go-vcr
go-vcr
simplifies testing by recording your HTTP interactions and
replaying them in future runs in order to provide fast, deterministic
and accurate testing of your code.
go-vcr
was inspired by the VCR library for Ruby.
Installation
Install go-vcr
by executing the command below:
$ go get github.com/dnaeon/go-vcr/recorder
Usage
Here is a simple example of recording and replaying etcd HTTP interactions.
You can find other examples in the example
directory of this
repository as well.
package main
import (
"log"
"time"
"github.com/dnaeon/go-vcr/recorder"
"github.com/coreos/etcd/client"
"golang.org/x/net/context"
)
func main() {
// Start our recorder
r, err := recorder.New("fixtures/etcd")
if err != nil {
log.Fatal(err)
}
defer r.Stop() // Make sure recorder is stopped once done with it
// Create an etcd configuration using our transport
cfg := client.Config{
Endpoints: []string{"http://127.0.0.1:2379"},
HeaderTimeoutPerRequest: time.Second,
Transport: r, // Inject as transport!
}
// Create an etcd client using the above configuration
c, err := client.New(cfg)
if err != nil {
log.Fatalf("Failed to create etcd client: %s", err)
}
// Get an example key from etcd
etcdKey := "/foo"
kapi := client.NewKeysAPI(c)
resp, err := kapi.Get(context.Background(), etcdKey, nil)
if err != nil {
log.Fatalf("Failed to get etcd key %s: %s", etcdKey, err)
}
log.Printf("Successfully retrieved etcd key %s: %s", etcdKey, resp.Node.Value)
}
Custom Request Matching
During replay mode, You can customize the way incoming requests are matched against the recorded request/response pairs by defining a Matcher function. For example, the following matcher will match on method, URL and body:
r, err := recorder.New("fixtures/matchers")
if err != nil {
log.Fatal(err)
}
defer r.Stop() // Make sure recorder is stopped once done with it
r.SetMatcher(func(r *http.Request, i cassette.Request) bool {
var b bytes.Buffer
if _, err := b.ReadFrom(r.Body); err != nil {
return false
}
r.Body = ioutil.NopCloser(&b)
return cassette.DefaultMatcher(r, i) && (b.String() == "" || b.String() == i.Body)
})
Protecting Sensitive Data
You often provide sensitive data, such as API credentials, when making
requests against a service.
By default, this data will be stored in the recorded data but you probably
don't want this.
Removing or replacing data before it is stored can be done by adding one or
more Filter
s to your Recorder
.
Here is an example that removes the Authorization
header from all requests:
r, err := recorder.New("fixtures/filters")
if err != nil {
log.Fatal(err)
}
defer r.Stop() // Make sure recorder is stopped once done with it
// Add a filter which removes Authorization headers from all requests:
recorder.AddFilter(func(i *cassette.Interaction) error {
delete(i.Request.Header, "Authorization")
return nil
})
License
go-vcr
is Open Source and licensed under the
BSD License