1019656555

Committed 28 Sep 2023 12:42PM UTC coverage: 78.153% (+0.009%) from 78.144%

Build # 1019656555

Build Type

push

gitlab-ci

Committed by

lluiscampos

Commit Message

feat: Implement `mender::update::http_resumer`

Implement class to download the Artifact, which will react to server
disconnections or other sorts of short read by scheduling new HTTP
requests with `Range` header.

See https://developer.mozilla.org/en-US/docs/Web/HTTP/Range_requests for
an introduction to the feature, and read the specification for more
details.

The user calls _once_ `AsyncCall` with the header and body handlers, and
`DownloadResumerClient` will call back these handlers _once_ (each). At
the user's header handler, the Reader returned by `MakeBodyAsyncReader`
is a wrapper of the actual Body reader that is taking care of the resume
of the download, calling the `AsyncRead` finalized handler only after
the download is fully completed (with potential resumes) and or/the
resuming times out.

The validation of the `Content-Range` header and the cases for the unit
tests are heavily inspired by the legacy client. See:
* https://github.com/mendersoftware/mender/blob/<a class=hub.com/mendersoftware/mender/commit/d9010526d35d3ac861ea1e4210d36c2fef748ef8">d9010526d/client/update_resumer.go#L113
* https://github.com/mendersoftware/mender/blob/d9010526d35d3ac861ea1e4210d36c2fef748ef8/client/update_resumer_test.go#L197

Ticket: MEN-6498
Changelog: None

Signed-off-by: Lluis Campos <lluis.campos@northern.tech>

Run Details

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79.15

/mender-update/http_resumer/http_resumer.cpp

// Copyright 2023 Northern.tech AS
//
//    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 <mender-update/http_resumer.hpp>

#include <regex>

#include <common/common.hpp>
#include <common/expected.hpp>

namespace mender {
namespace update {
namespace http_resumer {

namespace common = mender::common;
namespace expected = mender::common::expected;
namespace http = mender::http;

// Represents the parts of a Content-Range HTTP header
// See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Range
struct RangeHeader {
        long long int range_start {0};
        long long int range_end {0};
        long long int size {0};
};
using ExpectedRangeHeader = expected::expected<RangeHeader, error::Error>;

// Parses the HTTP Content-Range header
// For an alternative implementation without regex dependency see:
// https://github.com/mendersoftware/mender/pull/1372/commits/ea711fc4dafa943266e9013fd6704da3d4518a27
ExpectedRangeHeader ParseRangeHeader(string header) {
        RangeHeader range_header {};

        std::regex content_range_regexp {R"(bytes\s+(\d+)\s?-\s?(\d+)\s?\/?\s?(\d+|\*)?)"};

        std::smatch range_matches;
        if (!regex_match(header, range_matches, content_range_regexp)) {
                return expected::unexpected(http::MakeError(
                        http::NoSuchHeaderError, "Invalid Content-Range returned from server: " + header));
        }

        auto exp_range_start = common::StringToLongLong(range_matches[1].str());
        auto exp_range_end = common::StringToLongLong(range_matches[2].str());
        if (!exp_range_start || !exp_range_end) {
                return expected::unexpected(http::MakeError(
                        http::NoSuchHeaderError, "Content-Range contains invalid number: " + header));
        }
        range_header.range_start = exp_range_start.value();
        range_header.range_end = exp_range_end.value();

        if (range_header.range_start > range_header.range_end) {
                return expected::unexpected(http::MakeError(
                        http::NoSuchHeaderError, "Invalid Content-Range returned from server: " + header));
        }

        if ((range_matches[3].matched) && (range_matches[3].str() != "*")) {
                auto exp_size = common::StringToLongLong(range_matches[3].str());
                if (!exp_size) {
                        return expected::unexpected(http::MakeError(
                                http::NoSuchHeaderError, "Content-Range contains invalid number: " + header));
                }
                range_header.size = exp_size.value();
        }

        return range_header;
}

class HeaderHandlerFunctor {
public:
        HeaderHandlerFunctor(weak_ptr<DownloadResumerClient> resumer) :
                resumer_client_ {resumer} {};

        void operator()(http::ExpectedIncomingResponsePtr exp_resp);

private:
        void HandleFirstResponse(
                const shared_ptr<DownloadResumerClient> &resumer_client,
                http::ExpectedIncomingResponsePtr exp_resp);
        void HandleNextResponse(
                const shared_ptr<DownloadResumerClient> &resumer_client,
                http::ExpectedIncomingResponsePtr exp_resp);

        weak_ptr<DownloadResumerClient> resumer_client_;
};

class BodyHandlerFunctor {
public:
        BodyHandlerFunctor(weak_ptr<DownloadResumerClient> resumer) :
                resumer_client_ {resumer} {};

        void operator()(http::ExpectedIncomingResponsePtr exp_resp);

private:
        weak_ptr<DownloadResumerClient> resumer_client_;
};

void HeaderHandlerFunctor::operator()(http::ExpectedIncomingResponsePtr exp_resp) {
        auto resumer_client = resumer_client_.lock();
        if (resumer_client) {
                if (resumer_client->resumer_state_->active_state == DownloadResumerActiveStatus::Resuming) {
                        HandleNextResponse(resumer_client, exp_resp);
                } else {
                        HandleFirstResponse(resumer_client, exp_resp);
                }
        }
}

