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/*
* Copyright 2018-present Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 "aws/lambda-runtime/runtime.h"
#include "aws/lambda-runtime/version.h"
#include "aws/lambda-runtime/outcome.h"
#include "aws/logging/logging.h"
#include "aws/http/response.h"
#include <curl/curl.h>
#include <curl/curlver.h>
#include <climits> // for ULONG_MAX
#include <cassert>
#include <chrono>
#include <array>
#include <cstdlib> // for strtoul
#define AWS_LAMBDA_RUNTIME_API __attribute__((visibility("default")))
namespace aws {
namespace lambda_runtime {
static char const LOG_TAG[] = "LAMBDA_RUNTIME";
static char const REQUEST_ID_HEADER[] = "lambda-runtime-aws-request-id";
static char const TRACE_ID_HEADER[] = "lambda-runtime-trace-id";
static char const CLIENT_CONTEXT_HEADER[] = "lambda-runtime-client-context";
static char const COGNITO_IDENTITY_HEADER[] = "lambda-runtime-cognito-identity";
static char const DEADLINE_MS_HEADER[] = "lambda-runtime-deadline-ms";
static char const FUNCTION_ARN_HEADER[] = "lambda-runtime-invoked-function-arn";
enum Endpoints {
INIT,
NEXT,
RESULT,
};
static bool is_success(aws::http::response_code httpcode)
{
auto const code = static_cast<int>(httpcode);
return code >= 200 && code <= 299;
}
static size_t write_data(char* ptr, size_t size, size_t nmemb, void* userdata)
{
if (!ptr) {
return 0;
}
auto const resp = static_cast<http::response*>(userdata);
assert(size == 1);
(void)size; // avoid warning in release builds
assert(resp);
resp->append_body(ptr, nmemb);
return nmemb;
}
static inline bool IsSpace(int ch)
{
if (ch < -1 || ch > 255) {
return false;
}
return ::isspace(ch) != 0;
}
static inline std::string trim(std::string s)
{
// trim right
s.erase(std::find_if(s.rbegin(), s.rend(), [](int ch) { return !IsSpace(ch); }).base(), s.end());
// trim left
s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](int ch) { return !IsSpace(ch); }));
return s;
}
static size_t write_header(char* ptr, size_t size, size_t nmemb, void* userdata)
{
if (!ptr) {
return 0;
}
logging::log_debug(LOG_TAG, "received header: %s", std::string(ptr, nmemb).c_str());
auto const resp = static_cast<http::response*>(userdata);
assert(resp);
for (size_t i = 0; i < nmemb; i++) {
if (ptr[i] != ':') {
continue;
}
std::string key{ptr, i};
std::string value{ptr + i + 1, nmemb - i - 1};
resp->add_header(trim(key), trim(value));
break;
}
return size * nmemb;
}
static std::string const& get_user_agent_header()
{
static std::string user_agent = std::string("User-Agent: AWS_Lambda_Cpp/") + get_version();
return user_agent;
}
static size_t read_data(char* buffer, size_t size, size_t nitems, void* userdata)
{
auto const limit = size * nitems;
auto ctx = static_cast<std::pair<std::string const&, size_t>*>(userdata);
assert(ctx);
auto const unread = ctx->first.length() - ctx->second;
if (0 == unread) {
return 0;
}
if (unread <= limit) {
std::copy_n(ctx->first.begin() + ctx->second, unread, buffer);
ctx->second += unread;
return unread;
}
std::copy_n(ctx->first.begin() + ctx->second, limit, buffer);
ctx->second += limit;
return limit;
}
#ifndef NDEBUG
static int rt_curl_debug_callback(CURL* handle, curl_infotype type, char* data, size_t size, void* userdata)
{
(void)handle;
(void)type;
(void)userdata;
std::string s(data, size);
logging::log_debug(LOG_TAG, "CURL DBG: %s", s.c_str());
return 0;
}
#endif
struct no_result {
};
class runtime {
public:
using next_outcome = aws::lambda_runtime::outcome<invocation_request, aws::http::response_code>;
using post_outcome = aws::lambda_runtime::outcome<no_result, aws::http::response_code>;
runtime(std::string const& endpoint);
~runtime();
/**
* Ask lambda for an invocation.
*/
next_outcome get_next();
/**
* Tells lambda that the function has succeeded.
*/
post_outcome post_success(std::string const& request_id, invocation_response const& handler_response);
/**
* Tells lambda that the function has failed.
