downloadCached: Return ETag

(cherry picked from commit 529add316c5356a8060c35f987643b7bf5c796dc)
This commit is contained in:
Eelco Dolstra 2019-02-25 23:20:50 +08:00
parent 94f11d0a61
commit dc29e9fb47
No known key found for this signature in database
GPG key ID: 8170B4726D7198DE
6 changed files with 29 additions and 12 deletions

View file

@ -46,7 +46,7 @@ Bindings * MixEvalArgs::getAutoArgs(EvalState & state)
Path lookupFileArg(EvalState & state, string s)
{
if (isUri(s))
return getDownloader()->downloadCached(state.store, s, true);
return getDownloader()->downloadCached(state.store, s, true).path;
else if (s.size() > 2 && s.at(0) == '<' && s.at(s.size() - 1) == '>') {
Path p = s.substr(1, s.size() - 2);
return state.findFile(p);

View file

@ -677,7 +677,7 @@ std::pair<bool, std::string> EvalState::resolveSearchPathElem(const SearchPathEl
if (isUri(elem.second)) {
try {
res = { true, getDownloader()->downloadCached(store, elem.second, true) };
res = { true, getDownloader()->downloadCached(store, elem.second, true).path };
} catch (DownloadError & e) {
printError(format("warning: Nix search path entry '%1%' cannot be downloaded, ignoring") % elem.second);
res = { false, "" };

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@ -2083,7 +2083,7 @@ void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
if (evalSettings.pureEval && !expectedHash)
throw Error("in pure evaluation mode, '%s' requires a 'sha256' argument", who);
Path res = getDownloader()->downloadCached(state.store, url, unpack, name, expectedHash);
Path res = getDownloader()->downloadCached(state.store, url, unpack, name, expectedHash).path;
if (state.allowedPaths)
state.allowedPaths->insert(res);

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@ -790,7 +790,7 @@ void Downloader::download(DownloadRequest && request, Sink & sink)
}
}
Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpack, string name, const Hash & expectedHash, string * effectiveUrl, int ttl)
CachedDownloadResult Downloader::downloadCached(ref<Store> store, const string & url_, bool unpack, string name, const Hash & expectedHash, string * effectiveUrl, int ttl)
{
auto url = resolveUri(url_);
@ -802,8 +802,11 @@ Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpa
Path expectedStorePath;
if (expectedHash) {
expectedStorePath = store->makeFixedOutputPath(unpack, expectedHash, name);
if (store->isValidPath(expectedStorePath))
return store->toRealPath(expectedStorePath);
if (store->isValidPath(expectedStorePath)) {
CachedDownloadResult result;
result.path = store->toRealPath(expectedStorePath);
return result;
}
}
Path cacheDir = getCacheDir() + "/nix/tarballs";
@ -822,6 +825,8 @@ Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpa
bool skip = false;
CachedDownloadResult result;
if (pathExists(fileLink) && pathExists(dataFile)) {
storePath = readLink(fileLink);
store->addTempRoot(storePath);
@ -833,6 +838,7 @@ Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpa
skip = true;
if (effectiveUrl)
*effectiveUrl = url_;
result.etag = ss[1];
} else if (!ss[1].empty()) {
debug(format("verifying previous ETag '%1%'") % ss[1]);
expectedETag = ss[1];
@ -850,6 +856,7 @@ Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpa
auto res = download(request);
if (effectiveUrl)
*effectiveUrl = res.effectiveUrl;
result.etag = res.etag;
if (!res.cached) {
ValidPathInfo info;
@ -871,6 +878,7 @@ Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpa
} catch (DownloadError & e) {
if (storePath.empty()) throw;
printError(format("warning: %1%; using cached result") % e.msg());
result.etag = expectedETag;
}
}
@ -904,7 +912,8 @@ Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpa
url, expectedHash.to_string(), gotHash.to_string());
}
return store->toRealPath(storePath);
result.path = store->toRealPath(storePath);
return result;
}

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@ -41,6 +41,12 @@ struct DownloadResult
uint64_t bodySize = 0;
};
struct CachedDownloadResult
{
Path path;
std::optional<std::string> etag;
};
class Store;
struct Downloader
@ -64,8 +70,10 @@ struct Downloader
and is more recent than tarball-ttl seconds. Otherwise,
use the recorded ETag to verify if the server has a more
recent version, and if so, download it to the Nix store. */
Path downloadCached(ref<Store> store, const string & uri, bool unpack, string name = "",
const Hash & expectedHash = Hash(), string * effectiveUri = nullptr, int ttl = settings.tarballTtl);
CachedDownloadResult downloadCached(
ref<Store> store, const string & uri, bool unpack, string name = "",
const Hash & expectedHash = Hash(), string * effectiveUri = nullptr,
int ttl = settings.tarballTtl);
enum Error { NotFound, Forbidden, Misc, Transient, Interrupted };
};

View file

@ -88,7 +88,7 @@ static void update(const StringSet & channelNames)
// definition from a consistent location if the redirect changes mid-download.
std::string effectiveUrl;
auto dl = getDownloader();
auto filename = dl->downloadCached(store, url, false, "", Hash(), &effectiveUrl, 0);
auto filename = dl->downloadCached(store, url, false, "", Hash(), &effectiveUrl, 0).path;
url = chomp(std::move(effectiveUrl));
// If the URL contains a version number, append it to the name
@ -123,10 +123,10 @@ static void update(const StringSet & channelNames)
// Download the channel tarball.
auto fullURL = url + "/nixexprs.tar.xz";
try {
filename = dl->downloadCached(store, fullURL, false);
filename = dl->downloadCached(store, fullURL, false).path;
} catch (DownloadError & e) {
fullURL = url + "/nixexprs.tar.bz2";
filename = dl->downloadCached(store, fullURL, false);
filename = dl->downloadCached(store, fullURL, false).path;
}
chomp(filename);
}