Add support for summary, metadata, and alternatives. (#52)

This change adds support for the following v2 API endpoints
* `/v2/summary`, which returns an aggregate view of the dependency
* `/v2/pkg`, which returns more detailed information about a package
* `/v2/alternatives`, which returns packages which can be used in
  place of the given one

Note: this also contains a very minor breaking change that will impact
existing users; we changed the client constructor ruotines from
returning a pointer-to-struct to returning an interface, which
unfortunately requires users to accomodate their code. Despite being a
breaking change, we won't bump the major version because we consider
this sdk unstable at the moment.

cmd/example/main.go

@@ -0,0 +1,101 @@
+// Copyright 2024 Stacklok, Inc.
+//
+// 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.
+
+//nolint:revive
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"os"
+
+	v2client "github.com/stacklok/trusty-sdk-go/pkg/v2/client"
+	v2types "github.com/stacklok/trusty-sdk-go/pkg/v2/types"
+)
+
+func main() {
+	var endpoint, pname string
+	flag.StringVar(&endpoint, "endpoint", "", "Trusty API endpoint to call")
+	flag.StringVar(&pname, "pname", "", "Package name")
+	flag.Parse()
+
+	ctx := context.Background()
+	client := v2client.New()
+
+	switch endpoint {
+	case "summary":
+		if err := summary(ctx, client, pname); err != nil {
+			fmt.Fprintf(os.Stderr, "error calling endpoint: %s\n", err)
+			os.Exit(1)
+		}
+	case "pkg-meta":
+		if err := pkg(ctx, client, pname); err != nil {
+			fmt.Fprintf(os.Stderr, "error calling endpoint: %s\n", err)
+			os.Exit(1)
+		}
+	case "alternatives":
+		if err := alternatives(ctx, client, pname); err != nil {
+			fmt.Fprintf(os.Stderr, "error calling endpoint: %s\n", err)
+			os.Exit(1)
+		}
+	case "":
+		fmt.Fprintf(os.Stderr, "endpoint is mandatory\n")
+		os.Exit(1)
+	default:
+		fmt.Fprintf(os.Stderr, "invalid method: %s\n", endpoint)
+		os.Exit(1)
+	}
+}
+
+func summary(ctx context.Context, client v2client.Trusty, pname string) error {
+	res, err := client.Summary(ctx, &v2types.Dependency{
+		PackageName: pname,
+	})
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("%+v\n", res)
+	return nil
+}
+
+func pkg(ctx context.Context, client v2client.Trusty, pname string) error {
+	res, err := client.PackageMetadata(ctx, &v2types.Dependency{
+		PackageName: pname,
+	})
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("%+v\n", res)
+	fmt.Printf("STATUS: %+v\n", *res.Status)
+	fmt.Printf("MALICIOUS: %+v\n", res.Malicious)
+	for _, contributor := range res.Contributors {
+		fmt.Printf("CONTRIBUTOR: %+v\n", contributor)
+	}
+	return nil
+}
+
+func alternatives(ctx context.Context, client v2client.Trusty, pname string) error {
+	res, err := client.Alternatives(ctx, &v2types.Dependency{
+		PackageName: pname,
+	})
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("%+v\n", res)
+	return nil
+}

go.mod

@@ -7,6 +7,7 @@ toolchain go1.23.1
 require (
 	github.com/BurntSushi/toml v1.4.0
 	github.com/google/go-github/v66 v66.0.0
+	github.com/google/uuid v1.6.0
 	github.com/package-url/packageurl-go v0.1.3
 	github.com/stretchr/testify v1.9.0
 	golang.org/x/oauth2 v0.24.0

go.sum

@@ -10,6 +10,8 @@ github.com/google/go-github/v66 v66.0.0 h1:ADJsaXj9UotwdgK8/iFZtv7MLc8E8WBl62WLd
 github.com/google/go-github/v66 v66.0.0/go.mod h1:+4SO9Zkuyf8ytMj0csN1NR/5OTR+MfqPp8P8dVlcvY4=
 github.com/google/go-querystring v1.1.0 h1:AnCroh3fv4ZBgVIf1Iwtovgjaw/GiKJo8M8yD/fhyJ8=
 github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17icRSOU623lUBU=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/nozzle/throttler v0.0.0-20180817012639-2ea982251481 h1:Up6+btDp321ZG5/zdSLo48H9Iaq0UQGthrhWC6pCxzE=
 github.com/nozzle/throttler v0.0.0-20180817012639-2ea982251481/go.mod h1:yKZQO8QE2bHlgozqWDiRVqTFlLQSj30K/6SAK8EeYFw=
 github.com/package-url/packageurl-go v0.1.3 h1:4juMED3hHiz0set3Vq3KeQ75KD1avthoXLtmE3I0PLs=