c/ooni-probe-cli
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

fix(netxlite): ensure HTTP errors are always wrapped (#584)

Browse Source 
1. introduce implementations of HTTPTransport and HTTPClient
that apply an error wrapping policy using the constructor
for a generic top-level error wrapper

2. make sure we use the implementations in point 1 when we
are constructing HTTPTransport and HTTPClient

3. make sure we apply error wrapping using the constructor for
a generic top-level error wrapper when reading bodies

4. acknowledge that error wrapping would be broken if we do
not return the same classification _and_ operation when we wrap
an already wrapped error, so fix the to code to do that

5. acknowledge that the classifiers already deal with preserving
the error string and explain why this is a quirk and why we
cannot remove it right now and what needs to happen to safely
remove this quirk from the codebase

Closes https://github.com/ooni/probe/issues/1860
This commit is contained in:
Simone Basso 2021-11-06 17:49:58 +01:00 committed by GitHub
parent da34cfe6c9
commit 6a935d5407
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
9 changed files with 217 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
internal/measurex/http.go
View File

@ -244,7 +244,7 @@ var ErrHTTPTooManyRedirects = errors.New("stopped after 10 redirects")
func newHTTPClient(db WritableDB, cookiejar http.CookieJar,
txp HTTPTransport, defaultErr error) HTTPClient {
return &httpClientErrWrapper{&http.Client{
return netxlite.WrapHTTPClient(&http.Client{
Transport: txp,
Jar: cookiejar,
CheckRedirect: func(req *http.Request, via []*http.Request) error {
@ -260,19 +260,7 @@ func newHTTPClient(db WritableDB, cookiejar http.CookieJar,
})
return err
},
}}
}
type httpClientErrWrapper struct {
HTTPClient
}
func (c *httpClientErrWrapper) Do(req *http.Request) (*http.Response, error) {
resp, err := c.HTTPClient.Do(req)
if err != nil {
err = netxlite.NewTopLevelGenericErrWrapper(err)
}
return resp, err
})
}
// NewCookieJar is a convenience factory for creating an http.CookieJar

13
internal/netxlite/classify.go
View File

@ -38,6 +38,8 @@ func ClassifyGenericError(err error) string {
// The list returned here matches the values used by MK unless
// explicitly noted otherwise with a comment.
// QUIRK: we cannot remove this check as long as this function
// is exported and used independently from NewErrWrapper.
var errwrapper *ErrWrapper
if errors.As(err, &errwrapper) {
return errwrapper.Error() // we've already wrapped it
@ -143,6 +145,9 @@ const (
// If this classifier fails, it calls ClassifyGenericError
// and returns to the caller its return value.
func ClassifyQUICHandshakeError(err error) string {
// QUIRK: we cannot remove this check as long as this function
// is exported and used independently from NewErrWrapper.
var errwrapper *ErrWrapper
if errors.As(err, &errwrapper) {
return errwrapper.Error() // we've already wrapped it
@ -257,10 +262,14 @@ var (
// If this classifier fails, it calls ClassifyGenericError and
// returns to the caller its return value.
func ClassifyResolverError(err error) string {
// QUIRK: we cannot remove this check as long as this function
// is exported and used independently from NewErrWrapper.
var errwrapper *ErrWrapper
if errors.As(err, &errwrapper) {
return errwrapper.Error() // we've already wrapped it
}
if errors.Is(err, ErrDNSBogon) {
return FailureDNSBogonError // not in MK
}
@ -281,10 +290,14 @@ func ClassifyResolverError(err error) string {
// If this classifier fails, it calls ClassifyGenericError and
// returns to the caller its return value.
func ClassifyTLSHandshakeError(err error) string {
// QUIRK: we cannot remove this check as long as this function
// is exported and used independently from NewErrWrapper.
var errwrapper *ErrWrapper
if errors.As(err, &errwrapper) {
return errwrapper.Error() // we've already wrapped it
}
var x509HostnameError x509.HostnameError
if errors.As(err, &x509HostnameError) {
// Test case: https://wrong.host.badssl.com/

6
internal/netxlite/dnsoverhttps.go
View File

@ -10,12 +10,6 @@ import (
"github.com/ooni/probe-cli/v3/internal/engine/httpheader"
)
// HTTPClient is an http.Client-like interface.
type HTTPClient interface {
Do(req *http.Request) (*http.Response, error)
CloseIdleConnections()
}
// DNSOverHTTPS is a DNS-over-HTTPS DNSTransport.
type DNSOverHTTPS struct {
// Client is the MANDATORY http client to use.