void HeaderHandlerFunctor::HandleFirstResponse(
        const shared_ptr<DownloadResumerClient> &resumer_client,
        http::ExpectedIncomingResponsePtr exp_resp) {
        // The first response shall always call the user header callback. On resumable responses, we
        // create a our own incoming response and call the user header handler. On errors, we log a
        // warning and call the user handler with the original response

        if (!exp_resp) {
                resumer_client->logger_.Warning(exp_resp.error().String());
                resumer_client->CallUserHandler(exp_resp);
                return;
        }
        auto resp = exp_resp.value();

        if (resp->GetStatusCode() != mender::http::StatusOK) {
                // Non-resumable response
                resumer_client->CallUserHandler(exp_resp);
                return;
        }

        auto exp_header = resp->GetHeader("Content-Length");
        if (!exp_header || exp_header.value() == "0") {
                resumer_client->logger_.Warning("Response does not contain Content-Length header");
                resumer_client->CallUserHandler(exp_resp);
                return;
        }

        auto exp_length = common::StringToLongLong(exp_header.value());
        if (!exp_length || exp_length.value() < 0) {
                resumer_client->logger_.Warning(
                        "Content-Length contains invalid number: " + exp_header.value());
                resumer_client->CallUserHandler(exp_resp);
                return;
        }

        // Resumable response
        resumer_client->resumer_state_->active_state = DownloadResumerActiveStatus::Resuming;
        resumer_client->resumer_state_->offset = 0;
        resumer_client->resumer_state_->content_length = exp_length.value();

        // Prepare a modified response and call user handler
        resumer_client->response_.reset(new http::IncomingResponse(*resumer_client, resp->cancelled_));
        resumer_client->response_->status_code_ = resp->GetStatusCode();
        resumer_client->response_->status_message_ = resp->GetStatusMessage();
        resumer_client->response_->headers_ = resp->GetHeaders();
        resumer_client->CallUserHandler(resumer_client->response_);
}

void HeaderHandlerFunctor::HandleNextResponse(
        const shared_ptr<DownloadResumerClient> &resumer_client,
        http::ExpectedIncomingResponsePtr exp_resp) {
        // If an error occurs has already occurred, schedule the next AsyncCall directly
        // If an error occurs during handling here, cancel the resuming and call the user handler.
        if (!exp_resp) {
                resumer_client->logger_.Warning(exp_resp.error().String());

                auto err = resumer_client->ScheduleNextResumeRequest();
                if (err != error::NoError) {
                        resumer_client->logger_.Error(err.String());
                        resumer_client->Cancel();
                        resumer_client->CallUserHandler(expected::unexpected(err));
                }
                return;
        }
        auto resp = exp_resp.value();

        auto exp_content_range = resp->GetHeader("Content-Range").and_then(ParseRangeHeader);
        if (!exp_content_range) {
                resumer_client->logger_.Error(exp_content_range.error().String());
                resumer_client->Cancel();
                resumer_client->CallUserHandler(expected::unexpected(exp_content_range.error()));
                return;
        }

        auto content_range = exp_content_range.value();
        if (content_range.size != 0
                && content_range.size != resumer_client->resumer_state_->content_length) {
                auto size_changed_err = http::MakeError(
                        http::DownloadResumerError,
                        "Size of artifact changed after download was resumed (expected "
                                + to_string(resumer_client->resumer_state_->content_length) + ", got "
                                + to_string(content_range.size) + ")");
                resumer_client->logger_.Error(size_changed_err.String());
                resumer_client->Cancel();
                resumer_client->CallUserHandler(expected::unexpected(size_changed_err));
                return;
        }

        if ((content_range.range_end != resumer_client->resumer_state_->content_length - 1)
                || (content_range.range_start != resumer_client->resumer_state_->offset)) {
                auto bad_range_err = http::MakeError(
                        http::DownloadResumerError,
                        "HTTP server returned an different range than requested. Requested "
                                + to_string(resumer_client->resumer_state_->offset) + "-"
                                + to_string(resumer_client->resumer_state_->content_length - 1) + ", got "
                                + to_string(content_range.range_start) + "-" + to_string(content_range.range_end));
                resumer_client->logger_.Error(bad_range_err.String());
                resumer_client->Cancel();
                resumer_client->CallUserHandler(expected::unexpected(bad_range_err));
                return;
        }

        // Get the reader for the new response
        auto exp_reader = resumer_client->client_.MakeBodyAsyncReader(resp);
        if (!exp_reader) {
                auto bad_range_err = exp_reader.error().WithContext("cannot get the reader after resume");
                resumer_client->logger_.Error(bad_range_err.String());
                resumer_client->Cancel();
                resumer_client->CallUserHandler(expected::unexpected(bad_range_err));
                return;
        }
        // Update the inner reader of the user reader
        resumer_client->resumer_reader_->inner_reader_ = exp_reader.value();

