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Refactor downloadCached() interface 

(cherry picked from commit df3f5a78d5)
This commit is contained in:
Eelco Dolstra 2019-05-22 23:36:29 +02:00
parent 7b9c68766d
commit f8b30338ac
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GPG Key ID: 8170B4726D7198DE
6 changed files with 63 additions and 49 deletions
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8
src/libexpr/common-eval-args.cc
View File

@ -45,9 +45,11 @@ Bindings * MixEvalArgs::getAutoArgs(EvalState & state)
Path lookupFileArg(EvalState & state, string s)
{
if (isUri(s))
return getDownloader()->downloadCached(state.store, s, true).path;
else if (s.size() > 2 && s.at(0) == '<' && s.at(s.size() - 1) == '>') {
if (isUri(s)) {
CachedDownloadRequest request(s);
request.unpack = true;
return getDownloader()->downloadCached(state.store, request).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);
} else

4
src/libexpr/parser.y
View File

@ -677,7 +677,9 @@ std::pair<bool, std::string> EvalState::resolveSearchPathElem(const SearchPathEl
if (isUri(elem.second)) {
try {
res = { true, getDownloader()->downloadCached(store, elem.second, true).path };
CachedDownloadRequest request(elem.second);
request.unpack = true;
res = { true, getDownloader()->downloadCached(store, request).path };
} catch (DownloadError & e) {
printError(format("warning: Nix search path entry '%1%' cannot be downloaded, ignoring") % elem.second);
res = { false, "" };

22
src/libexpr/primops.cc
View File

@ -2050,9 +2050,9 @@ static void prim_splitVersion(EvalState & state, const Pos & pos, Value * * args
void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
const string & who, bool unpack, const std::string & defaultName)
{
string url;
Hash expectedHash;
string name = defaultName;
CachedDownloadRequest request("");
request.unpack = unpack;
request.name = defaultName;
state.forceValue(*args[0]);
@ -2063,27 +2063,27 @@ void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
for (auto & attr : *args[0]->attrs) {
string n(attr.name);
if (n == "url")
url = state.forceStringNoCtx(*attr.value, *attr.pos);
request.uri = state.forceStringNoCtx(*attr.value, *attr.pos);
else if (n == "sha256")
expectedHash = Hash(state.forceStringNoCtx(*attr.value, *attr.pos), htSHA256);
request.expectedHash = Hash(state.forceStringNoCtx(*attr.value, *attr.pos), htSHA256);
else if (n == "name")
name = state.forceStringNoCtx(*attr.value, *attr.pos);
request.name = state.forceStringNoCtx(*attr.value, *attr.pos);
else
throw EvalError(format("unsupported argument '%1%' to '%2%', at %3%") % attr.name % who % attr.pos);
}
if (url.empty())
if (request.uri.empty())
throw EvalError(format("'url' argument required, at %1%") % pos);
} else
url = state.forceStringNoCtx(*args[0], pos);
request.uri = state.forceStringNoCtx(*args[0], pos);
state.checkURI(url);
state.checkURI(request.uri);
if (evalSettings.pureEval && !expectedHash)
if (evalSettings.pureEval && !request.expectedHash)
throw Error("in pure evaluation mode, '%s' requires a 'sha256' argument", who);
Path res = getDownloader()->downloadCached(state.store, url, unpack, name, expectedHash).path;
Path res = getDownloader()->downloadCached(state.store, request).path;
if (state.allowedPaths)
state.allowedPaths->insert(res);