21
internal/netxlite/errwrapper.go
View File

@ -1,6 +1,9 @@
package netxlite
import "encoding/json"
import (
"encoding/json"
"errors"
)
// ErrWrapper is our error wrapper for Go errors. The key objective of
// this structure is to properly set Failure, which is also returned by
@ -78,7 +81,19 @@ type Classifier func(err error) string
//
// This function panics if classifier is nil, or operation
// is the empty string or error is nil.
//
// If the err argument has already been classified, the returned
// error wrapper will use the same classification string and
// failed operation of the original wrapped error.
func NewErrWrapper(c Classifier, op string, err error) *ErrWrapper {
var wrapper *ErrWrapper
if errors.As(err, &wrapper) {
return &ErrWrapper{
Failure: wrapper.Failure,
Operation: wrapper.Operation,
WrappedErr: err,
}
}
if c == nil {
panic("nil classifier")
}
@ -97,6 +112,10 @@ func NewErrWrapper(c Classifier, op string, err error) *ErrWrapper {
// NewTopLevelGenericErrWrapper wraps an error occurring at top
// level using ClassifyGenericError as classifier.
//
// If the err argument has already been classified, the returned
// error wrapper will use the same classification string and
// failed operation of the original error.
func NewTopLevelGenericErrWrapper(err error) *ErrWrapper {
return NewErrWrapper(ClassifyGenericError, TopLevelOperation, err)
}

17
internal/netxlite/errwrapper_test.go
View File

@ -3,6 +3,7 @@ package netxlite
import (
"encoding/json"
"errors"
"fmt"
"io"
"testing"
@ -101,6 +102,22 @@ func TestNewErrWrapper(t *testing.T) {
t.Fatal("unexpected WrappedErr")
}
})
t.Run("when the underlying error is already a wrapped error", func(t *testing.T) {
ew := NewErrWrapper(classifySyscallError, ReadOperation, ECONNRESET)
var err1 error = ew
err2 := fmt.Errorf("cannot read: %w", err1)
ew2 := NewErrWrapper(ClassifyGenericError, TopLevelOperation, err2)
if ew2.Failure != ew.Failure {
t.Fatal("not the same failure")
}
if ew2.Operation != ew.Operation {
t.Fatal("not the same operation")
}
if ew2.WrappedErr != err2 {
t.Fatal("invalid underlying error")
}
})
}
func TestNewTopLevelGenericErrWrapper(t *testing.T) {

41
internal/netxlite/http.go
View File

@ -19,6 +19,19 @@ type HTTPTransport interface {
CloseIdleConnections()
}
// httpTransportErrWrapper is an HTTPTransport with error wrapping.
type httpTransportErrWrapper struct {
HTTPTransport
}
func (txp *httpTransportErrWrapper) RoundTrip(req *http.Request) (*http.Response, error) {
resp, err := txp.HTTPTransport.RoundTrip(req)
if err != nil {
return nil, NewTopLevelGenericErrWrapper(err)
}
return resp, nil
}
// httpTransportLogger is an HTTPTransport with logging.
type httpTransportLogger struct {
// HTTPTransport is the underlying HTTP transport.
@ -141,12 +154,13 @@ func NewOOHTTPBaseTransport(dialer Dialer, tlsDialer TLSDialer) HTTPTransport {
}
}
// WrapHTTPTransport creates an HTTPTransport using the given logger.
// WrapHTTPTransport creates an HTTPTransport using the given logger
// and guarantees that returned errors are wrapped.
//
// This is a low level factory. Consider not using it directly.
func WrapHTTPTransport(logger Logger, txp HTTPTransport) HTTPTransport {
return &httpTransportLogger{
HTTPTransport: txp,
HTTPTransport: &httpTransportErrWrapper{txp},
Logger: logger,
}
}
@ -250,3 +264,26 @@ func NewHTTPTransportStdlib(logger Logger) HTTPTransport {
tlsDialer := NewTLSDialer(dialer, NewTLSHandshakerStdlib(logger))
return NewHTTPTransport(logger, dialer, tlsDialer)
}
// HTTPClient is an http.Client-like interface.
type HTTPClient interface {
Do(req *http.Request) (*http.Response, error)
CloseIdleConnections()
}
// WrapHTTPClient wraps an HTTP client to add error wrapping capabilities.
func WrapHTTPClient(clnt HTTPClient) HTTPClient {
return &httpClientErrWrapper{clnt}
}
type httpClientErrWrapper struct {
HTTPClient
}
func (c *httpClientErrWrapper) Do(req *http.Request) (*http.Response, error) {
resp, err := c.HTTPClient.Do(req)
if err != nil {
return nil, NewTopLevelGenericErrWrapper(err)
}
return resp, nil
}