        // Resume reading reusing last user data (start, end, handler)
        auto err = resumer_client->resumer_reader_->AsyncReadResume();
        if (err != error::NoError) {
                auto bad_read_err = err.WithContext("error reading after resume");
                resumer_client->logger_.Error(bad_read_err.String());
                resumer_client->Cancel();
                resumer_client->CallUserHandler(expected::unexpected(bad_read_err));
                return;
        }
}

void BodyHandlerFunctor::operator()(http::ExpectedIncomingResponsePtr exp_resp) {
        auto resumer_client = resumer_client_.lock();
        if (!resumer_client) {
                return;
        }

        if (*resumer_client->cancelled_) {
                resumer_client->CallUserHandler(exp_resp);
                return;
        }

        if (resumer_client->resumer_state_->active_state == DownloadResumerActiveStatus::Inactive) {
                resumer_client->CallUserHandler(exp_resp);
                return;
        }

        // We resume the download if either:
        // * there is any error or
        // * successful read with status code Partial Content and there is still data missing
        const bool is_range_response =
                exp_resp && exp_resp.value()->GetStatusCode() == mender::http::StatusPartialContent;
        const bool is_data_missing =
                resumer_client->resumer_state_->offset < resumer_client->resumer_state_->content_length;
        if (!exp_resp || (is_range_response && is_data_missing)) {
                if (!exp_resp) {
                        resumer_client->logger_.Info(
                                "Will try to resume after error " + exp_resp.error().String());
                }

                auto err = resumer_client->ScheduleNextResumeRequest();
                if (err != error::NoError) {
                        resumer_client->logger_.Error(err.String());
                        resumer_client->Cancel();
                        resumer_client->CallUserHandler(expected::unexpected(err));
                        return;
                }
        } else {
                // Update headers with the last received server response. When resuming has taken place,
                // the user will get different headers on header and body handlers, representing (somehow)
                // what the resumer has been doing in its behalf.
                auto resp = exp_resp.value();
                resumer_client->response_->status_code_ = resp->GetStatusCode();
                resumer_client->response_->status_message_ = resp->GetStatusMessage();
                resumer_client->response_->headers_ = resp->GetHeaders();

                // Finished, call the user handler \o/
                resumer_client->logger_.Debug("Download resumed and completed successfully");
                resumer_client->DoCancel();
                resumer_client->CallUserHandler(resumer_client->response_);
        }
}

void DownloadResumerAsyncReader::Cancel() {
        if (!*cancelled_) {
                inner_reader_->Cancel();
        }
}

error::Error DownloadResumerAsyncReader::AsyncRead(
        vector<uint8_t>::iterator start, vector<uint8_t>::iterator end, io::AsyncIoHandler handler) {
        auto resumer_client = resumer_client_.lock();
        if (!resumer_client || *cancelled_) {
                return error::MakeError(
                        error::ProgrammingError,
                        "DownloadResumerAsyncReader::AsyncRead called after stream is destroyed");
        }
        // Save user parameters for further resumes of the body read
        resumer_client->last_read_ = {.start = start, .end = end, .handler = handler};
        return AsyncReadResume();
}

error::Error DownloadResumerAsyncReader::AsyncReadResume() {
        auto resumer_client = resumer_client_.lock();
        if (!resumer_client) {
                return error::MakeError(
                        error::ProgrammingError,
                        "DownloadResumerAsyncReader::AsyncReadResume called after client is destroyed");
        }
        return inner_reader_->AsyncRead(
                resumer_client->last_read_.start,
                resumer_client->last_read_.end,
                [this](io::ExpectedSize result) {
                        if (!result) {
                                inner_reader_.reset();

                                logger_.Warning(
                                        "Reading error, a new request will be re-scheduled. "
                                        + result.error().String());
                        } else {
                                resumer_state_->offset += result.value();
                                logger_.Debug("read " + to_string(result.value()) + " bytes");
                                auto resumer_client = resumer_client_.lock();
                                if (resumer_client) {
                                        resumer_client->last_read_.handler(result);
                                } else {
                                        logger_.Error(
                                                "AsyncRead finish handler called after resumer client has been destroyed.");
                                }
                        }
                });
}

DownloadResumerClient::DownloadResumerClient(
        const http::ClientConfig &config, events::EventLoop &event_loop) :
        resumer_state_ {make_shared<DownloadResumerClientState>()},
        client_(config, event_loop, "http_resumer:client"),
        logger_ {"http_resumer:client"},
        cancelled_ {make_shared<bool>(true)},
        retry_ {
                .backoff = http::ExponentialBackoff(chrono::minutes(1), 10),
                .wait_timer = events::Timer(event_loop)} {
}

DownloadResumerClient::~DownloadResumerClient() {
        if (!*cancelled_) {
                logger_.Warning("DownloadResumerClient destroyed while request is still active!");
        }
        client_.Cancel();
}

error::Error DownloadResumerClient::AsyncCall(
        http::OutgoingRequestPtr req,
        http::ResponseHandler user_header_handler,
        http::ResponseHandler user_body_handler) {
        HeaderHandlerFunctor resumer_header_handler {shared_from_this()};
        BodyHandlerFunctor resumer_body_handler {shared_from_this()};

        user_request_ = req;
        user_header_handler_ = user_header_handler;
        user_body_handler_ = user_body_handler;

        if (!*cancelled_) {
                return error::Error(
                        make_error_condition(errc::operation_in_progress), "HTTP call already ongoing");
        }

