feat: add tooling

metadata/decode.go

@@ -248,6 +248,7 @@ func mdsParseX509Certificate(value string) (certificate *x509.Certificate, err e
 	return certificate, nil
 }
 
+// DecoderOption is a representation of a function that can set options within a decoder.
 type DecoderOption func(decoder *Decoder) (err error)
 
 // WithIgnoreEntryParsingErrors is a DecoderOption which ignores errors when parsing individual entries. The values for
@@ -260,6 +261,7 @@ func WithIgnoreEntryParsingErrors() DecoderOption {
 	}
 }
 
+// WithRootCertificate overrides the root certificate used to validate the authenticity of the metadata payload.
 func WithRootCertificate(value string) DecoderOption {
 	return func(decoder *Decoder) (err error) {
 		decoder.root = value

metadata/metadata.go

@@ -3,13 +3,41 @@ package metadata
 import (
 	"crypto/x509"
 	"fmt"
+	"net/http"
 	"net/url"
 	"strings"
 	"time"
 
 	"github.com/google/uuid"
 )
 
+// Fetch creates a new HTTP client and gets the production metadata, decodes it, and parses it. This is an
+// instrumentation simplification that makes it easier to either just grab the latest metadata or for implementers to
+// see the rough process of retrieving it to implement any of their own logic.
+func Fetch() (metadata *Metadata, err error) {
+	var (
+		decoder *Decoder
+		payload *MetadataBLOBPayloadJSON
+		res     *http.Response
+	)
+
+	if decoder, err = NewDecoder(); err != nil {
+		return nil, err
+	}
+
+	client := &http.Client{}
+
+	if res, err = client.Get(ProductionMDSURL); err != nil {
+		return nil, err
+	}
+
+	if payload, err = decoder.Decode(res.Body); err != nil {
+		return nil, err
+	}
+
+	return decoder.Parse(payload)
+}
+
 type Metadata struct {
 	Parsed   MetadataBLOBPayload
 	Unparsed []MetadataBLOBPayloadEntryError

metadata/providers/memory/provider.go

@@ -72,3 +72,7 @@ func (p *Provider) ValidateStatusReports(ctx context.Context, reports []metadata
 
 	return metadata.ValidateStatusReports(reports, p.desired, p.undesired)
 }
+
+var (
+	_ metadata.Provider = (*Provider)(nil)
+)