chainfee: simplify WebAPIFeeSource interface

This commit removes the interface methods `GenQueryURL` and
`ParseResponse` so the `WebAPIEstimator` can care less about the
implementation details of this interface.

lnwallet/chainfee/estimator.go

@@ -493,16 +493,6 @@ var _ Estimator = (*BitcoindEstimator)(nil)
 // implementation of this interface in order to allow the WebAPIEstimator to
 // be fully generic in its logic.
 type WebAPIFeeSource interface {
-	// GenQueryURL generates the full query URL. The value returned by this
-	// method should be able to be used directly as a path for an HTTP GET
-	// request.
-	GenQueryURL() string
-
-	// ParseResponse attempts to parse the body of the response generated
-	// by the above query URL. Typically this will be JSON, but the
-	// specifics are left to the WebAPIFeeSource implementation.
-	ParseResponse(r io.Reader) (map[uint32]uint32, error)
-
 	// GetFeeMap will query the web API, parse the response and return a
 	// map of confirmation targets to sat/kw fees.
 	GetFeeMap() (map[uint32]uint32, error)
@@ -517,21 +507,12 @@ type SparseConfFeeSource struct {
 	URL string
 }
 
-// GenQueryURL generates the full query URL. The value returned by this
+// parseResponse attempts to parse the body of the response generated by the
-// method should be able to be used directly as a path for an HTTP GET
-// request.
-//
-// NOTE: Part of the WebAPIFeeSource interface.
-func (s SparseConfFeeSource) GenQueryURL() string {
-	return s.URL
-}
-
-// ParseResponse attempts to parse the body of the response generated by the
 // above query URL. Typically this will be JSON, but the specifics are left to
 // the WebAPIFeeSource implementation.
-//
+func (s SparseConfFeeSource) parseResponse(r io.Reader) (
-// NOTE: Part of the WebAPIFeeSource interface.
+	map[uint32]uint32, error) {
-func (s SparseConfFeeSource) ParseResponse(r io.Reader) (map[uint32]uint32, error) {
+
 	type jsonResp struct {
 		FeeByBlockTarget map[uint32]uint32 `json:"fee_by_block_target"`
 	}
@@ -567,7 +548,7 @@ func (s SparseConfFeeSource) GetFeeMap() (map[uint32]uint32, error) {
 
 	// With the client created, we'll query the API source to fetch the URL
 	// that we should use to query for the fee estimation.
-	targetURL := s.GenQueryURL()
+	targetURL := s.URL
 	resp, err := netClient.Get(targetURL)
 	if err != nil {
 		log.Errorf("unable to query web api for fee response: %v",
@@ -578,7 +559,7 @@ func (s SparseConfFeeSource) GetFeeMap() (map[uint32]uint32, error) {
 
 	// Once we've obtained the response, we'll instruct the WebAPIFeeSource
 	// to parse out the body to obtain our final result.
-	feesByBlockTarget, err := s.ParseResponse(resp.Body)
+	feesByBlockTarget, err := s.parseResponse(resp.Body)
 	if err != nil {
 		log.Errorf("unable to parse fee api response: %v", err)
 

lnwallet/chainfee/estimator_test.go

@@ -3,8 +3,6 @@ package chainfee
 import (
 	"bytes"
 	"encoding/json"
-	"io"
-	"reflect"
 	"testing"
 
 	"github.com/btcsuite/btcd/btcutil"
@@ -16,14 +14,6 @@ type mockSparseConfFeeSource struct {
 	fees map[uint32]uint32
 }
 
-func (e mockSparseConfFeeSource) GenQueryURL() string {
-	return e.url
-}
-
-func (e mockSparseConfFeeSource) ParseResponse(r io.Reader) (map[uint32]uint32, error) {
-	return e.fees, nil
-}
-
 func (e mockSparseConfFeeSource) GetFeeMap() (map[uint32]uint32, error) {
 	return e.fees, nil
 }
@@ -117,10 +107,6 @@ func TestSparseConfFeeSource(t *testing.T) {
 	// Test that GenQueryURL returns the URL as is.
 	url := "test"
 	feeSource := SparseConfFeeSource{URL: url}
-	queryURL := feeSource.GenQueryURL()
-	if queryURL != url {
-		t.Fatalf("expected query URL of %v, got %v", url, queryURL)
-	}
 
 	// Test parsing a properly formatted JSON API response.
 	// First, create the response as a bytes.Reader.
@@ -129,17 +115,17 @@ func TestSparseConfFeeSource(t *testing.T) {
 		2: 42,
 		3: 54321,
 	}
-	testJSON := map[string]map[uint32]uint32{"fee_by_block_target": testFees}
+	testJSON := map[string]map[uint32]uint32{
+		"fee_by_block_target": testFees,
+	}
 	jsonResp, err := json.Marshal(testJSON)
 	require.NoError(t, err, "unable to marshal JSON API response")
 	reader := bytes.NewReader(jsonResp)
 
 	// Finally, ensure the expected map is returned without error.
-	fees, err := feeSource.ParseResponse(reader)
+	fees, err := feeSource.parseResponse(reader)
 	require.NoError(t, err, "unable to parse API response")
-	if !reflect.DeepEqual(fees, testFees) {
+	require.Equal(t, testFees, fees, "unexpected fee map returned")
-		t.Fatalf("expected %v, got %v", testFees, fees)
-	}
 
 	// Test parsing an improperly formatted JSON API response.
 	badFees := map[string]uint32{"hi": 12345, "hello": 42, "satoshi": 54321}
@@ -149,10 +135,8 @@ func TestSparseConfFeeSource(t *testing.T) {
 	reader = bytes.NewReader(jsonResp)
 
 	// Finally, ensure the improperly formatted fees error.
-	_, err = feeSource.ParseResponse(reader)
+	_, err = feeSource.parseResponse(reader)
-	if err == nil {
+	require.Error(t, err, "expected error when parsing bad JSON")
-		t.Fatalf("expected ParseResponse to fail")
-	}
 }
 
 // TestWebAPIFeeEstimator checks that the WebAPIFeeEstimator returns fee rates