        *cancelled_ = false;
        retry_.backoff.Reset();
        resumer_state_->active_state = DownloadResumerActiveStatus::Inactive;
        resumer_state_->user_handlers_state = DownloadResumerUserHandlersStatus::None;
        return client_.AsyncCall(req, resumer_header_handler, resumer_body_handler);
}

io::ExpectedAsyncReaderPtr DownloadResumerClient::MakeBodyAsyncReader(
        http::IncomingResponsePtr resp) {
        auto exp_reader = client_.MakeBodyAsyncReader(resp);
        if (!exp_reader) {
                return exp_reader;
        }
        resumer_reader_ = make_shared<DownloadResumerAsyncReader>(
                exp_reader.value(), resumer_state_, cancelled_, shared_from_this());
        return resumer_reader_;
}

http::OutgoingRequestPtr DownloadResumerClient::RemainingRangeRequest() const {
        auto range_req = make_shared<http::OutgoingRequest>(*user_request_);
        range_req->SetHeader(
                "Range",
                "bytes=" + to_string(resumer_state_->offset) + "-"
                        + to_string(resumer_state_->content_length - 1));
        return range_req;
};

error::Error DownloadResumerClient::ScheduleNextResumeRequest() {
        auto exp_interval = retry_.backoff.NextInterval();
        if (!exp_interval) {
                return http::MakeError(
                        http::DownloadResumerError,
                        "Giving up on resuming the download: " + exp_interval.error().String());
        }

        auto interval = exp_interval.value();
        logger_.Info(
                "Resuming download after " + to_string(chrono::milliseconds(interval).count() / 1000)
                + " seconds");

        HeaderHandlerFunctor resumer_next_header_handler {shared_from_this()};
        BodyHandlerFunctor resumer_next_body_handler {shared_from_this()};

        retry_.wait_timer.AsyncWait(
                interval, [this, resumer_next_header_handler, resumer_next_body_handler](error::Error err) {
                        if (err != error::NoError) {
                                auto err_user = http::MakeError(
                                        http::DownloadResumerError, "Unexpected error in wait timer: " + err.String());
                                logger_.Error(err_user.String());
                                Cancel();
                                CallUserHandler(expected::unexpected(err_user));
                                return;
                        }

                        auto next_call_err = client_.AsyncCall(
                                RemainingRangeRequest(), resumer_next_header_handler, resumer_next_body_handler);
                        if (next_call_err != error::NoError) {
                                // Schedule once more
                                auto err = ScheduleNextResumeRequest();
                                if (err != error::NoError) {
                                        logger_.Error(err.String());
                                        Cancel();
                                        CallUserHandler(expected::unexpected(err));
                                }
                        }
                });

        return error::NoError;
}

void DownloadResumerClient::CallUserHandler(http::ExpectedIncomingResponsePtr exp_resp) {
        if (resumer_state_->user_handlers_state == DownloadResumerUserHandlersStatus::None) {
                resumer_state_->user_handlers_state =
                        DownloadResumerUserHandlersStatus::HeaderHandlerCalled;
                user_header_handler_(exp_resp);
        } else if (
                resumer_state_->user_handlers_state
                == DownloadResumerUserHandlersStatus::HeaderHandlerCalled) {
                resumer_state_->user_handlers_state = DownloadResumerUserHandlersStatus::BodyHandlerCalled;
                user_body_handler_(exp_resp);
        } else {
                string msg;
                if (!exp_resp) {
                        msg = "error: " + exp_resp.error().String();
                } else {
                        auto &resp = exp_resp.value();
                        msg = "response: " + to_string(resp->GetStatusCode()) + " " + resp->GetStatusMessage();
                }
                logger_.Warning("Cannot call any user handler with " + msg);
        }
}

void DownloadResumerClient::Cancel() {
        DoCancel();
        client_.Cancel();
};

void DownloadResumerClient::DoCancel() {
        // Set cancel state and then make a new one. Those who are interested should have their own
        // pointer to the old one.
        *cancelled_ = true;
        cancelled_ = make_shared<bool>(true);
};