99
internal/netxlite/http_test.go
View File

@ -16,6 +16,49 @@ import (
"github.com/ooni/probe-cli/v3/internal/netxlite/mocks"
)
func TestHTTPTransportErrWrapper(t *testing.T) {
t.Run("RoundTrip", func(t *testing.T) {
t.Run("with failure", func(t *testing.T) {
txp := &httpTransportErrWrapper{
HTTPTransport: &mocks.HTTPTransport{
MockRoundTrip: func(req *http.Request) (*http.Response, error) {
return nil, io.EOF
},
},
}
resp, err := txp.RoundTrip(&http.Request{})
var errWrapper *ErrWrapper
if !errors.As(err, &errWrapper) {
t.Fatal("the returned error is not an ErrWrapper")
}
if errWrapper.Failure != FailureEOFError {
t.Fatal("unexpected failure", errWrapper.Failure)
}
if resp != nil {
t.Fatal("expected nil response")
}
})
t.Run("with success", func(t *testing.T) {
expect := &http.Response{}
txp := &httpTransportErrWrapper{
HTTPTransport: &mocks.HTTPTransport{
MockRoundTrip: func(req *http.Request) (*http.Response, error) {
return expect, nil
},
},
}
resp, err := txp.RoundTrip(&http.Request{})
if err != nil {
t.Fatal(err)
}
if resp != expect {
t.Fatal("not the expected response")
}
})
})
}
func TestHTTPTransportLogger(t *testing.T) {
t.Run("RoundTrip", func(t *testing.T) {
t.Run("with failure", func(t *testing.T) {
@ -198,7 +241,8 @@ func TestNewHTTPTransport(t *testing.T) {
if logger.Logger != log.Log {
t.Fatal("invalid logger")
}
connectionsCloser := logger.HTTPTransport.(*httpTransportConnectionsCloser)
errWrapper := logger.HTTPTransport.(*httpTransportErrWrapper)
connectionsCloser := errWrapper.HTTPTransport.(*httpTransportConnectionsCloser)
withReadTimeout := connectionsCloser.Dialer.(*httpDialerWithReadTimeout)
if withReadTimeout.Dialer != d {
t.Fatal("invalid dialer")
@ -412,3 +456,56 @@ func TestNewHTTPTransportStdlib(t *testing.T) {
}
txp.CloseIdleConnections()
}
func TestHTTPClientErrWrapper(t *testing.T) {
t.Run("Do", func(t *testing.T) {
t.Run("with failure", func(t *testing.T) {
clnt := &httpClientErrWrapper{
HTTPClient: &mocks.HTTPClient{
MockDo: func(req *http.Request) (*http.Response, error) {
return nil, io.EOF
},
},
}
resp, err := clnt.Do(&http.Request{})
var errWrapper *ErrWrapper
if !errors.As(err, &errWrapper) {
t.Fatal("the returned error is not an ErrWrapper")
}
if errWrapper.Failure != FailureEOFError {
t.Fatal("unexpected failure", errWrapper.Failure)
}
if resp != nil {
t.Fatal("expected nil response")
}
})
t.Run("with success", func(t *testing.T) {
expect := &http.Response{}
clnt := &httpClientErrWrapper{
HTTPClient: &mocks.HTTPClient{
MockDo: func(req *http.Request) (*http.Response, error) {
return expect, nil
},
},
}
resp, err := clnt.Do(&http.Request{})
if err != nil {
t.Fatal(err)
}
if resp != expect {
t.Fatal("not the expected response")
}
})
})
}
func TestWrapHTTPClient(t *testing.T) {
origClient := &http.Client{}
wrapped := WrapHTTPClient(origClient)
errWrapper := wrapped.(*httpClientErrWrapper)
innerClient := errWrapper.HTTPClient.(*http.Client)
if innerClient != origClient {
t.Fatal("not the inner client we expected")
}
}