*/
post_outcome post_failure(std::string const& request_id, invocation_response const& handler_response);
private:
void set_curl_next_options();
void set_curl_post_result_options();
post_outcome do_post(
std::string const& url,
std::string const& request_id,
invocation_response const& handler_response);
private:
std::array<std::string const, 3> const m_endpoints;
CURL* const m_curl_handle;
};
runtime::runtime(std::string const& endpoint)
: m_endpoints{{endpoint + "/2018-06-01/runtime/init/error",
endpoint + "/2018-06-01/runtime/invocation/next",
endpoint + "/2018-06-01/runtime/invocation/"}},
m_curl_handle(curl_easy_init())
{
if (!m_curl_handle) {
logging::log_error(LOG_TAG, "Failed to acquire curl easy handle for next.");
}
}
runtime::~runtime()
{
curl_easy_cleanup(m_curl_handle);
}
void runtime::set_curl_next_options()
{
// lambda freezes the container when no further tasks are available. The freezing period could be longer than the
// request timeout, which causes the following get_next request to fail with a timeout error.
curl_easy_reset(m_curl_handle);
curl_easy_setopt(m_curl_handle, CURLOPT_TIMEOUT, 0L);
curl_easy_setopt(m_curl_handle, CURLOPT_CONNECTTIMEOUT, 1L);
curl_easy_setopt(m_curl_handle, CURLOPT_NOSIGNAL, 1L);
curl_easy_setopt(m_curl_handle, CURLOPT_TCP_NODELAY, 1L);
curl_easy_setopt(m_curl_handle, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
curl_easy_setopt(m_curl_handle, CURLOPT_HTTPGET, 1L);
curl_easy_setopt(m_curl_handle, CURLOPT_URL, m_endpoints[Endpoints::NEXT].c_str());
curl_easy_setopt(m_curl_handle, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(m_curl_handle, CURLOPT_HEADERFUNCTION, write_header);
#ifndef NDEBUG
curl_easy_setopt(m_curl_handle, CURLOPT_VERBOSE, 1);
curl_easy_setopt(m_curl_handle, CURLOPT_DEBUGFUNCTION, rt_curl_debug_callback);
#endif
}
void runtime::set_curl_post_result_options()
{
curl_easy_reset(m_curl_handle);
curl_easy_setopt(m_curl_handle, CURLOPT_TIMEOUT, 0L);
curl_easy_setopt(m_curl_handle, CURLOPT_CONNECTTIMEOUT, 1L);
curl_easy_setopt(m_curl_handle, CURLOPT_NOSIGNAL, 1L);
curl_easy_setopt(m_curl_handle, CURLOPT_TCP_NODELAY, 1L);
curl_easy_setopt(m_curl_handle, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
curl_easy_setopt(m_curl_handle, CURLOPT_POST, 1L);
curl_easy_setopt(m_curl_handle, CURLOPT_READFUNCTION, read_data);
curl_easy_setopt(m_curl_handle, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(m_curl_handle, CURLOPT_HEADERFUNCTION, write_header);
#ifndef NDEBUG
curl_easy_setopt(m_curl_handle, CURLOPT_VERBOSE, 1);
curl_easy_setopt(m_curl_handle, CURLOPT_DEBUGFUNCTION, rt_curl_debug_callback);
#endif
}
runtime::next_outcome runtime::get_next()
{
http::response resp;
set_curl_next_options();
curl_easy_setopt(m_curl_handle, CURLOPT_WRITEDATA, &resp);
curl_easy_setopt(m_curl_handle, CURLOPT_HEADERDATA, &resp);
curl_slist* headers = nullptr;
headers = curl_slist_append(headers, get_user_agent_header().c_str());
logging::log_debug(LOG_TAG, "Making request to %s", m_endpoints[Endpoints::NEXT].c_str());
CURLcode curl_code = curl_easy_perform(m_curl_handle);
logging::log_debug(LOG_TAG, "Completed request to %s", m_endpoints[Endpoints::NEXT].c_str());
curl_slist_free_all(headers);
if (curl_code != CURLE_OK) {
logging::log_debug(LOG_TAG, "CURL returned error code %d - %s", curl_code, curl_easy_strerror(curl_code));
logging::log_error(LOG_TAG, "Failed to get next invocation. No Response from endpoint");
return aws::http::response_code::REQUEST_NOT_MADE;
}
{
long resp_code;
curl_easy_getinfo(m_curl_handle, CURLINFO_RESPONSE_CODE, &resp_code);
resp.set_response_code(static_cast<aws::http::response_code>(resp_code));
}
{
char* content_type = nullptr;
curl_easy_getinfo(m_curl_handle, CURLINFO_CONTENT_TYPE, &content_type);
