Fetch independent weather sources concurrently

This commit is contained in:
2026-08-13 03:45:55 +00:00
parent e6450138c2
commit 0516ee148d
4 changed files with 317 additions and 132 deletions

View File

@@ -28,7 +28,10 @@ fetch before source requests begin.
The adapter makes one source request for each endpoint, subject to retry on
transient failures. A successful readiness request supplies the current
conditions source response.
conditions source response. The remaining independent source requests run
concurrently, then their results are processed in the source order shown below.
This keeps source provenance, missing-source policy, and surfaced errors
deterministic regardless of response order.
| Source | Endpoint | Query parameters | Availability |
| --- | --- | --- | --- |

View File

@@ -15,6 +15,11 @@ The adapter's successful readiness request for current conditions is reused as
that normalized source; collection does not trigger a second identical current
conditions request.
After readiness succeeds, the adapter obtains the other independent source
responses concurrently. It merges their normalized results in the established
source order, so provenance, warnings, and source-local failures remain
deterministic. Cancellation remains authoritative for every in-flight request.
The package wraps adapter construction failures, including an invalid Weather
API base URL, as weather-collection setup errors and fetch failures as
bundle-collection errors. It does not retry, persist, select reports, derive

View File

@@ -15,6 +15,7 @@ import (
"path"
"strconv"
"strings"
"sync"
"time"
"gitea.maximumdirect.net/eric/weatherreporter/internal/config"
@@ -121,43 +122,25 @@ func (c *Client) FetchBundle(ctx context.Context) (*weatherdata.Bundle, error) {
fetchedAt := c.now()
builder := bundleBuilder{
client: c,
bundle: &weatherdata.Bundle{FetchedAt: fetchedAt},
fetchedAt: fetchedAt,
client: c,
bundle: &weatherdata.Bundle{FetchedAt: fetchedAt},
}
if err := builder.fetchObservation(ctx); err != nil {
return nil, err
}
if err := builder.fetchCurrent(ctx, warmup); err != nil {
return nil, err
}
if err := builder.fetchHourly(ctx); err != nil {
return nil, err
}
if err := builder.fetchNarrative(ctx); err != nil {
return nil, err
}
if err := builder.fetchAlerts(ctx); err != nil {
return nil, err
}
if err := builder.fetchDiscussion(ctx); err != nil {
return nil, err
}
if err := builder.fetchWeatherStory(ctx); err != nil {
return nil, err
}
if err := builder.fetchSPCConvectiveOutlooks(ctx); err != nil {
return nil, err
for _, acquired := range builder.acquireSources(ctx, warmup) {
if err := ctx.Err(); err != nil {
return nil, fmt.Errorf("fetch weather API sources: %w", err)
}
if err := builder.mergeSource(acquired); err != nil {
return nil, err
}
}
return builder.bundle, nil
}
type bundleBuilder struct {
client *Client
bundle *weatherdata.Bundle
fetchedAt time.Time
client *Client
bundle *weatherdata.Bundle
}
type sourceRequest struct {
@@ -181,14 +164,74 @@ type warmupResponse struct {
fetchedAt time.Time
}
func (b *bundleBuilder) fetchObservation(ctx context.Context) error {
type sourceAcquisition struct {
request sourceRequest
fetched fetchedSource
err error
warmup warmupResponse
usesWarmup bool
}
func (b *bundleBuilder) acquireSources(ctx context.Context, warmup warmupResponse) []sourceAcquisition {
sources := []sourceAcquisition{
{request: sourceRequest{name: config.MissingSourceObservations, endpoint: "/observations", query: queryOptions{precision: true}, missingMessage: "observation data is missing"}},
{request: currentConditionsRequest()},
{request: sourceRequest{name: "hourly", endpoint: "/forecast/hourly", query: queryOptions{precision: true, timezone: true}, missingMessage: "hourly forecast data is missing", required: true, decodeLabel: "hourly forecast"}},
{request: sourceRequest{name: config.MissingSourceNarrative, endpoint: "/forecast/narrative", query: queryOptions{precision: true, timezone: true}, missingMessage: "narrative forecast data is missing"}},
{request: sourceRequest{name: config.MissingSourceAlerts, endpoint: "/alerts/active", query: queryOptions{allowNull: true}, missingMessage: "active alerts data is missing"}},
{request: sourceRequest{name: config.MissingSourceDiscussion, endpoint: "/discussion", query: queryOptions{timezone: true}, missingMessage: "forecast discussion data is missing"}},
{request: sourceRequest{name: config.MissingSourceWeatherStory, endpoint: "/weatherstories/latest", query: queryOptions{omitUnits: true}, missingMessage: "NWS weather story data is missing"}},
