lix/src/libstore/http-binary-cache-store.cc
Eelco Dolstra 7348653ff4
Ensure that Callback is called only once
Also, make Callback movable but uncopyable.
2019-09-03 13:45:35 +02:00

174 lines
5 KiB
C++

#include "binary-cache-store.hh"
#include "download.hh"
#include "globals.hh"
#include "nar-info-disk-cache.hh"
namespace nix {
MakeError(UploadToHTTP, Error);
class HttpBinaryCacheStore : public BinaryCacheStore
{
private:
Path cacheUri;
struct State
{
bool enabled = true;
std::chrono::steady_clock::time_point disabledUntil;
};
Sync<State> _state;
public:
HttpBinaryCacheStore(
const Params & params, const Path & _cacheUri)
: BinaryCacheStore(params)
, cacheUri(_cacheUri)
{
if (cacheUri.back() == '/')
cacheUri.pop_back();
diskCache = getNarInfoDiskCache();
}
std::string getUri() override
{
return cacheUri;
}
void init() override
{
// FIXME: do this lazily?
if (!diskCache->cacheExists(cacheUri, wantMassQuery_, priority)) {
try {
BinaryCacheStore::init();
} catch (UploadToHTTP &) {
throw Error("'%s' does not appear to be a binary cache", cacheUri);
}
diskCache->createCache(cacheUri, storeDir, wantMassQuery_, priority);
}
}
protected:
void maybeDisable()
{
auto state(_state.lock());
if (state->enabled && settings.tryFallback) {
int t = 60;
printError("disabling binary cache '%s' for %s seconds", getUri(), t);
state->enabled = false;
state->disabledUntil = std::chrono::steady_clock::now() + std::chrono::seconds(t);
}
}
void checkEnabled()
{
auto state(_state.lock());
if (state->enabled) return;
if (std::chrono::steady_clock::now() > state->disabledUntil) {
state->enabled = true;
debug("re-enabling binary cache '%s'", getUri());
return;
}
throw SubstituterDisabled("substituter '%s' is disabled", getUri());
}
bool fileExists(const std::string & path) override
{
checkEnabled();
try {
DownloadRequest request(cacheUri + "/" + path);
request.head = true;
getDownloader()->download(request);
return true;
} catch (DownloadError & e) {
/* S3 buckets return 403 if a file doesn't exist and the
bucket is unlistable, so treat 403 as 404. */
if (e.error == Downloader::NotFound || e.error == Downloader::Forbidden)
return false;
maybeDisable();
throw;
}
}
void upsertFile(const std::string & path,
const std::string & data,
const std::string & mimeType) override
{
auto req = DownloadRequest(cacheUri + "/" + path);
req.data = std::make_shared<string>(data); // FIXME: inefficient
req.mimeType = mimeType;
try {
getDownloader()->download(req);
} catch (DownloadError & e) {
throw UploadToHTTP("while uploading to HTTP binary cache at '%s': %s", cacheUri, e.msg());
}
}
DownloadRequest makeRequest(const std::string & path)
{
DownloadRequest request(cacheUri + "/" + path);
return request;
}
void getFile(const std::string & path, Sink & sink) override
{
checkEnabled();
auto request(makeRequest(path));
try {
getDownloader()->download(std::move(request), sink);
} catch (DownloadError & e) {
if (e.error == Downloader::NotFound || e.error == Downloader::Forbidden)
throw NoSuchBinaryCacheFile("file '%s' does not exist in binary cache '%s'", path, getUri());
maybeDisable();
throw;
}
}
void getFile(const std::string & path,
Callback<std::shared_ptr<std::string>> callback) override
{
checkEnabled();
auto request(makeRequest(path));
auto callbackPtr = std::make_shared<decltype(callback)>(std::move(callback));
getDownloader()->enqueueDownload(request,
{[callbackPtr, this](std::future<DownloadResult> result) {
try {
(*callbackPtr)(result.get().data);
} catch (DownloadError & e) {
if (e.error == Downloader::NotFound || e.error == Downloader::Forbidden)
return (*callbackPtr)(std::shared_ptr<std::string>());
maybeDisable();
callbackPtr->rethrow();
} catch (...) {
callbackPtr->rethrow();
}
}});
}
};
static RegisterStoreImplementation regStore([](
const std::string & uri, const Store::Params & params)
-> std::shared_ptr<Store>
{
if (std::string(uri, 0, 7) != "http://" &&
std::string(uri, 0, 8) != "https://" &&
(getEnv("_NIX_FORCE_HTTP_BINARY_CACHE_STORE") != "1" || std::string(uri, 0, 7) != "file://")
) return 0;
auto store = std::make_shared<HttpBinaryCacheStore>(params, uri);
store->init();
return store;
});
}