maurice/snix
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

HttpBinaryCacheStore: Retry on transient HTTP errors

Browse source 
This makes us more robust against 500 errors from CloudFront or S3
(assuming the 500 error isn't cached by CloudFront...).
This commit is contained in:
Eelco Dolstra 2016-08-10 16:06:33 +02:00
parent 9204ea7294
commit 66adbdfd97
3 changed files with 34 additions and 14 deletions
Download patch file Download diff file Expand all files Collapse all files

35
src/libstore/download.cc
View file

@ -8,6 +8,7 @@
#include <curl/curl.h>
#include <iostream>
#include <thread>
namespace nix {
@ -194,7 +195,11 @@ struct CurlDownloader : public Downloader
if (res != CURLE_OK) {
Error err =
httpStatus == 404 ? NotFound :
httpStatus == 403 ? Forbidden : Misc;
httpStatus == 403 ? Forbidden :
(httpStatus == 408 || httpStatus == 500 || httpStatus == 503
|| httpStatus == 504 || httpStatus == 522 || httpStatus == 524
|| res == CURLE_COULDNT_RESOLVE_HOST) ? Transient :
Misc;
if (res == CURLE_HTTP_RETURNED_ERROR && httpStatus != -1)
throw DownloadError(err, format("unable to download ‘%s’: HTTP error %d")
% url % httpStatus);
@ -210,14 +215,26 @@ struct CurlDownloader : public Downloader
DownloadResult download(string url, const DownloadOptions & options) override
{
DownloadResult res;
if (fetch(resolveUri(url), options)) {
res.cached = false;
res.data = data;
} else
res.cached = true;
res.etag = etag;
return res;
size_t attempt = 0;
while (true) {
try {
DownloadResult res;
if (fetch(resolveUri(url), options)) {
res.cached = false;
res.data = data;
} else
res.cached = true;
res.etag = etag;
return res;
} catch (DownloadError & e) {
attempt++;
if (e.error != Transient || attempt >= options.tries) throw;
auto ms = 25 * (1 << (attempt - 1));
printMsg(lvlError, format("warning: %s; retrying in %d ms") % e.what() % ms);
std::this_thread::sleep_for(std::chrono::milliseconds(ms));
}
}
}
};