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Reverse retry logic to retry in all but a few cases

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It was getting too much like whac-a-mole listing all the retriable error
conditions, so we now retry by default and list the cases where retrying
is almost certainly hopeless.
This commit is contained in:
Dan Peebles 2017-09-25 12:36:01 -07:00
parent f3e0d46821
commit 476493dbf5
2 changed files with 40 additions and 19 deletions
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4
.gitignore vendored
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@ -99,16 +99,20 @@ perl/Makefile.config
/misc/systemd/nix-daemon.socket
/misc/upstart/nix-daemon.conf
/src/resolve-system-dependencies/resolve-system-dependencies
inst/
*.a
*.o
*.so
*.dylib
*.dll
*.exe
*.dep
*~
*.pc
*.plist
# GNU Global
GPATH

55
src/libstore/download.cc
View file

@ -278,26 +278,43 @@ struct CurlDownloader : public Downloader
callFailure(failure, std::current_exception());
}
} else {
Error err =
(httpStatus == 404 || code == CURLE_FILE_COULDNT_READ_FILE) ? NotFound :
httpStatus == 403 ? Forbidden :
(httpStatus == 408 || httpStatus == 500 || httpStatus == 503
|| httpStatus == 504 || httpStatus == 522 || httpStatus == 524
|| code == CURLE_COULDNT_RESOLVE_HOST
|| code == CURLE_RECV_ERROR
// We treat most errors as transient, but won't retry when hopeless
Error err = Transient;
// this seems to occur occasionally for retriable reasons, and shows up in an error like this:
// curl: (23) Failed writing body (315 != 16366)
|| code == CURLE_WRITE_ERROR
// this is a generic SSL failure that in some cases (e.g., certificate error) is permanent but also appears in transient cases, so we consider it retryable
|| code == CURLE_SSL_CONNECT_ERROR
#if LIBCURL_VERSION_NUM >= 0x073200
|| code == CURLE_HTTP2
|| code == CURLE_HTTP2_STREAM
#endif
) ? Transient :
Misc;
if (httpStatus == 404 || code == CURLE_FILE_COULDNT_READ_FILE) {
// The file is definitely not there
err = NotFound;
} else if (httpStatus == 401 || httpStatus == 403 || httpStatus == 407) {
// Don't retry on authentication/authorization failures
err = Forbidden;
} else if (httpStatus >= 400 && httpStatus < 500 && httpStatus != 408) {
// Most 4xx errors are client errors and are probably not worth retrying:
// * 408 means the server timed out waiting for us, so we try again
err = Misc;
} else if (httpStatus == 501 || httpStatus == 505 || httpStatus == 511) {
// Let's treat most 5xx (server) errors as transient, except for a handful:
// * 501 not implemented
// * 505 http version not supported
// * 511 we're behind a captive portal
err = Misc;
} else {
// Don't bother retrying on certain cURL errors either
switch (code) {
case CURLE_FAILED_INIT:
case CURLE_NOT_BUILT_IN:
case CURLE_REMOTE_ACCESS_DENIED:
case CURLE_FILE_COULDNT_READ_FILE:
case CURLE_FUNCTION_NOT_FOUND:
case CURLE_ABORTED_BY_CALLBACK:
case CURLE_BAD_FUNCTION_ARGUMENT:
case CURLE_INTERFACE_FAILED:
case CURLE_UNKNOWN_OPTION:
err = Misc;
break;
default: // Shut up warnings
break;
}
}
attempt++;