resp.set_content_type(content_type);
}
if (!is_success(resp.get_response_code())) {
logging::log_error(
LOG_TAG,
"Failed to get next invocation. Http Response code: %d",
static_cast<int>(resp.get_response_code()));
return resp.get_response_code();
}
if (!resp.has_header(REQUEST_ID_HEADER)) {
logging::log_error(LOG_TAG, "Failed to find header %s in response", REQUEST_ID_HEADER);
return aws::http::response_code::REQUEST_NOT_MADE;
}
invocation_request req;
req.payload = resp.get_body();
req.request_id = resp.get_header(REQUEST_ID_HEADER);
if (resp.has_header(TRACE_ID_HEADER)) {
req.xray_trace_id = resp.get_header(TRACE_ID_HEADER);
}
if (resp.has_header(CLIENT_CONTEXT_HEADER)) {
req.client_context = resp.get_header(CLIENT_CONTEXT_HEADER);
}
if (resp.has_header(COGNITO_IDENTITY_HEADER)) {
req.cognito_identity = resp.get_header(COGNITO_IDENTITY_HEADER);
}
if (resp.has_header(FUNCTION_ARN_HEADER)) {
req.function_arn = resp.get_header(FUNCTION_ARN_HEADER);
}
if (resp.has_header(DEADLINE_MS_HEADER)) {
auto const& deadline_string = resp.get_header(DEADLINE_MS_HEADER);
unsigned long ms = strtoul(deadline_string.c_str(), nullptr, 10);
assert(ms > 0);
assert(ms < ULONG_MAX);
req.deadline += std::chrono::milliseconds(ms);
logging::log_info(
LOG_TAG,
"Received payload: %s\nTime remaining: %ld",
req.payload.c_str(),
req.get_time_remaining().count());
}
return next_outcome(req);
}
runtime::post_outcome runtime::post_success(std::string const& request_id, invocation_response const& handler_response)
{
std::string const url = m_endpoints[Endpoints::RESULT] + request_id + "/response";
return do_post(url, request_id, handler_response);
}
runtime::post_outcome runtime::post_failure(std::string const& request_id, invocation_response const& handler_response)
{
std::string const url = m_endpoints[Endpoints::RESULT] + request_id + "/error";
return do_post(url, request_id, handler_response);
}
runtime::post_outcome runtime::do_post(
std::string const& url,
std::string const& request_id,
invocation_response const& handler_response)
{
set_curl_post_result_options();
curl_easy_setopt(m_curl_handle, CURLOPT_URL, url.c_str());
logging::log_info(LOG_TAG, "Making request to %s", url.c_str());
curl_slist* headers = nullptr;
if (handler_response.get_content_type().empty()) {
headers = curl_slist_append(headers, "content-type: text/html");
}
else {
headers = curl_slist_append(headers, ("content-type: " + handler_response.get_content_type()).c_str());
}
headers = curl_slist_append(headers, "Expect:");
headers = curl_slist_append(headers, "transfer-encoding:");
headers = curl_slist_append(headers, get_user_agent_header().c_str());
auto const& payload = handler_response.get_payload();
logging::log_debug(
LOG_TAG, "calculating content length... %s", ("content-length: " + std::to_string(payload.length())).c_str());
headers = curl_slist_append(headers, ("content-length: " + std::to_string(payload.length())).c_str());
std::pair<std::string const&, size_t> ctx{payload, 0};
aws::http::response resp;
curl_easy_setopt(m_curl_handle, CURLOPT_WRITEDATA, &resp);
curl_easy_setopt(m_curl_handle, CURLOPT_HEADERDATA, &resp);
curl_easy_setopt(m_curl_handle, CURLOPT_READDATA, &ctx);
curl_easy_setopt(m_curl_handle, CURLOPT_HTTPHEADER, headers);
CURLcode curl_code = curl_easy_perform(m_curl_handle);
curl_slist_free_all(headers);
if (curl_code != CURLE_OK) {
logging::log_debug(
LOG_TAG,
"CURL returned error code %d - %s, for invocation %s",
curl_code,
curl_easy_strerror(curl_code),
request_id.c_str());
return aws::http::response_code::REQUEST_NOT_MADE;
}
long http_response_code;
curl_easy_getinfo(m_curl_handle, CURLINFO_RESPONSE_CODE, &http_response_code);
if (!is_success(aws::http::response_code(http_response_code))) {
logging::log_error(