} // namespace http_resumer
} // namespace update
} // namespace mender

1	// Copyright 2023 Northern.tech AS
2	//
3	// Licensed under the Apache License, Version 2.0 (the "License");
4	// you may not use this file except in compliance with the License.
5	// You may obtain a copy of the License at
6	//
7	// http://www.apache.org/licenses/LICENSE-2.0
8	//
9	// Unless required by applicable law or agreed to in writing, software
10	// distributed under the License is distributed on an "AS IS" BASIS,
11	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12	// See the License for the specific language governing permissions and
13	// limitations under the License.
14
15	#include <mender-update/http_resumer.hpp>
16
17	#include <regex>
18
19	#include <common/common.hpp>
20	#include <common/expected.hpp>
21
22	namespace mender {
23	namespace update {
24	namespace http_resumer {
25
26	namespace common = mender::common;
27	namespace expected = mender::common::expected;
28	namespace http = mender::http;
29
30	// Represents the parts of a Content-Range HTTP header
31	// See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Range
32	struct RangeHeader {
33	long long int range_start {0};
34	long long int range_end {0};
35	long long int size {0};
36	};
37	using ExpectedRangeHeader = expected::expected<RangeHeader, error::Error>;
38
39	// Parses the HTTP Content-Range header
40	// For an alternative implementation without regex dependency see:
41	// https://github.com/mendersoftware/mender/pull/1372/commits/ea711fc4dafa943266e9013fd6704da3d4518a27
42	ExpectedRangeHeader ParseRangeHeader(string header) {	41✔
43	RangeHeader range_header {};	41✔
44
45	std::regex content_range_regexp {R"(bytes\s+(\d+)\s?-\s?(\d+)\s?\/?\s?(\d+\|\*)?)"};	82✔
46
47	std::smatch range_matches;	82✔
48	if (!regex_match(header, range_matches, content_range_regexp)) {	41✔
49	return expected::unexpected(http::MakeError(	10✔
50	http::NoSuchHeaderError, "Invalid Content-Range returned from server: " + header));	20✔
51	}
52
53	auto exp_range_start = common::StringToLongLong(range_matches[1].str());	62✔
54	auto exp_range_end = common::StringToLongLong(range_matches[2].str());	62✔
55	if (!exp_range_start \|\| !exp_range_end) {	31✔
56	return expected::unexpected(http::MakeError(	×
57	http::NoSuchHeaderError, "Content-Range contains invalid number: " + header));	×
58	}
59	range_header.range_start = exp_range_start.value();	31✔
60	range_header.range_end = exp_range_end.value();	31✔
61
62	if (range_header.range_start > range_header.range_end) {	31✔
63	return expected::unexpected(http::MakeError(	1✔
64	http::NoSuchHeaderError, "Invalid Content-Range returned from server: " + header));	2✔
65	}
66
67	if ((range_matches[3].matched) && (range_matches[3].str() != "*")) {	30✔
68	auto exp_size = common::StringToLongLong(range_matches[3].str());	20✔
69	if (!exp_size) {	20✔
70	return expected::unexpected(http::MakeError(	×
71	http::NoSuchHeaderError, "Content-Range contains invalid number: " + header));	×
72	}
73	range_header.size = exp_size.value();	20✔
74	}
75
76	return range_header;	30✔
77	}
78
79	class HeaderHandlerFunctor {
80	public:
81	HeaderHandlerFunctor(weak_ptr<DownloadResumerClient> resumer) :	136✔
82	resumer_client_ {resumer} {};	136✔
83
84	void operator()(http::ExpectedIncomingResponsePtr exp_resp);
85
86	private:
87	void HandleFirstResponse(
88	const shared_ptr<DownloadResumerClient> &resumer_client,
89	http::ExpectedIncomingResponsePtr exp_resp);
90	void HandleNextResponse(
91	const shared_ptr<DownloadResumerClient> &resumer_client,
92	http::ExpectedIncomingResponsePtr exp_resp);
93
94	weak_ptr<DownloadResumerClient> resumer_client_;
95	};
96
97	class BodyHandlerFunctor {
98	public:
99	BodyHandlerFunctor(weak_ptr<DownloadResumerClient> resumer) :	136✔
100	resumer_client_ {resumer} {};	136✔
101
102	void operator()(http::ExpectedIncomingResponsePtr exp_resp);
103
104	private:
105	weak_ptr<DownloadResumerClient> resumer_client_;
106	};
107
108	void HeaderHandlerFunctor::operator()(http::ExpectedIncomingResponsePtr exp_resp) {	135✔
109	auto resumer_client = resumer_client_.lock();	270✔
110	if (resumer_client) {	135✔
111	if (resumer_client->resumer_state_->active_state == DownloadResumerActiveStatus::Resuming) {	135✔
112	HandleNextResponse(resumer_client, exp_resp);	53✔
113	} else {
114	HandleFirstResponse(resumer_client, exp_resp);	82✔
115	}
116	}
117	}	135✔
118
119	void HeaderHandlerFunctor::HandleFirstResponse(	82✔
120	const shared_ptr<DownloadResumerClient> &resumer_client,
121	http::ExpectedIncomingResponsePtr exp_resp) {
122	// The first response shall always call the user header callback. On resumable responses, we
123	// create a our own incoming response and call the user header handler. On errors, we log a
124	// warning and call the user handler with the original response
125
126	if (!exp_resp) {	82✔
