Simplify Weather API source fetching

internal/adapters/weatherapi/client.go

@@ -130,18 +130,32 @@ type bundleBuilder struct {
 	fetchedAt time.Time
 }
 
+type sourceRequest struct {
+	name           string
+	endpoint       string
+	query          queryOptions
+	missingMessage string
+	required       bool
+	decodeLabel    string
+}
+
+type fetchedSource struct {
+	raw    json.RawMessage
+	source weatherdata.Source
+}
+
 func (b *bundleBuilder) fetchObservation(ctx context.Context) error {
-	raw, source, err := b.client.fetch(ctx, "observations", "/observations", queryOptions{precision: true})
+	var observation weatherdata.Observation
-	if err != nil {
+	fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
+		name:           "observations",
+		endpoint:       "/observations",
+		query:          queryOptions{precision: true},
+		missingMessage: "observation data is missing",
+	}, &observation)
+	if err != nil || !ok {
 		return err
 	}
-	if raw == nil {
+	source := fetched.source
-		return b.handleMissing(&source, "observation data is missing", false)
-	}
-	var observation weatherdata.Observation
-	if err := decodeSource(raw, &observation); err != nil {
-		return b.handleMalformed(&source, err, false)
-	}
 	source.IssuedAt = &observation.Timestamp
 	b.bundle.Observation = &observation
 	b.addSource(source)
@@ -149,34 +163,36 @@ func (b *bundleBuilder) fetchObservation(ctx context.Context) error {
 }
 
 func (b *bundleBuilder) fetchCurrent(ctx context.Context) error {
-	raw, source, err := b.client.fetch(ctx, "current", "/conditions/current", queryOptions{precision: true})
+	var current weatherdata.Current
-	if err != nil {
+	fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
+		name:           "current",
+		endpoint:       "/conditions/current",
+		query:          queryOptions{precision: true},
+		missingMessage: "current conditions data is missing",
+	}, &current)
+	if err != nil || !ok {
 		return err
 	}
-	if raw == nil {
+	source := fetched.source
-		return b.handleMissing(&source, "current conditions data is missing", false)
-	}
-	var current weatherdata.Current
-	if err := decodeSource(raw, &current); err != nil {
-		return b.handleMalformed(&source, err, false)
-	}
 	b.bundle.Current = &current
 	b.addSource(source)
 	return nil
 }
 
 func (b *bundleBuilder) fetchHourly(ctx context.Context) error {
-	raw, source, err := b.client.fetch(ctx, "hourly", "/forecast/hourly", queryOptions{precision: true, timezone: true})
+	var hourly weatherdata.ForecastRun
-	if err != nil {
+	fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
+		name:           "hourly",
+		endpoint:       "/forecast/hourly",
+		query:          queryOptions{precision: true, timezone: true},
+		missingMessage: "hourly forecast data is missing",
+		required:       true,
+		decodeLabel:    "hourly forecast",
+	}, &hourly)
+	if err != nil || !ok {
 		return err
 	}
-	if raw == nil {
+	source := fetched.source
-		return b.handleMissing(&source, "hourly forecast data is missing", true)
-	}
-	var hourly weatherdata.ForecastRun
-	if err := decodeSource(raw, &hourly); err != nil {
-		return fmt.Errorf("decode hourly forecast from %s: %w", source.Endpoint, err)
-	}
 	if len(hourly.Periods) == 0 {
 		return fmt.Errorf("hourly forecast from %s contains no periods", source.Endpoint)
 	}
@@ -188,17 +204,17 @@ func (b *bundleBuilder) fetchHourly(ctx context.Context) error {
 }
 
