forked from lix-project/lix
78fa47a7f0
Once we've started writing data to a Sink, we can't restart a download
request, because then we end up writing duplicate data to the
Sink. Therefore we shouldn't handle retries in Downloader but at a
higher level (in particular, in copyStorePath()).
Fixes #2952.
(cherry picked from commit a67cf5a358)
110 lines
2.9 KiB
C++
110 lines
2.9 KiB
C++
#pragma once
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#include "types.hh"
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#include "hash.hh"
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#include "globals.hh"
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#include <string>
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#include <future>
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namespace nix {
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struct DownloadRequest
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{
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std::string uri;
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std::string expectedETag;
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bool verifyTLS = true;
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bool head = false;
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size_t tries = 5;
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unsigned int baseRetryTimeMs = 250;
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ActivityId parentAct;
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bool decompress = true;
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std::shared_ptr<std::string> data;
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std::string mimeType;
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std::function<void(char *, size_t)> dataCallback;
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DownloadRequest(const std::string & uri)
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: uri(uri), parentAct(getCurActivity()) { }
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std::string verb()
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{
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return data ? "upload" : "download";
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}
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};
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struct DownloadResult
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{
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bool cached = false;
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std::string etag;
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std::string effectiveUrl;
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std::shared_ptr<std::string> data;
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uint64_t bodySize = 0;
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};
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struct CachedDownloadResult
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{
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// Note: 'storePath' may be different from 'path' when using a
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// chroot store.
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Path storePath;
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Path path;
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std::optional<std::string> etag;
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};
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class Store;
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struct Downloader
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{
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/* Enqueue a download request, returning a future to the result of
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the download. The future may throw a DownloadError
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exception. */
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virtual void enqueueDownload(const DownloadRequest & request,
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Callback<DownloadResult> callback) = 0;
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std::future<DownloadResult> enqueueDownload(const DownloadRequest & request);
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/* Synchronously download a file. The request will be retried in
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case of transient failures. */
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DownloadResult download(const DownloadRequest & request);
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/* Download a file, writing its data to a sink. The sink will be
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invoked on the thread of the caller. The request will not be
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retried in case of transient failures. */
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void download(DownloadRequest && request, Sink & sink);
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/* Check if the specified file is already in ~/.cache/nix/tarballs
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and is more recent than ‘tarball-ttl’ seconds. Otherwise,
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use the recorded ETag to verify if the server has a more
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recent version, and if so, download it to the Nix store. */
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CachedDownloadResult downloadCached(
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ref<Store> store, const string & uri, bool unpack, string name = "",
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const Hash & expectedHash = Hash(), string * effectiveUri = nullptr,
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int ttl = settings.tarballTtl);
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enum Error { NotFound, Forbidden, Misc, Transient, Interrupted };
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};
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/* Return a shared Downloader object. Using this object is preferred
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because it enables connection reuse and HTTP/2 multiplexing. */
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ref<Downloader> getDownloader();
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/* Return a new Downloader object. */
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ref<Downloader> makeDownloader();
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class DownloadError : public Error
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{
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public:
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Downloader::Error error;
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DownloadError(Downloader::Error error, const FormatOrString & fs)
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: Error(fs), error(error)
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{ }
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bool isTransient() override
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{
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return error == Downloader::Error::Transient;
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}
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};
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bool isUri(const string & s);
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}
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