storage: add client for /uploads endpoint

Change-Id: Id9eecd9bc5bf7be4ffcdd5a120c7ccc4afe2fb17
Reviewed-on: https://go-review.googlesource.com/36115Reviewed-by: Russ Cox <rsc@golang.org>

storage/client.go

@@ -6,6 +6,7 @@
 package storage
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -111,4 +112,98 @@ func (q *Query) Close() error {
 	return q.err
 }
 
+// UploadInfo represents an upload summary.
+type UploadInfo struct {
+	Count       int
+	UploadID    string
+	LabelValues benchfmt.Labels `json:",omitempty"`
+}
+
+// ListUploads searches for uploads containing results matching the given query string.
+// The query may be empty, in which case all uploads will be returned.
+// extraLabels specifies other labels to be retrieved.
+// If limit is 0, no limit will be provided to the server.
+// The uploads are returned starting with the most recent upload.
+func (c *Client) ListUploads(q string, extraLabels []string, limit int) *UploadList {
+	hc := c.httpClient()
+
+	v := url.Values{"extra_label": extraLabels}
+	if q != "" {
+		v["q"] = []string{q}
+	}
+	if limit != 0 {
+		v["limit"] = []string{fmt.Sprintf("%d", limit)}
+	}
+
+	u := c.BaseURL + "/uploads"
+	if len(v) > 0 {
+		u += "?" + v.Encode()
+	}
+	resp, err := hc.Get(u)
+	if err != nil {
+		return &UploadList{err: err}
+	}
+	if resp.StatusCode != 200 {
+		body, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			return &UploadList{err: err}
+		}
+		return &UploadList{err: fmt.Errorf("%s", body)}
+	}
+	return &UploadList{body: resp.Body, dec: json.NewDecoder(resp.Body)}
+}
+
+// UploadList is the result of ListUploads.
+// Use Next to advance through the rows, making sure to call Close when done:
+//
+//   q := db.ListUploads("key:value")
+//   defer q.Close()
+//   for q.Next() {
+//     id, count := q.Row()
+//     labels := q.LabelValues()
+//     ...
+//   }
+//   err = q.Err() // get any error encountered during iteration
+//   ...
+type UploadList struct {
+	body io.Closer
+	dec  *json.Decoder
+	// from last call to Next
+	ui  UploadInfo
+	err error
+}
+
+// Next prepares the next result for reading with the Result
+// method. It returns false when there are no more results, either by
+// reaching the end of the input or an error.
+func (ul *UploadList) Next() bool {
+	if ul.err != nil {
+		return false
+	}
+	ul.err = ul.dec.Decode(&ul.ui)
+	return ul.err == nil
+}
+
+// Info returns the most recent UploadInfo generated by a call to Next.
+func (ul *UploadList) Info() UploadInfo {
+	return ul.ui
+}
+
+// Err returns the error state of the query.
+func (ul *UploadList) Err() error {
+	if ul.err == io.EOF {
+		return nil
+	}
+	return ul.err
+}
+
+// Close frees resources associated with the query.
+func (ul *UploadList) Close() error {
+	if ul.body != nil {
+		return ul.body.Close()
+		ul.body = nil
+	}
+	return ul.Err()
+}
+
 // TODO(quentin): Move upload code here from cmd/benchsave?

storage/client_test.go

@@ -12,6 +12,7 @@ import (
 	"net/http/httptest"
 	"os"
 	"os/exec"
+	"reflect"
 	"testing"
 
 	"golang.org/x/perf/storage/benchfmt"
@@ -67,6 +68,31 @@ func TestQuery(t *testing.T) {
 	}
 }
 
+func TestListUploads(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if have, want := r.URL.RequestURI(), "/uploads?extra_label=key1&extra_label=key2&limit=10&q=key1%3Avalue+key2%3Avalue"; have != want {
+			t.Errorf("RequestURI = %q, want %q", have, want)
+		}
+		fmt.Fprintf(w, "%s\n", `{"UploadID": "id", "Count": 100, "LabelValues": {"key1": "value"}}`)
+	}))
+	defer ts.Close()
+
+	c := &Client{BaseURL: ts.URL}
+
+	r := c.ListUploads("key1:value key2:value", []string{"key1", "key2"}, 10)
+	defer r.Close()
+
+	if !r.Next() {
+		t.Errorf("Next = false, want true")
+	}
+	if have, want := r.Info(), (UploadInfo{Count: 100, UploadID: "id", LabelValues: benchfmt.Labels{"key1": "value"}}); !reflect.DeepEqual(have, want) {
+		t.Errorf("Info = %#v, want %#v", have, want)
+	}
+	if err := r.Err(); err != nil {
+		t.Fatalf("Err: %v", err)
+	}
+}
+
 // diff returns the output of unified diff on s1 and s2. If the result
 // is non-empty, the strings differ or the diff command failed.
 func diff(s1, s2 string) string {