 func (b *bundleBuilder) fetchNarrative(ctx context.Context) error {
-	raw, source, err := b.client.fetch(ctx, "narrative", "/forecast/narrative", queryOptions{precision: true, timezone: true})
+	var narrative weatherdata.ForecastRun
-	if err != nil {
+	fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
+		name:           "narrative",
+		endpoint:       "/forecast/narrative",
+		query:          queryOptions{precision: true, timezone: true},
+		missingMessage: "narrative forecast data is missing",
+	}, &narrative)
+	if err != nil || !ok {
 		return err
 	}
-	if raw == nil {
+	source := fetched.source
-		return b.handleMissing(&source, "narrative forecast data is missing", false)
-	}
-	var narrative weatherdata.ForecastRun
-	if err := decodeSource(raw, &narrative); err != nil {
-		return b.handleMalformed(&source, err, false)
-	}
 	source.IssuedAt = &narrative.IssuedAt
 	source.UpdatedAt = narrative.UpdatedAt
 	b.bundle.Narrative = &narrative
@@ -221,7 +237,7 @@ func (b *bundleBuilder) fetchAlerts(ctx context.Context) error {
 	}
 	var alerts weatherdata.AlertRun
 	if err := decodeSource(raw, &alerts); err != nil {
-		return b.handleMalformed(&source, err, false)
+		return b.handleMalformed(&source, err, sourceRequest{name: "alerts"})
 	}
 	alerts.Raw = append(json.RawMessage(nil), raw...)
 	if alerts.AsOf != nil {
@@ -233,17 +249,17 @@ func (b *bundleBuilder) fetchAlerts(ctx context.Context) error {
 }
 
 func (b *bundleBuilder) fetchDiscussion(ctx context.Context) error {
-	raw, source, err := b.client.fetch(ctx, "discussion", "/discussion", queryOptions{timezone: true})
+	var discussion weatherdata.Discussion
-	if err != nil {
+	fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
+		name:           "discussion",
+		endpoint:       "/discussion",
+		query:          queryOptions{timezone: true},
+		missingMessage: "forecast discussion data is missing",
+	}, &discussion)
+	if err != nil || !ok {
 		return err
 	}
-	if raw == nil {
+	source := fetched.source
-		return b.handleMissing(&source, "forecast discussion data is missing", false)
-	}
-	var discussion weatherdata.Discussion
-	if err := decodeSource(raw, &discussion); err != nil {
-		return b.handleMalformed(&source, err, false)
-	}
 	source.IssuedAt = &discussion.IssuedAt
 	source.UpdatedAt = discussion.UpdatedAt
 	b.bundle.Discussion = &discussion
@@ -252,17 +268,17 @@ func (b *bundleBuilder) fetchDiscussion(ctx context.Context) error {
 }
 
 func (b *bundleBuilder) fetchWeatherStory(ctx context.Context) error {
-	raw, source, err := b.client.fetch(ctx, "weather_story", "/weatherstories/latest", queryOptions{omitUnits: true})
+	var story weatherdata.WeatherStory
-	if err != nil {
+	fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
+		name:           "weather_story",
+		endpoint:       "/weatherstories/latest",
+		query:          queryOptions{omitUnits: true},
+		missingMessage: "NWS weather story data is missing",
+	}, &story)
+	if err != nil || !ok {
 		return err
 	}
-	if raw == nil {
+	source := fetched.source
-		return b.handleMissing(&source, "NWS weather story data is missing", false)
-	}
-	var story weatherdata.WeatherStory
-	if err := decodeSource(raw, &story); err != nil {
-		return b.handleMalformed(&source, err, false)
-	}
 	if !story.StartTime.IsZero() {
 		source.IssuedAt = &story.StartTime
 	}
@@ -273,17 +289,17 @@ func (b *bundleBuilder) fetchWeatherStory(ctx context.Context) error {
 }
 