127	resumer_client->logger_.Warning(exp_resp.error().String());	×
128	resumer_client->CallUserHandler(exp_resp);	×
129	return;	3✔
130	}
131	auto resp = exp_resp.value();	82✔
132
133	if (resp->GetStatusCode() != mender::http::StatusOK) {	82✔
134	// Non-resumable response
135	resumer_client->CallUserHandler(exp_resp);	2✔
136	return;	2✔
137	}
138
139	auto exp_header = resp->GetHeader("Content-Length");	160✔
140	if (!exp_header \|\| exp_header.value() == "0") {	80✔
141	resumer_client->logger_.Warning("Response does not contain Content-Length header");	1✔
142	resumer_client->CallUserHandler(exp_resp);	1✔
143	return;	1✔
144	}
145
146	auto exp_length = common::StringToLongLong(exp_header.value());	79✔
147	if (!exp_length \|\| exp_length.value() < 0) {	79✔
148	resumer_client->logger_.Warning(	×
149	"Content-Length contains invalid number: " + exp_header.value());	×
150	resumer_client->CallUserHandler(exp_resp);	×
151	return;	×
152	}
153
154	// Resumable response
155	resumer_client->resumer_state_->active_state = DownloadResumerActiveStatus::Resuming;	79✔
156	resumer_client->resumer_state_->offset = 0;	79✔
157	resumer_client->resumer_state_->content_length = exp_length.value();	79✔
158
159	// Prepare a modified response and call user handler
160	resumer_client->response_.reset(new http::IncomingResponse(*resumer_client, resp->cancelled_));	79✔
161	resumer_client->response_->status_code_ = resp->GetStatusCode();	79✔
162	resumer_client->response_->status_message_ = resp->GetStatusMessage();	79✔
163	resumer_client->response_->headers_ = resp->GetHeaders();	79✔
164	resumer_client->CallUserHandler(resumer_client->response_);	79✔
165	}
166
167	void HeaderHandlerFunctor::HandleNextResponse(	53✔
168	const shared_ptr<DownloadResumerClient> &resumer_client,
169	http::ExpectedIncomingResponsePtr exp_resp) {
170	// If an error occurs has already occurred, schedule the next AsyncCall directly
171	// If an error occurs during handling here, cancel the resuming and call the user handler.
172	if (!exp_resp) {	53✔
173	resumer_client->logger_.Warning(exp_resp.error().String());	11✔
174
175	auto err = resumer_client->ScheduleNextResumeRequest();	11✔
176	if (err != error::NoError) {	11✔
177	resumer_client->logger_.Error(err.String());	1✔
178	resumer_client->Cancel();	1✔
179	resumer_client->CallUserHandler(expected::unexpected(err));	1✔
180	}
181	return;	11✔
182	}
183	auto resp = exp_resp.value();	42✔
184
185	auto exp_content_range = resp->GetHeader("Content-Range").and_then(ParseRangeHeader);	84✔
186	if (!exp_content_range) {	42✔
187	resumer_client->logger_.Error(exp_content_range.error().String());	12✔
188	resumer_client->Cancel();	12✔
189	resumer_client->CallUserHandler(expected::unexpected(exp_content_range.error()));	12✔
190	return;	12✔
191	}
192
193	auto content_range = exp_content_range.value();	30✔
194	if (content_range.size != 0	60✔
195	&& content_range.size != resumer_client->resumer_state_->content_length) {	30✔
196	auto size_changed_err = http::MakeError(
197	http::DownloadResumerError,
198	"Size of artifact changed after download was resumed (expected "
199	+ to_string(resumer_client->resumer_state_->content_length) + ", got "	4✔
200	+ to_string(content_range.size) + ")");	6✔
201	resumer_client->logger_.Error(size_changed_err.String());	2✔
202	resumer_client->Cancel();	2✔
203	resumer_client->CallUserHandler(expected::unexpected(size_changed_err));	2✔
204	return;	2✔
205	}
206
207	if ((content_range.range_end != resumer_client->resumer_state_->content_length - 1)	28✔
208	\|\| (content_range.range_start != resumer_client->resumer_state_->offset)) {	28✔
209	auto bad_range_err = http::MakeError(
210	http::DownloadResumerError,
211	"HTTP server returned an different range than requested. Requested "
212	+ to_string(resumer_client->resumer_state_->offset) + "-"	4✔
213	+ to_string(resumer_client->resumer_state_->content_length - 1) + ", got "	8✔
214	+ to_string(content_range.range_start) + "-" + to_string(content_range.range_end));	8✔
215	resumer_client->logger_.Error(bad_range_err.String());	2✔
216	resumer_client->Cancel();	2✔
217	resumer_client->CallUserHandler(expected::unexpected(bad_range_err));	2✔
218	return;	2✔
219	}
220
221	// Get the reader for the new response
222	auto exp_reader = resumer_client->client_.MakeBodyAsyncReader(resp);	26✔
223	if (!exp_reader) {	26✔
224	auto bad_range_err = exp_reader.error().WithContext("cannot get the reader after resume");	×
225	resumer_client->logger_.Error(bad_range_err.String());	×
226	resumer_client->Cancel();	×
227	resumer_client->CallUserHandler(expected::unexpected(bad_range_err));	×
228	return;	×
229	}
230	// Update the inner reader of the user reader
231	resumer_client->resumer_reader_->inner_reader_ = exp_reader.value();	26✔
232
233	// Resume reading reusing last user data (start, end, handler)
234	auto err = resumer_client->resumer_reader_->AsyncReadResume();	26✔
235	if (err != error::NoError) {	26✔
