Add support for a structured URL type. (#400)

* Add support for a structured URL type.

This type can be used to accept `url: http://asdf.com` where in code we
get a `url.URL` to interact with.

* Propagate errors parsing, cast pointer instead of copying.

apis/url.go

@@ -0,0 +1,73 @@
+/*
+Copyright 2019 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package apis
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/url"
+)
+
+// URL is an alias of url.URL.
+// It has custom json marshal methods that enable it to be used in K8s CRDs
+// such that the CRD resource will have the URL but operator code can can work with url.URL struct
+type URL url.URL
+
+// ParseURL attempts to parse the given string as a URL.
+func ParseURL(u string) (*URL, error) {
+	if u == "" {
+		return nil, nil
+	}
+	pu, err := url.Parse(u)
+	if err != nil {
+		return nil, err
+	}
+	return (*URL)(pu), nil
+}
+
+// MarshalJSON implements a custom json marshal method used when this type is
+// marshaled using json.Marshal.
+// json.Marshaler impl
+func (u URL) MarshalJSON() ([]byte, error) {
+	b := fmt.Sprintf("%q", u.String())
+	return []byte(b), nil
+}
+
+// UnmarshalJSON implements the json unmarshal method used when this type is
+// unmarsheled using json.Unmarshal.
+// json.Unmarshaler impl
+func (u *URL) UnmarshalJSON(b []byte) error {
+	var ref string
+	if err := json.Unmarshal(b, &ref); err != nil {
+		return err
+	}
+	r, err := ParseURL(ref)
+	if err != nil {
+		return err
+	}
+	*u = *r
+	return nil
+}
+
+// String returns the full string representation of the URL.
+func (u *URL) String() string {
+	if u == nil {
+		return ""
+	}
+	uu := url.URL(*u)
+	return uu.String()
+}

apis/url_test.go

@@ -0,0 +1,204 @@
+/*
+Copyright 2019 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package apis
+
+import (
+	"net/url"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestParseURL(t *testing.T) {
+	testCases := map[string]struct {
+		t       string
+		want    *URL
+		wantErr bool
+	}{
+		"empty": {
+			want: nil,
+		},
+		"empty string": {
+			t:    "",
+			want: nil,
+		},
+		"invalid format": {
+			t:       "💩://error",
+			want:    nil,
+			wantErr: true,
+		},
+		"relative": {
+			t: "/path/to/something",
+			want: func() *URL {
+				uu, _ := url.Parse("/path/to/something")
+				u := URL(*uu)
+				return &u
+			}(),
+		},
+		"url": {
+			t: "http://path/to/something",
+			want: func() *URL {
+				uu, _ := url.Parse("http://path/to/something")
+				u := URL(*uu)
+				return &u
+			}(),
+		},
+	}
+	for n, tc := range testCases {
+		t.Run(n, func(t *testing.T) {
+
+			got, err := ParseURL(tc.t)
+			if err != nil {
+				if !tc.wantErr {
+					t.Fatalf("ParseURL() = %v", err)
+				}
+				return
+			} else if tc.wantErr {
+				t.Fatalf("ParseURL() = %v, wanted error", got)
+			}
+
+			if diff := cmp.Diff(tc.want, got); diff != "" {
+				t.Errorf("unexpected object (-want, +got) = %v", diff)
+			}
+		})
+	}
+}
+
+func TestJsonMarshalURL(t *testing.T) {
+	testCases := map[string]struct {
+		t    string
+		want []byte
+	}{
+		"empty": {},
+		"empty string": {
+			t: "",
+		},
+		"invalid url": {
+			t:    "not a url",
+			want: []byte(`"not%20a%20url"`),
+		},
+		"relative format": {
+			t:    "/path/to/something",
+			want: []byte(`"/path/to/something"`),
+		},
+	}
+	for n, tc := range testCases {
+		t.Run(n, func(t *testing.T) {
+
+			var got []byte
+			tt, err := ParseURL(tc.t)
+			if err != nil {
+				t.Fatalf("ParseURL() = %v", err)
+			}
+			if tt != nil {
+				got, _ = tt.MarshalJSON()
+			}
+
+			if diff := cmp.Diff(tc.want, got); diff != "" {
+				t.Logf("got: %s", string(got))
+				t.Errorf("unexpected object (-want, +got) = %v", diff)
+			}
+		})
+	}
+}
+
+func TestJsonUnmarshalURL(t *testing.T) {
+	testCases := map[string]struct {
+		b       []byte
+		want    *URL
+		wantErr string
+	}{
+		"empty": {
+			wantErr: "unexpected end of JSON input",
+		},
+		"invalid format": {
+			b:       []byte("%"),
+			wantErr: "invalid character '%' looking for beginning of value",
+		},
+		"relative": {
+			b: []byte(`"/path/to/something"`),
+			want: func() *URL {
+				uu, _ := url.Parse("/path/to/something")
+				u := URL(*uu)
+				return &u
+			}(),
+		},
+		"url": {
+			b: []byte(`"http://path/to/something"`),
+			want: func() *URL {
+				uu, _ := url.Parse("http://path/to/something")
+				u := URL(*uu)
+				return &u
+			}(),
+		},
+	}
+	for n, tc := range testCases {
+		t.Run(n, func(t *testing.T) {
+
+			got := &URL{}
+			err := got.UnmarshalJSON(tc.b)
+
+			if tc.wantErr != "" || err != nil {
+				var gotErr string
+				if err != nil {
+					gotErr = err.Error()
+				}
+				if diff := cmp.Diff(tc.wantErr, gotErr); diff != "" {
+					t.Errorf("unexpected error (-want, +got) = %v", diff)
+				}
+				return
+			}
+
+			if diff := cmp.Diff(tc.want, got); diff != "" {
+				t.Errorf("unexpected object (-want, +got) = %v", diff)
+			}
+		})
+	}
+}
+
+func TestURLString(t *testing.T) {
+	testCases := map[string]struct {
+		t    string
+		want string
+	}{
+		"empty": {
+			want: "",
+		},
+		"relative": {
+			t:    "/path/to/something",
+			want: "/path/to/something",
+		},
+		"url": {
+			t:    "http://path/to/something",
+			want: "http://path/to/something",
+		},
+	}
+	for n, tc := range testCases {
+		t.Run(n, func(t *testing.T) {
+
+			tt, err := ParseURL(tc.t)
+			if err != nil {
+				t.Fatalf("ParseURL() = %v", err)
+			}
+			got := tt.String()
+
+			if diff := cmp.Diff(tc.want, got); diff != "" {
+				t.Logf("got: %s", string(got))
+				t.Errorf("unexpected string (-want, +got) = %v", diff)
+			}
+		})
+	}
+}

apis/zz_generated.deepcopy.go

@@ -20,6 +20,10 @@ limitations under the License.
 
 package apis
 
+import (
+	url "net/url"
+)
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *Condition) DeepCopyInto(out *Condition) {
 	*out = *in
@@ -87,6 +91,27 @@ func (in *FieldError) DeepCopy() *FieldError {
 	return out
 }
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *URL) DeepCopyInto(out *URL) {
+	*out = *in
+	if in.User != nil {
+		in, out := &in.User, &out.User
+		*out = new(url.Userinfo)
+		**out = **in
+	}
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new URL.
+func (in *URL) DeepCopy() *URL {
+	if in == nil {
+		return nil
+	}
+	out := new(URL)
+	in.DeepCopyInto(out)
+	return out
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *VolatileTime) DeepCopyInto(out *VolatileTime) {
 	*out = *in