{request: sourceRequest{name: sourceSPCConvectiveOutlooks, endpoint: convectiveOutlooksEndpoint, query: queryOptions{timezone: true, omitUnits: true}, missingMessage: "SPC convective outlook data is missing"}},
}
if warmup.endpoint == currentConditionsEndpoint {
sources[1].warmup = warmup
sources[1].usesWarmup = true
}
var group sync.WaitGroup
for i := range sources {
if sources[i].usesWarmup {
continue
}
group.Add(1)
go func(index int) {
defer group.Done()
request := sources[index].request
raw, source, err := b.client.fetch(ctx, request.name, request.endpoint, request.query)
sources[index].fetched = fetchedSource{raw: raw, source: source}
sources[index].err = err
}(i)
}
group.Wait()
return sources
}
func (b *bundleBuilder) mergeSource(acquired sourceAcquisition) error {
switch acquired.request.name {
case config.MissingSourceObservations:
return b.fetchObservation(acquired)
case config.MissingSourceCurrent:
return b.fetchCurrent(acquired)
case "hourly":
return b.fetchHourly(acquired)
case config.MissingSourceNarrative:
return b.fetchNarrative(acquired)
case config.MissingSourceAlerts:
return b.fetchAlerts(acquired)
case config.MissingSourceDiscussion:
return b.fetchDiscussion(acquired)
case config.MissingSourceWeatherStory:
return b.fetchWeatherStory(acquired)
case sourceSPCConvectiveOutlooks:
return b.fetchSPCConvectiveOutlooks(acquired)
default:
return fmt.Errorf("merge unknown weather source %q", acquired.request.name)
}
}
func (b *bundleBuilder) fetchObservation(acquired sourceAcquisition) error {
var observation weatherdata.Observation
fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
name: config.MissingSourceObservations,
endpoint: "/observations",
query: queryOptions{precision: true},
missingMessage: "observation data is missing",
}, &observation)
fetched, ok, err := b.fetchDecodedSource(acquired, &observation)
if err != nil || !ok {
return err
}
@@ -208,19 +251,9 @@ func currentConditionsRequest() sourceRequest {
}
}
func (b *bundleBuilder) fetchCurrent(ctx context.Context, warmup warmupResponse) error {
func (b *bundleBuilder) fetchCurrent(acquired sourceAcquisition) error {
var current weatherdata.Current
request := currentConditionsRequest()
var (
fetched fetchedSource
ok bool
err error
)
if warmup.endpoint == request.endpoint {
fetched, ok, err = b.fetchWarmupSource(warmup, request, &current)
} else {
fetched, ok, err = b.fetchDecodedSource(ctx, request, &current)
}
fetched, ok, err := b.fetchDecodedSource(acquired, &current)
if err != nil || !ok {
return err
}
@@ -230,16 +263,9 @@ func (b *bundleBuilder) fetchCurrent(ctx context.Context, warmup warmupResponse)
return nil
}
func (b *bundleBuilder) fetchHourly(ctx context.Context) error {
func (b *bundleBuilder) fetchHourly(acquired sourceAcquisition) error {
var hourly weatherdata.ForecastRun
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)
fetched, ok, err := b.fetchDecodedSource(acquired, &hourly)
if err != nil || !ok {
return err
}
@@ -262,14 +288,9 @@ func (b *bundleBuilder) fetchHourly(ctx context.Context) error {
return nil
}
func (b *bundleBuilder) fetchNarrative(ctx context.Context) error {
func (b *bundleBuilder) fetchNarrative(acquired sourceAcquisition) error {
var narrative weatherdata.ForecastRun
fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
name: config.MissingSourceNarrative,
endpoint: "/forecast/narrative",
query: queryOptions{precision: true, timezone: true},
missingMessage: "narrative forecast data is missing",
}, &narrative)
fetched, ok, err := b.fetchDecodedSource(acquired, &narrative)
if err != nil || !ok {
return err
}
@@ -281,14 +302,12 @@ func (b *bundleBuilder) fetchNarrative(ctx context.Context) error {
return nil
}
func (b *bundleBuilder) fetchAlerts(ctx context.Context) error {
raw, source, err := b.client.fetch(ctx, config.MissingSourceAlerts, "/alerts/active", queryOptions{allowNull: true})
if err != nil {
func (b *bundleBuilder) fetchAlerts(acquired sourceAcquisition) error {
fetched, ok, err := b.fetchSource(acquired)
if err != nil || !ok {
return err
}
if raw == nil {
return b.handleMissing(&source, "active alerts data is missing", false)
}
raw, source := fetched.raw, fetched.source
if isJSONNull(raw) {
b.bundle.Alerts = &weatherdata.AlertRun{Raw: append(json.RawMessage(nil), raw...)}
b.addSource(source)
@@ -296,7 +315,7 @@ func (b *bundleBuilder) fetchAlerts(ctx context.Context) error {
}
var alerts weatherdata.AlertRun
if err := decodeSource(raw, &alerts); err != nil {