236	auto bad_read_err = err.WithContext("error reading after resume");	×
237	resumer_client->logger_.Error(bad_read_err.String());	×
238	resumer_client->Cancel();	×
239	resumer_client->CallUserHandler(expected::unexpected(bad_read_err));	×
240	return;	×
241	}
242	}
243
244	void BodyHandlerFunctor::operator()(http::ExpectedIncomingResponsePtr exp_resp) {	124✔
245	auto resumer_client = resumer_client_.lock();	124✔
246	if (!resumer_client) {	124✔
247	return;	51✔
248	}
249
250	if (*resumer_client->cancelled_) {	73✔
251	resumer_client->CallUserHandler(exp_resp);	19✔
252	return;	19✔
253	}
254
255	if (resumer_client->resumer_state_->active_state == DownloadResumerActiveStatus::Inactive) {	54✔
256	resumer_client->CallUserHandler(exp_resp);	2✔
257	return;	2✔
258	}
259
260	// We resume the download if either:
261	// * there is any error or
262	// * successful read with status code Partial Content and there is still data missing
263	const bool is_range_response =
264	exp_resp && exp_resp.value()->GetStatusCode() == mender::http::StatusPartialContent;	52✔
265	const bool is_data_missing =
266	resumer_client->resumer_state_->offset < resumer_client->resumer_state_->content_length;	52✔
267	if (!exp_resp \|\| (is_range_response && is_data_missing)) {	52✔
268	if (!exp_resp) {	43✔
269	resumer_client->logger_.Info(	86✔
270	"Will try to resume after error " + exp_resp.error().String());	86✔
271	}
272
273	auto err = resumer_client->ScheduleNextResumeRequest();	43✔
274	if (err != error::NoError) {	43✔
275	resumer_client->logger_.Error(err.String());	×
276	resumer_client->Cancel();	×
277	resumer_client->CallUserHandler(expected::unexpected(err));	×
278	return;	×
279	}
280	} else {
281	// Update headers with the last received server response. When resuming has taken place,
282	// the user will get different headers on header and body handlers, representing (somehow)
283	// what the resumer has been doing in its behalf.
284	auto resp = exp_resp.value();	9✔
285	resumer_client->response_->status_code_ = resp->GetStatusCode();	9✔
286	resumer_client->response_->status_message_ = resp->GetStatusMessage();	9✔
287	resumer_client->response_->headers_ = resp->GetHeaders();	9✔
288
289	// Finished, call the user handler \o/
290	resumer_client->logger_.Debug("Download resumed and completed successfully");	9✔
291	resumer_client->DoCancel();	9✔
292	resumer_client->CallUserHandler(resumer_client->response_);	9✔
293	}
294	}
295
296	void DownloadResumerAsyncReader::Cancel() {	×
297	if (!*cancelled_) {	×
298	inner_reader_->Cancel();	×
299	}
300	}	×
301
302	error::Error DownloadResumerAsyncReader::AsyncRead(	2,032✔
303	vector<uint8_t>::iterator start, vector<uint8_t>::iterator end, io::AsyncIoHandler handler) {
304	auto resumer_client = resumer_client_.lock();	4,064✔
305	if (!resumer_client \|\| *cancelled_) {	2,032✔
306	return error::MakeError(
307	error::ProgrammingError,
308	"DownloadResumerAsyncReader::AsyncRead called after stream is destroyed");	×
309	}
310	// Save user parameters for further resumes of the body read
311	resumer_client->last_read_ = {.start = start, .end = end, .handler = handler};	2,032✔
312	return AsyncReadResume();	2,032✔
313	}
314
315	error::Error DownloadResumerAsyncReader::AsyncReadResume() {	2,058✔
316	auto resumer_client = resumer_client_.lock();	4,116✔
317	if (!resumer_client) {	2,058✔
318	return error::MakeError(
319	error::ProgrammingError,
320	"DownloadResumerAsyncReader::AsyncReadResume called after client is destroyed");	×
321	}
322	return inner_reader_->AsyncRead(	2,058✔
323	resumer_client->last_read_.start,	2,058✔
324	resumer_client->last_read_.end,	2,058✔
325	[this](io::ExpectedSize result) {	8,185✔
326	if (!result) {	2,057✔
327	inner_reader_.reset();	43✔
328
329	logger_.Warning(	43✔
330	"Reading error, a new request will be re-scheduled. "
331	+ result.error().String());	86✔
332	} else {
333	resumer_state_->offset += result.value();	2,014✔
334	logger_.Debug("read " + to_string(result.value()) + " bytes");	2,014✔
335	auto resumer_client = resumer_client_.lock();	4,028✔
336	if (resumer_client) {	2,014✔
337	resumer_client->last_read_.handler(result);	2,014✔
338	} else {
339	logger_.Error(	×
340	"AsyncRead finish handler called after resumer client has been destroyed.");	×
341	}
342	}
343	});	6,173✔
344	}
345
346	DownloadResumerClient::DownloadResumerClient(	×
347	const http::ClientConfig &config, events::EventLoop &event_loop) :	119✔
348	resumer_state_ {make_shared<DownloadResumerClientState>()},
349	client_(config, event_loop, "http_resumer:client"),
350	logger_ {"http_resumer:client"},
351	cancelled_ {make_shared<bool>(true)},	×
352	retry_ {
353	.backoff = http::ExponentialBackoff(chrono::minutes(1), 10),	×
354	.wait_timer = events::Timer(event_loop)} {	×
355	}	×
356
357	DownloadResumerClient::~DownloadResumerClient() {	×
358	if (!*cancelled_) {	×
359	logger_.Warning("DownloadResumerClient destroyed while request is still active!");	×