44
src/libstore/download.cc
View File

@ -293,10 +293,10 @@ struct CurlDownloader : public Downloader
long httpStatus = 0;
curl_easy_getinfo(req, CURLINFO_RESPONSE_CODE, &httpStatus);
char * effectiveUrlCStr;
curl_easy_getinfo(req, CURLINFO_EFFECTIVE_URL, &effectiveUrlCStr);
if (effectiveUrlCStr)
result.effectiveUrl = effectiveUrlCStr;
char * effectiveUriCStr;
curl_easy_getinfo(req, CURLINFO_EFFECTIVE_URL, &effectiveUriCStr);
if (effectiveUriCStr)
result.effectiveUri = effectiveUriCStr;
debug("finished %s of '%s'; curl status = %d, HTTP status = %d, body = %d bytes",
request.verb(), request.uri, code, httpStatus, result.bodySize);
@ -737,18 +737,20 @@ void Downloader::download(DownloadRequest && request, Sink & sink)
}
}
CachedDownloadResult 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 CachedDownloadRequest & request)
{
auto url = resolveUri(url_);
auto url = resolveUri(request.uri);
auto name = request.name;
if (name == "") {
auto p = url.rfind('/');
if (p != string::npos) name = string(url, p + 1);
}
Path expectedStorePath;
if (expectedHash) {
expectedStorePath = store->makeFixedOutputPath(unpack, expectedHash, name);
if (request.expectedHash) {
expectedStorePath = store->makeFixedOutputPath(request.unpack, request.expectedHash, name);
if (store->isValidPath(expectedStorePath)) {
CachedDownloadResult result;
result.storePath = expectedStorePath;
@ -782,10 +784,9 @@ CachedDownloadResult Downloader::downloadCached(ref<Store> store, const string &
auto ss = tokenizeString<vector<string>>(readFile(dataFile), "\n");
if (ss.size() >= 3 && ss[0] == url) {
time_t lastChecked;
if (string2Int(ss[2], lastChecked) && lastChecked + ttl >= time(0)) {
if (string2Int(ss[2], lastChecked) && lastChecked + request.ttl >= time(0)) {
skip = true;
if (effectiveUrl)
*effectiveUrl = url_;
result.effectiveUri = request.uri;
result.etag = ss[1];
} else if (!ss[1].empty()) {
debug(format("verifying previous ETag '%1%'") % ss[1]);
@ -799,18 +800,17 @@ CachedDownloadResult Downloader::downloadCached(ref<Store> store, const string &
if (!skip) {
try {
DownloadRequest request(url);
request.expectedETag = expectedETag;
auto res = download(request);
if (effectiveUrl)
*effectiveUrl = res.effectiveUrl;
DownloadRequest request2(url);
request2.expectedETag = expectedETag;
auto res = download(request2);
result.effectiveUri = res.effectiveUri;
result.etag = res.etag;
if (!res.cached) {
ValidPathInfo info;
StringSink sink;
dumpString(*res.data, sink);
Hash hash = hashString(expectedHash ? expectedHash.type : htSHA256, *res.data);
Hash hash = hashString(request.expectedHash ? request.expectedHash.type : htSHA256, *res.data);
info.path = store->makeFixedOutputPath(false, hash, name);
info.narHash = hashString(htSHA256, *sink.s);
info.narSize = sink.s->size();
@ -830,7 +830,7 @@ CachedDownloadResult Downloader::downloadCached(ref<Store> store, const string &
}
}
if (unpack) {
if (request.unpack) {
Path unpackedLink = cacheDir + "/" + baseNameOf(storePath) + "-unpacked";
PathLocks lock2({unpackedLink}, fmt("waiting for lock on '%1%'...", unpackedLink));
Path unpackedStorePath;
@ -853,11 +853,11 @@ CachedDownloadResult Downloader::downloadCached(ref<Store> store, const string &
}
if (expectedStorePath != "" && storePath != expectedStorePath) {
Hash gotHash = unpack
? hashPath(expectedHash.type, store->toRealPath(storePath)).first
: hashFile(expectedHash.type, store->toRealPath(storePath));
Hash gotHash = request.unpack
? hashPath(request.expectedHash.type, store->toRealPath(storePath)).first
: hashFile(request.expectedHash.type, store->toRealPath(storePath));
throw nix::Error("hash mismatch in file downloaded from '%s':\n wanted: %s\n got: %s",
url, expectedHash.to_string(), gotHash.to_string());
url, request.expectedHash.to_string(), gotHash.to_string());
}
result.storePath = storePath;

20
src/libstore/download.hh
View File

@ -57,11 +57,23 @@ struct DownloadResult
{
bool cached = false;
std::string etag;
std::string effectiveUrl;
std::string effectiveUri;
std::shared_ptr<std::string> data;
uint64_t bodySize = 0;
};
struct CachedDownloadRequest
{
std::string uri;
bool unpack = false;
std::string name;
Hash expectedHash;
unsigned int ttl = settings.tarballTtl;
CachedDownloadRequest(const std::string & uri)
: uri(uri) { }
};
struct CachedDownloadResult
{
// Note: 'storePath' may be different from 'path' when using a
@ -69,6 +81,7 @@ struct CachedDownloadResult
Path storePath;
Path path;
std::optional<std::string> etag;
std::string effectiveUri;
};
class Store;
@ -96,10 +109,7 @@ 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. */
CachedDownloadResult 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 CachedDownloadRequest & request);
enum Error { NotFound, Forbidden, Misc, Transient, Interrupted };
};

14
src/nix-channel/nix-channel.cc
View File

@ -86,10 +86,12 @@ static void update(const StringSet & channelNames)
// We want to download the url to a file to see if it's a tarball while also checking if we
// got redirected in the process, so that we can grab the various parts of a nix channel
// definition from a consistent location if the redirect changes mid-download.
std::string effectiveUrl;
CachedDownloadRequest request(url);
request.ttl = 0;
auto dl = getDownloader();
auto filename = dl->downloadCached(store, url, false, "", Hash(), &effectiveUrl, 0).path;
url = chomp(std::move(effectiveUrl));
auto result = dl->downloadCached(store, request);
auto filename = result.path;
url = chomp(result.effectiveUri);
// If the URL contains a version number, append it to the name
// attribute (so that "nix-env -q" on the channels profile
@ -121,12 +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).path;
filename = dl->downloadCached(store, CachedDownloadRequest(url + "/nixexprs.tar.xz")).path;
} catch (DownloadError & e) {
fullURL = url + "/nixexprs.tar.bz2";
filename = dl->downloadCached(store, fullURL, false).path;
filename = dl->downloadCached(store, CachedDownloadRequest(url + "/nixexprs.tar.bz2")).path;
}
chomp(filename);
}