return b.handleMalformed(&source, err, sourceRequest{name: config.MissingSourceAlerts})
return b.handleMalformed(&source, err, acquired.request)
}
alerts.Raw = append(json.RawMessage(nil), raw...)
if alerts.AsOf != nil {
@@ -307,14 +326,9 @@ func (b *bundleBuilder) fetchAlerts(ctx context.Context) error {
return nil
}
func (b *bundleBuilder) fetchDiscussion(ctx context.Context) error {
func (b *bundleBuilder) fetchDiscussion(acquired sourceAcquisition) error {
var discussion weatherdata.Discussion
fetched, ok, err := b.fetchDecodedSource(ctx, sourceRequest{
name: config.MissingSourceDiscussion,
endpoint: "/discussion",
query: queryOptions{timezone: true},
missingMessage: "forecast discussion data is missing",
}, &discussion)
fetched, ok, err := b.fetchDecodedSource(acquired, &discussion)
if err != nil || !ok {
return err
}
@@ -326,21 +340,15 @@ func (b *bundleBuilder) fetchDiscussion(ctx context.Context) error {
return nil
}
func (b *bundleBuilder) fetchWeatherStory(ctx context.Context) error {
func (b *bundleBuilder) fetchWeatherStory(acquired sourceAcquisition) error {
var story weatherdata.WeatherStory
request := sourceRequest{
name: config.MissingSourceWeatherStory,
endpoint: "/weatherstories/latest",
query: queryOptions{omitUnits: true},
missingMessage: "NWS weather story data is missing",
}
fetched, ok, err := b.fetchDecodedSource(ctx, request, &story)
fetched, ok, err := b.fetchDecodedSource(acquired, &story)
if err != nil || !ok {
return err
}
source := fetched.source
if !story.HasUsableContent() {
return b.handleMalformed(&source, fmt.Errorf("weather story has no usable content"), request)
return b.handleMalformed(&source, fmt.Errorf("weather story has no usable content"), acquired.request)
}
if !story.StartTime.IsZero() {
source.IssuedAt = &story.StartTime
@@ -351,14 +359,9 @@ func (b *bundleBuilder) fetchWeatherStory(ctx context.Context) error {
return nil
}
func (b *bundleBuilder) fetchSPCConvectiveOutlooks(ctx context.Context) error {
func (b *bundleBuilder) fetchSPCConvectiveOutlooks(acquired sourceAcquisition) error {
var run weatherdata.ConvectiveOutlookRun
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)
fetched, ok, err := b.fetchDecodedSource(acquired, &run)
if err != nil || !ok {
return err
}
@@ -374,23 +377,12 @@ 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)
func (b *bundleBuilder) fetchDecodedSource(acquired sourceAcquisition, target any) (fetchedSource, bool, error) {
fetched, ok, err := b.fetchSource(acquired)
if err != nil || !ok {
return fetchedSource{}, false, err
}
return b.decodeFetchedSource(fetched, request, target)
}
func (b *bundleBuilder) fetchWarmupSource(warmup warmupResponse, request sourceRequest, target any) (fetchedSource, bool, error) {
raw, source, err := b.client.decodeSourceResponse(request.name, request.endpoint, request.query, warmup.requestURL, warmup.body, warmup.fetchedAt)
if err != nil {
return fetchedSource{}, false, err
}
if raw == nil {
return fetchedSource{}, false, b.handleMissing(&source, request.missingMessage, request.required)
}
return b.decodeFetchedSource(fetchedSource{raw: raw, source: source}, request, target)
return b.decodeFetchedSource(fetched, acquired.request, target)
}
func (b *bundleBuilder) decodeFetchedSource(fetched fetchedSource, request sourceRequest, target any) (fetchedSource, bool, error) {
@@ -400,15 +392,20 @@ func (b *bundleBuilder) decodeFetchedSource(fetched fetchedSource, request sourc
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
func (b *bundleBuilder) fetchSource(acquired sourceAcquisition) (fetchedSource, bool, error) {
if acquired.usesWarmup {
raw, source, err := b.client.decodeSourceResponse(acquired.request.name, acquired.request.endpoint, acquired.request.query, acquired.warmup.requestURL, acquired.warmup.body, acquired.warmup.fetchedAt)
if err != nil {
return fetchedSource{}, false, err
}
acquired.fetched = fetchedSource{raw: raw, source: source}
} else if acquired.err != nil {
return fetchedSource{}, false, acquired.err
}
if raw == nil {
return fetchedSource{}, false, b.handleMissing(&source, request.missingMessage, request.required)
if acquired.fetched.raw == nil {
return fetchedSource{}, false, b.handleMissing(&acquired.fetched.source, acquired.request.missingMessage, acquired.request.required)
}
return fetchedSource{raw: raw, source: source}, true, nil
return acquired.fetched, true, nil
}
func (b *bundleBuilder) handleMissing(source *weatherdata.Source, message string, required bool) error {