360	}
361	client_.Cancel();	×
362	}	×
363
364	error::Error DownloadResumerClient::AsyncCall(	83✔
365	http::OutgoingRequestPtr req,
366	http::ResponseHandler user_header_handler,
367	http::ResponseHandler user_body_handler) {
368	HeaderHandlerFunctor resumer_header_handler {shared_from_this()};	249✔
369	BodyHandlerFunctor resumer_body_handler {shared_from_this()};	249✔
370
371	user_request_ = req;	83✔
372	user_header_handler_ = user_header_handler;	83✔
373	user_body_handler_ = user_body_handler;	83✔
374
375	if (!*cancelled_) {	83✔
376	return error::Error(
377	make_error_condition(errc::operation_in_progress), "HTTP call already ongoing");	2✔
378	}
379
380	*cancelled_ = false;	82✔
381	retry_.backoff.Reset();	82✔
382	resumer_state_->active_state = DownloadResumerActiveStatus::Inactive;	82✔
383	resumer_state_->user_handlers_state = DownloadResumerUserHandlersStatus::None;	82✔
384	return client_.AsyncCall(req, resumer_header_handler, resumer_body_handler);	82✔
385	}
386
387	io::ExpectedAsyncReaderPtr DownloadResumerClient::MakeBodyAsyncReader(	79✔
388	http::IncomingResponsePtr resp) {
389	auto exp_reader = client_.MakeBodyAsyncReader(resp);	158✔
390	if (!exp_reader) {	79✔
391	return exp_reader;	1✔
392	}
393	resumer_reader_ = make_shared<DownloadResumerAsyncReader>(	78✔
394	exp_reader.value(), resumer_state_, cancelled_, shared_from_this());	156✔
395	return resumer_reader_;	78✔
396	}
397
398	http::OutgoingRequestPtr DownloadResumerClient::RemainingRangeRequest() const {	53✔
399	auto range_req = make_shared<http::OutgoingRequest>(*user_request_);	53✔
400	range_req->SetHeader(	106✔
401	"Range",
402	"bytes=" + to_string(resumer_state_->offset) + "-"	106✔
403	+ to_string(resumer_state_->content_length - 1));	212✔
404	return range_req;	53✔
405	};
406
407	error::Error DownloadResumerClient::ScheduleNextResumeRequest() {	54✔
408	auto exp_interval = retry_.backoff.NextInterval();	108✔
409	if (!exp_interval) {	54✔
410	return http::MakeError(
411	http::DownloadResumerError,
412	"Giving up on resuming the download: " + exp_interval.error().String());	2✔
413	}
414
415	auto interval = exp_interval.value();	53✔
416	logger_.Info(	53✔
417	"Resuming download after " + to_string(chrono::milliseconds(interval).count() / 1000)	106✔
418	+ " seconds");	106✔
419
420	HeaderHandlerFunctor resumer_next_header_handler {shared_from_this()};	159✔
421	BodyHandlerFunctor resumer_next_body_handler {shared_from_this()};	159✔
422
423	retry_.wait_timer.AsyncWait(	53✔
424	interval, [this, resumer_next_header_handler, resumer_next_body_handler](error::Error err) {	159✔
425	if (err != error::NoError) {	53✔
426	auto err_user = http::MakeError(
427	http::DownloadResumerError, "Unexpected error in wait timer: " + err.String());	×
428	logger_.Error(err_user.String());	×
429	Cancel();	×
430	CallUserHandler(expected::unexpected(err_user));	×
431	return;	×
432	}
433
434	auto next_call_err = client_.AsyncCall(
435	RemainingRangeRequest(), resumer_next_header_handler, resumer_next_body_handler);	159✔
436	if (next_call_err != error::NoError) {	53✔
437	// Schedule once more
438	auto err = ScheduleNextResumeRequest();	×
439	if (err != error::NoError) {	×
440	logger_.Error(err.String());	×
441	Cancel();	×
442	CallUserHandler(expected::unexpected(err));	×
443	}
444	}
445	});	106✔
446
447	return error::NoError;	53✔
448	}
449
450	void DownloadResumerClient::CallUserHandler(http::ExpectedIncomingResponsePtr exp_resp) {	129✔
451	if (resumer_state_->user_handlers_state == DownloadResumerUserHandlersStatus::None) {	129✔
452	resumer_state_->user_handlers_state =	82✔
453	DownloadResumerUserHandlersStatus::HeaderHandlerCalled;
454	user_header_handler_(exp_resp);	82✔
455	} else if (	47✔
456	resumer_state_->user_handlers_state	47✔
457	== DownloadResumerUserHandlersStatus::HeaderHandlerCalled) {	47✔
458	resumer_state_->user_handlers_state = DownloadResumerUserHandlersStatus::BodyHandlerCalled;	31✔
459	user_body_handler_(exp_resp);	31✔
460	} else {
461	string msg;	16✔
462	if (!exp_resp) {	16✔
463	msg = "error: " + exp_resp.error().String();	16✔
464	} else {
465	auto &resp = exp_resp.value();	×
466	msg = "response: " + to_string(resp->GetStatusCode()) + " " + resp->GetStatusMessage();	×
467	}
468	logger_.Warning("Cannot call any user handler with " + msg);	16✔
469	}
470	}	129✔
471
472	void DownloadResumerClient::Cancel() {	20✔
473	DoCancel();	20✔
474	client_.Cancel();	20✔
475	};	20✔
476
477	void DownloadResumerClient::DoCancel() {	29✔
478	// Set cancel state and then make a new one. Those who are interested should have their own
479	// pointer to the old one.
480	*cancelled_ = true;	29✔
481	cancelled_ = make_shared<bool>(true);	29✔
482	};	29✔
483
484	} // namespace http_resumer
485	} // namespace update
486	} // namespace mender

mendersoftware / mender / 1019656555

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