8
internal/netxlite/iox.go
View File

@ -27,9 +27,9 @@ func ReadAllContext(ctx context.Context, r io.Reader) ([]byte, error) {
case data := <-datach:
return data, nil
case <-ctx.Done():
return nil, ctx.Err()
return nil, NewTopLevelGenericErrWrapper(ctx.Err())
case err := <-errch:
return nil, err
return nil, NewTopLevelGenericErrWrapper(err)
}
}
@ -51,8 +51,8 @@ func CopyContext(ctx context.Context, dst io.Writer, src io.Reader) (int64, erro
case count := <-countch:
return count, nil
case <-ctx.Done():
return 0, ctx.Err()
return 0, NewTopLevelGenericErrWrapper(ctx.Err())
case err := <-errch:
return 0, err
return 0, NewTopLevelGenericErrWrapper(err)
}
}

24
internal/netxlite/iox_test.go
View File

@ -36,6 +36,10 @@ func TestReadAllContext(t *testing.T) {
if !errors.Is(err, expected) {
t.Fatal("not the error we expected", err)
}
var errWrapper *ErrWrapper
if !errors.As(err, &errWrapper) {
t.Fatal("the returned error is not wrapped")
}
if len(out) != 0 {
t.Fatal("not the expected number of bytes")
}
@ -65,6 +69,10 @@ func TestReadAllContext(t *testing.T) {
if !errors.Is(err, context.Canceled) {
t.Fatal("not the error we expected", err)
}
var errWrapper *ErrWrapper
if !errors.As(err, &errWrapper) {
t.Fatal("the returned error is not wrapped")
}
if len(out) != 0 {
t.Fatal("not the expected number of bytes")
}
@ -90,6 +98,10 @@ func TestReadAllContext(t *testing.T) {
if !errors.Is(err, context.Canceled) {
t.Fatal("not the error we expected", err)
}
var errWrapper *ErrWrapper
if !errors.As(err, &errWrapper) {
t.Fatal("the returned error is not wrapped")
}
if len(out) != 0 {
t.Fatal("not the expected number of bytes")
}
@ -123,6 +135,10 @@ func TestCopyContext(t *testing.T) {
if !errors.Is(err, expected) {
t.Fatal("not the error we expected", err)
}
var errWrapper *ErrWrapper
if !errors.As(err, &errWrapper) {
t.Fatal("the returned error is not wrapped")
}
if out != 0 {
t.Fatal("not the expected number of bytes")
}
@ -152,6 +168,10 @@ func TestCopyContext(t *testing.T) {
if !errors.Is(err, context.Canceled) {
t.Fatal("not the error we expected", err)
}
var errWrapper *ErrWrapper
if !errors.As(err, &errWrapper) {
t.Fatal("the returned error is not wrapped")
}
if out != 0 {
t.Fatal("not the expected number of bytes")
}
@ -177,6 +197,10 @@ func TestCopyContext(t *testing.T) {
if !errors.Is(err, context.Canceled) {
t.Fatal("not the error we expected", err)
}
var errWrapper *ErrWrapper
if !errors.As(err, &errWrapper) {
t.Fatal("the returned error is not wrapped")
}
if out != 0 {
t.Fatal("not the expected number of bytes")
}