LOG_TAG, "Failed to post handler success response. Http response code: %ld.", http_response_code);
return aws::http::response_code(http_response_code);
}
return post_outcome(no_result{});
}
static bool handle_post_outcome(runtime::post_outcome const& o, std::string const& request_id)
{
if (o.is_success()) {
return true;
}
if (o.get_failure() == aws::http::response_code::REQUEST_NOT_MADE) {
logging::log_error(LOG_TAG, "Failed to send HTTP request for invocation %s.", request_id.c_str());
return false;
}
logging::log_info(
LOG_TAG,
"HTTP Request for invocation %s was not successful. HTTP response code: %d.",
request_id.c_str(),
static_cast<int>(o.get_failure()));
return false;
}
AWS_LAMBDA_RUNTIME_API
void run_handler(std::function<invocation_response(invocation_request const&)> const& handler)
{
logging::log_info(LOG_TAG, "Initializing the C++ Lambda Runtime.");
std::string endpoint("http://");
if (auto ep = std::getenv("AWS_LAMBDA_RUNTIME_API")) {
assert(ep);
logging::log_debug(LOG_TAG, "LAMBDA_SERVER_ADDRESS defined in environment as: %s", ep);
endpoint += ep;
}
runtime rt(endpoint);
size_t retries = 0;
size_t const max_retries = 3;
while (retries < max_retries) {
const auto next_outcome = rt.get_next();
if (!next_outcome.is_success()) {
if (next_outcome.get_failure() == aws::http::response_code::REQUEST_NOT_MADE) {
++retries;
continue;
}
logging::log_info(
LOG_TAG,
"HTTP request was not successful. HTTP response code: %d. Retrying..",
static_cast<int>(next_outcome.get_failure()));
++retries;
continue;
}
retries = 0;
auto const& req = next_outcome.get_result();
logging::log_info(LOG_TAG, "Invoking user handler");
invocation_response res = handler(req);
logging::log_info(LOG_TAG, "Invoking user handler completed.");
if (res.is_success()) {
const auto post_outcome = rt.post_success(req.request_id, res);
if (!handle_post_outcome(post_outcome, req.request_id)) {
return; // TODO: implement a better retry strategy
}
}
else {
const auto post_outcome = rt.post_failure(req.request_id, res);
if (!handle_post_outcome(post_outcome, req.request_id)) {
return; // TODO: implement a better retry strategy
}
}
}
if (retries == max_retries) {
logging::log_error(
LOG_TAG, "Exhausted all retries. This is probably a bug in libcurl v" LIBCURL_VERSION " Exiting!");
}
}
static std::string json_escape(std::string const& in)
{
std::string out;
out.reserve(in.length()); // most strings will end up identical
for (char ch : in) {
if (ch > 31 && ch != '\"' && ch != '\\') {
out.append(1, ch);
}
else {
out.append(1, '\\');
switch (ch) {
case '\\':
out.append(1, '\\');
break;
case '"':
out.append(1, '"');
break;
case '\b':
out.append(1, 'b');
break;
case '\f':
out.append(1, 'f');
break;
case '\n':
out.append(1, 'n');
break;
case '\r':
out.append(1, 'r');
break;
case '\t':
out.append(1, 't');
break;
default:
// escape and print as unicode codepoint
char buf[6]; // 4 hex + letter 'u' + \0
sprintf(buf, "u%04x", ch);
out.append(buf, 5); // add only five, discarding the null terminator.
break;
}
}
}
return out;
}
AWS_LAMBDA_RUNTIME_API
invocation_response invocation_response::success(std::string const& payload, std::string const& content_type)
{
invocation_response r;
r.m_success = true;
r.m_content_type = content_type;
r.m_payload = payload;
return r;
}
AWS_LAMBDA_RUNTIME_API
invocation_response invocation_response::failure(std::string const& error_message, std::string const& error_type)
{
invocation_response r;
r.m_success = false;
r.m_content_type = "application/json";
r.m_payload = R"({"errorMessage":")" + json_escape(error_message) + R"(","errorType":")" + json_escape(error_type) +
R"(", "stackTrace":[]})";
return r;
}
} // namespace lambda_runtime
} // namespace aws
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