View File

@@ -9,6 +9,7 @@ import (
"os"
"path/filepath"
"strings"
"sync"
"testing"
"time"
@@ -115,6 +116,175 @@ func TestFetchBundleFromFixtures(t *testing.T) {
}
}
func TestFetchBundleMergesConcurrentSourcesInSourceOrder(t *testing.T) {
paths := []string{
"/observations",
"/forecast/hourly",
"/forecast/narrative",
"/alerts/active",
"/discussion",
"/weatherstories/latest",
convectiveOutlooksEndpoint,
}
started := make(chan string, len(paths))
release := make(map[string]chan struct{}, len(paths))
for _, path := range paths {
release[path] = make(chan struct{})
}
var releaseOnce sync.Once
releaseAll := func() {
releaseOnce.Do(func() {
for i := len(paths) - 1; i >= 0; i-- {
close(release[paths[i]])
}
})
}
t.Cleanup(releaseAll)
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == currentConditionsEndpoint {
if !serveWeatherFixture(w, r) {
http.NotFound(w, r)
}
return
}
ready, ok := release[r.URL.Path]
if !ok {
http.NotFound(w, r)
return
}
started <- r.URL.Path
<-ready
if !serveWeatherFixture(w, r) {
http.NotFound(w, r)
}
}))
defer server.Close()
client := newTestClient(t, server.URL+"/", nil)
type fetchResult struct {
bundle *weatherdata.Bundle
err error
}
result := make(chan fetchResult, 1)
go func() {
bundle, err := client.FetchBundle(context.Background())
result <- fetchResult{bundle: bundle, err: err}
}()
seen := make(map[string]bool, len(paths))
for range paths {
select {
case path := <-started:
seen[path] = true
case <-time.After(time.Second):
t.Fatalf("independent requests started = %v, want %v", seen, paths)
}
}
releaseAll()
select {
case got := <-result:
if got.err != nil {
t.Fatalf("FetchBundle() error = %v", got.err)
}
wantSources := []string{
config.MissingSourceObservations,
config.MissingSourceCurrent,
"hourly",
config.MissingSourceNarrative,
config.MissingSourceAlerts,
config.MissingSourceDiscussion,
config.MissingSourceWeatherStory,
sourceSPCConvectiveOutlooks,
}
gotSources := make([]string, 0, len(got.bundle.Sources))
for _, source := range got.bundle.Sources {
gotSources = append(gotSources, source.Name)
}
if strings.Join(gotSources, ",") != strings.Join(wantSources, ",") {
t.Fatalf("source order = %v, want %v", gotSources, wantSources)
}
case <-time.After(time.Second):
t.Fatal("FetchBundle() did not finish after all source responses were released")
}
}
func TestFetchBundleReportsConcurrentFailuresInSourceOrder(t *testing.T) {
var requested []string
server := fixtureServer(t, map[string]handlerOverride{
"/forecast/hourly": {status: http.StatusBadRequest, body: `invalid hourly request`},
"/forecast/narrative": {status: http.StatusBadRequest, body: `invalid narrative request`},
}, &requested)
client := newTestClient(t, server.URL+"/", nil)
_, err := client.FetchBundle(context.Background())
if err == nil {
t.Fatal("FetchBundle() error = nil, want source error")
}
if !strings.Contains(err.Error(), "/forecast/hourly") {
t.Fatalf("error = %q, want the earlier hourly source failure", err.Error())
}
if !containsPath(requested, "/forecast/narrative") {
t.Fatalf("requested paths = %v, want independent narrative request", requested)
}
}
func TestFetchBundleCancelsConcurrentSourceRequests(t *testing.T) {
paths := []string{
"/observations",
"/forecast/hourly",
"/forecast/narrative",
"/alerts/active",
"/discussion",
"/weatherstories/latest",
convectiveOutlooksEndpoint,
}
