std::make_pair(pCurl, Context(&m_results[i], &m_errbufs[i])));
}
}
if (m_results.size() == urls.size())
{
CURLMcode rv = curl_multi_perform(m_pCurlm, &m_still_running);
if (rv == CURLM_OK)
{
if (m_still_running == 0)
{
m_status = Async::READY;
m_wait_no_more_than = 0;
}
else
{
update_timeout();
m_status = Async::PENDING;
}
}
else
{
MXB_ERROR("curl_multi_perform() failed: %s", curl_multi_strerror(rv));
m_status = Async::ERROR;
}
}
return m_status != Async::ERROR;
}
Async::status_t status() const override
{
return m_status;
}
Async::status_t perform(long timeout_ms) override
{
switch (m_status)
{
case Async::READY:
break;
case Async::ERROR:
mxb_assert(!true);
break;
default:
{
mxb_assert(m_status == Async::PENDING);
fd_set fdread;
fd_set fdwrite;
fd_set fdexcep;
FD_ZERO(&fdread);
FD_ZERO(&fdwrite);
FD_ZERO(&fdexcep);
int maxfd;
CURLMcode rv_curl = curl_multi_fdset(m_pCurlm, &fdread, &fdwrite, &fdexcep, &maxfd);
if (rv_curl == CURLM_OK)
{
int rv = 0;
if (maxfd != -1)
{
struct timeval timeout = { timeout_ms / 1000, (timeout_ms % 1000) * 1000 };
rv = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
}
switch (rv)
{
case -1:
mxb_assert(!true);
MXB_ERROR("select() failed: %s", mxb_strerror(errno));
m_status = Async::ERROR;
break;
case 0:
default:
rv_curl = curl_multi_perform(m_pCurlm, &m_still_running);
if (rv_curl == CURLM_OK)
{
if (m_still_running == 0)
{
m_status = Async::READY;
}
else
{
update_timeout();
}
}
else
{
MXB_ERROR("curl_multi_perform() failed: %s", curl_multi_strerror(rv_curl));
m_status = Async::ERROR;
}
}
}
if (m_status == Async::READY)
{
mxb_assert(m_still_running == 0);
int nRemaining = 0;
do
{
CURLMsg* pMsg = curl_multi_info_read(m_pCurlm, &nRemaining);
if (pMsg && (pMsg->msg == CURLMSG_DONE))
{
CURL* pCurl = pMsg->easy_handle;
auto it = m_curls.find(pCurl);
mxb_assert(it != m_curls.end());
auto& context = it->second;
Result* pResult = context.pResult;
Errbuf* pErrbuf = context.pErrbuf;
long code;
curl_easy_getinfo(pCurl, CURLINFO_RESPONSE_CODE, &code);
pResult->code = code;
if ((code == 0) && pResult->body.empty())
{
pResult->body = pErrbuf->data();
}
m_curls.erase(it);
curl_multi_remove_handle(m_pCurlm, pCurl);
curl_easy_cleanup(pCurl);
}
}
while (nRemaining != 0);
}
}
}
return m_status;
}
long wait_no_more_than() const
{
return m_wait_no_more_than;
}
const std::vector<Result>& results() const
{
return m_results;
}
private:
void update_timeout()
{
curl_multi_timeout(m_pCurlm, &m_wait_no_more_than);
if (m_wait_no_more_than < 0)
{
// No default value, we'll use 100ms as default.
m_wait_no_more_than = 100;
}
}
private:
CURLM* m_pCurlm;
Async::status_t m_status;
vector<Result> m_results;
vector<array<char, CURL_ERROR_SIZE + 1>> m_errbufs;
unordered_map<CURL*, Context> m_curls;
int m_still_running;
long m_wait_no_more_than;
};
}
namespace maxbase
{
namespace http
{
Async::Imp::~Imp()
{
}
Async::Async()
: m_sImp(std::make_shared<ErrorImp>())
{
}
Async get_async(const std::vector<std::string>& urls,
const Config& config)
{
return get_async(urls, "", "", config);
}
Async get_async(const std::vector<std::string>& urls,
const std::string& user, const std::string& password,
const Config& config)
{
shared_ptr<Async::Imp> sImp;
shared_ptr<HttpImp> sHttp_imp = std::make_shared<HttpImp>();
if (sHttp_imp->initialize(urls, user, password, config))
{
sImp = sHttp_imp;
}
else
{
sImp = std::make_shared<ErrorImp>();
}
return Async(sImp);
}
Result get(const std::string& url, const Config& config)
{
return std::move(get(url, "", "", config));
}
Result get(const std::string& url, const std::string& user, const std::string& password, const Config& config)
{
Result res;
char errbuf[CURL_ERROR_SIZE + 1] = "";
CURL* pCurl = get_easy_curl(url, user, password, config, &res, errbuf);
mxb_assert(pCurl);
if (curl_easy_perform(pCurl) == CURLE_OK)
{
long code = 0; // needs to be a long
curl_easy_getinfo(pCurl, CURLINFO_RESPONSE_CODE, &code);
res.code = code;
}
else
{
res.code = -1;
res.body = errbuf;
}
curl_easy_cleanup(pCurl);
return res;
}
vector<Result> get(const std::vector<std::string>& urls, const Config& config)
{
return get(urls, "", "", config);
}
vector<Result> get(const std::vector<std::string>& urls,
@ -381,6 +681,24 @@ vector<Result> get(const std::vector<std::string>& urls,
return results;
}
const char* to_string(Async::status_t status)
{
switch (status)
{
case Async::READY:
return "READY";
case Async::PENDING:
return "PENDING";
case Async::ERROR:
return "ERROR";
}
mxb_assert(!true);
return "Unknown";
}
}
}