lix/src/libstore/s3-binary-cache-store.cc

#include "s3-binary-cache-store.hh"
#include "nar-info.hh"
#include "nar-info-disk-cache.hh"
#include "globals.hh"

#include <aws/core/client/ClientConfiguration.h>
#include <aws/s3/S3Client.h>
#include <aws/s3/model/CreateBucketRequest.h>
#include <aws/s3/model/GetBucketLocationRequest.h>
#include <aws/s3/model/GetObjectRequest.h>
#include <aws/s3/model/HeadObjectRequest.h>
#include <aws/s3/model/PutObjectRequest.h>

namespace nix {

struct S3Error : public Error
{
    Aws::S3::S3Errors err;
    S3Error(Aws::S3::S3Errors err, const FormatOrString & fs)
        : Error(fs), err(err) { };
};

/* Helper: given an Outcome<R, E>, return R in case of success, or
   throw an exception in case of an error. */
template<typename R, typename E>
R && checkAws(const FormatOrString & fs, Aws::Utils::Outcome<R, E> && outcome)
{
    if (!outcome.IsSuccess())
        throw S3Error(
            outcome.GetError().GetErrorType(),
            fs.s + ": " + outcome.GetError().GetMessage());
    return outcome.GetResultWithOwnership();
}

struct S3BinaryCacheStoreImpl : public S3BinaryCacheStore
{
    std::string bucketName;

    ref<Aws::Client::ClientConfiguration> config;
    ref<Aws::S3::S3Client> client;

    Stats stats;

    S3BinaryCacheStoreImpl(std::shared_ptr<Store> localStore,
        const Path & secretKeyFile, const std::string & bucketName)
        : S3BinaryCacheStore(localStore, secretKeyFile)
        , bucketName(bucketName)
        , config(makeConfig())
        , client(make_ref<Aws::S3::S3Client>(*config))
    {
        diskCache = getNarInfoDiskCache();
    }

    std::string getUri()
    {
        return "s3://" + bucketName;
    }

    ref<Aws::Client::ClientConfiguration> makeConfig()
    {
        auto res = make_ref<Aws::Client::ClientConfiguration>();
        res->region = Aws::Region::US_EAST_1; // FIXME: make configurable
        res->requestTimeoutMs = 600 * 1000;
        return res;
    }

    void init()
    {
        if (!diskCache->cacheExists(getUri())) {

            /* Create the bucket if it doesn't already exists. */
            // FIXME: HeadBucket would be more appropriate, but doesn't return
            // an easily parsed 404 message.
            auto res = client->GetBucketLocation(
                Aws::S3::Model::GetBucketLocationRequest().WithBucket(bucketName));

            if (!res.IsSuccess()) {
                if (res.GetError().GetErrorType() != Aws::S3::S3Errors::NO_SUCH_BUCKET)
                    throw Error(format("AWS error checking bucket ‘%s’: %s") % bucketName % res.GetError().GetMessage());

                checkAws(format("AWS error creating bucket ‘%s’") % bucketName,
                    client->CreateBucket(
                        Aws::S3::Model::CreateBucketRequest()
                        .WithBucket(bucketName)
                        .WithCreateBucketConfiguration(
                            Aws::S3::Model::CreateBucketConfiguration()
                            /* .WithLocationConstraint(
                               Aws::S3::Model::BucketLocationConstraint::US) */ )));
            }

            BinaryCacheStore::init();

            diskCache->createCache(getUri());
        }
    }

    const Stats & getS3Stats()
    {
        return stats;
    }

    /* This is a specialisation of isValidPath() that optimistically
       fetches the .narinfo file, rather than first checking for its
       existence via a HEAD request. Since .narinfos are small, doing
       a GET is unlikely to be slower than HEAD. */
    bool isValidPathUncached(const Path & storePath)
    {
        try {
            queryPathInfo(storePath);
            return true;
        } catch (InvalidPath & e) {
            return false;
        }
    }

    bool fileExists(const std::string & path)
    {
        stats.head++;

        auto res = client->HeadObject(
            Aws::S3::Model::HeadObjectRequest()
            .WithBucket(bucketName)
            .WithKey(path));

        if (!res.IsSuccess()) {
            auto & error = res.GetError();
            if (error.GetErrorType() == Aws::S3::S3Errors::UNKNOWN // FIXME
                && error.GetMessage().find("404") != std::string::npos)
                return false;
            throw Error(format("AWS error fetching ‘%s’: %s") % path % error.GetMessage());
        }

        return true;
    }

    void upsertFile(const std::string & path, const std::string & data)
    {
        auto request =
            Aws::S3::Model::PutObjectRequest()
            .WithBucket(bucketName)
            .WithKey(path);

        auto stream = std::make_shared<std::stringstream>(data);

        request.SetBody(stream);

        stats.put++;
        stats.putBytes += data.size();

        auto now1 = std::chrono::steady_clock::now();

        auto result = checkAws(format("AWS error uploading ‘%s’") % path,
            client->PutObject(request));

        auto now2 = std::chrono::steady_clock::now();

        auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();

        printMsg(lvlInfo, format("uploaded ‘s3://%1%/%2%’ (%3% bytes) in %4% ms")
            % bucketName % path % data.size() % duration);

        stats.putTimeMs += duration;
    }

    std::shared_ptr<std::string> getFile(const std::string & path)
    {
        printMsg(lvlDebug, format("fetching ‘s3://%1%/%2%’...") % bucketName % path);

        auto request =
            Aws::S3::Model::GetObjectRequest()
            .WithBucket(bucketName)
            .WithKey(path);

        request.SetResponseStreamFactory([&]() {
            return Aws::New<std::stringstream>("STRINGSTREAM");
        });

        stats.get++;

        try {

            auto now1 = std::chrono::steady_clock::now();

            auto result = checkAws(format("AWS error fetching ‘%s’") % path,
                client->GetObject(request));

            auto now2 = std::chrono::steady_clock::now();

            auto res = dynamic_cast<std::stringstream &>(result.GetBody()).str();

            auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();

            printMsg(lvlTalkative, format("downloaded ‘s3://%1%/%2%’ (%3% bytes) in %4% ms")
                % bucketName % path % res.size() % duration);

            stats.getBytes += res.size();
            stats.getTimeMs += duration;

            return std::make_shared<std::string>(res);

        } catch (S3Error & e) {
            if (e.err == Aws::S3::S3Errors::NO_SUCH_KEY) return 0;
            throw;
        }
    }

};

static RegisterStoreImplementation regStore([](const std::string & uri) -> std::shared_ptr<Store> {
    if (std::string(uri, 0, 5) != "s3://") return 0;
    auto store = std::make_shared<S3BinaryCacheStoreImpl>(std::shared_ptr<Store>(0),
        settings.get("binary-cache-secret-key-file", string("")),
        std::string(uri, 5));
    store->init();
    return store;
});

}