started := make(chan string, len(paths))
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == currentConditionsEndpoint {
if !serveWeatherFixture(w, r) {
http.NotFound(w, r)
}
return
}
for _, path := range paths {
if r.URL.Path == path {
started <- path
<-r.Context().Done()
return
}
}
http.NotFound(w, r)
}))
defer server.Close()
client := newTestClient(t, server.URL+"/", nil)
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
result := make(chan error, 1)
go func() {
_, err := client.FetchBundle(ctx)
result <- err
}()
for range paths {
select {
case <-started:
case <-time.After(time.Second):
cancel()
t.Fatal("not all independent requests started before cancellation")
}
}
cancel()
select {
case err := <-result:
if err == nil || !strings.Contains(err.Error(), context.Canceled.Error()) {
t.Fatalf("FetchBundle() error = %v, want context cancellation", err)
}
case <-time.After(time.Second):
t.Fatal("FetchBundle() did not return after cancellation")
}
}
func TestFetchBundleRejectsInvalidHourlyPrecipitationProbability(t *testing.T) {
for _, probability := range []string{"-1", "101"} {
t.Run(probability, func(t *testing.T) {
@@ -369,8 +539,8 @@ func TestFetchRejectsOversizedResponseWithoutRetry(t *testing.T) {
if narrativeCalls != 1 {
t.Fatalf("narrative calls = %d, want no retry", narrativeCalls)
}
if containsPath(requested, "/alerts/active") {
t.Fatalf("requested paths = %v, want source failure before later fetches", requested)
if !containsPath(requested, "/alerts/active") {
t.Fatalf("requested paths = %v, want independent source requests despite narrative failure", requested)
}
}
@@ -912,21 +1082,34 @@ type handlerOverride struct {
handler http.HandlerFunc
}
var weatherFixtureFiles = map[string]string{
"/observations": "observations.json",
"/conditions/current": "current.json",
"/forecast/hourly": "hourly.json",
"/forecast/narrative": "narrative.json",
"/alerts/active": "alerts.json",
"/discussion": "discussion.json",
"/weatherstories/latest": "weather_story.json",
convectiveOutlooksEndpoint: "convective_outlooks.json",
}
func serveWeatherFixture(w http.ResponseWriter, r *http.Request) bool {
name, ok := weatherFixtureFiles[r.URL.Path]
if !ok {
return false
}
http.ServeFile(w, r, filepath.Join("testdata", name))
return true
}
func fixtureServer(t *testing.T, overrides map[string]handlerOverride, requested *[]string) *httptest.Server {
t.Helper()
fixtures := map[string]string{
"/observations": "observations.json",
"/conditions/current": "current.json",
"/forecast/hourly": "hourly.json",
"/forecast/narrative": "narrative.json",
"/alerts/active": "alerts.json",
"/discussion": "discussion.json",
"/weatherstories/latest": "weather_story.json",
convectiveOutlooksEndpoint: "convective_outlooks.json",
}
var requestedMu sync.Mutex
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if requested != nil {
requestedMu.Lock()
*requested = append(*requested, r.URL.String())
requestedMu.Unlock()
}
if override, ok := overrides[r.URL.Path]; ok {
if override.handler != nil {
@@ -937,12 +1120,9 @@ func fixtureServer(t *testing.T, overrides map[string]handlerOverride, requested
_, _ = w.Write([]byte(override.body))
return
}
name, ok := fixtures[r.URL.Path]
if !ok {
if !serveWeatherFixture(w, r) {
http.NotFound(w, r)
return
}
http.ServeFile(w, r, filepath.Join("testdata", name))
}))
t.Cleanup(server.Close)
return server