 func (b *bundleBuilder) fetchSPCConvectiveOutlooks(ctx context.Context) error {
-	raw, source, err := b.client.fetch(ctx, sourceSPCConvectiveOutlooks, convectiveOutlooksEndpoint, queryOptions{timezone: true, omitUnits: true})
+	var run weatherdata.ConvectiveOutlookRun
-	if err != nil {
+	fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
+		name:           sourceSPCConvectiveOutlooks,
+		endpoint:       convectiveOutlooksEndpoint,
+		query:          queryOptions{timezone: true, omitUnits: true},
+		missingMessage: "SPC convective outlook data is missing",
+	}, &run)
+	if err != nil || !ok {
 		return err
 	}
-	if raw == nil {
+	source := fetched.source
-		return b.handleMissing(&source, "SPC convective outlook data is missing", false)
-	}
-	var run weatherdata.ConvectiveOutlookRun
-	if err := decodeSource(raw, &run); err != nil {
-		return b.handleMalformed(&source, err, false)
-	}
 	if run.IssuedAt != nil {
 		source.IssuedAt = run.IssuedAt
 	} else {
@@ -295,6 +311,28 @@ func (b *bundleBuilder) fetchSPCConvectiveOutlooks(ctx context.Context) error {
 	return nil
 }
 
+func (b *bundleBuilder) fetchDecodedSource(ctx context.Context, request sourceRequest, target any) (fetchedSource, bool, error) {
+	fetched, ok, err := b.fetchSource(ctx, request)
+	if err != nil || !ok {
+		return fetchedSource{}, false, err
+	}
+	if err := decodeSource(fetched.raw, target); err != nil {
+		return fetchedSource{}, false, b.handleMalformed(&fetched.source, err, request)
+	}
+	return fetched, true, nil
+}
+
+func (b *bundleBuilder) fetchSource(ctx context.Context, request sourceRequest) (fetchedSource, bool, error) {
+	raw, source, err := b.client.fetch(ctx, request.name, request.endpoint, request.query)
+	if err != nil {
+		return fetchedSource{}, false, err
+	}
+	if raw == nil {
+		return fetchedSource{}, false, b.handleMissing(&source, request.missingMessage, request.required)
+	}
+	return fetchedSource{raw: raw, source: source}, true, nil
+}
+
 func (b *bundleBuilder) handleMissing(source *weatherdata.Source, message string, required bool) error {
 	source.Missing = true
 	if required {
@@ -303,9 +341,13 @@ func (b *bundleBuilder) handleMissing(source *weatherdata.Source, message string
 	return b.applyMissingPolicy(source, "missing_source", message)
 }
 
-func (b *bundleBuilder) handleMalformed(source *weatherdata.Source, err error, required bool) error {
+func (b *bundleBuilder) handleMalformed(source *weatherdata.Source, err error, request sourceRequest) error {
-	if required {
+	if request.required {
-		return fmt.Errorf("decode %s from %s: %w", source.Name, source.Endpoint, err)
+		label := request.name
+		if request.decodeLabel != "" {
+			label = request.decodeLabel
+		}
+		return fmt.Errorf("decode %s from %s: %w", label, source.Endpoint, err)
 	}
 	source.Missing = true
 	return b.applyMissingPolicy(source, "malformed_source", fmt.Sprintf("malformed %s data: %v", source.Name, err))

internal/adapters/weatherapi/client_test.go

@@ -70,6 +70,24 @@ func TestFetchBundleFromFixtures(t *testing.T) {
 	if len(bundle.Warnings) != 0 {
 		t.Fatalf("Warnings length = %d, want no warnings", len(bundle.Warnings))
 	}
+	wantPaths := []string{
+		"/observations",
+		"/conditions/current",
+		"/forecast/hourly",
+		"/forecast/narrative",
+		"/alerts/active",
+		"/discussion",
+		"/weatherstories/latest",
+		convectiveOutlooksEndpoint,
+	}
+	if len(requested) != len(wantPaths) {
+		t.Fatalf("requested paths = %v, want %d source endpoints", requested, len(wantPaths))
+	}
+	for _, want := range wantPaths {
+		if !containsPath(requested, want) {
+			t.Fatalf("requested paths = %v, want %s", requested, want)
+		}
+	}
 	if !containsPath(requested, "/forecast/hourly") || containsPath(requested, "/forecast/hourly/today") {
 		t.Fatalf("requested paths = %v, want full hourly endpoint only", requested)
 	}