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Implement warmup and fetch retry in the weatherapi adapter

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This commit is contained in:
Eric Rakestraw
2026-07-02 11:33:16 -05:00
parent dc11e08e22
commit 27506168f8
4 changed files with 409 additions and 30 deletions
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205
internal/adapters/weatherapi/client.go
View File

@@ -24,6 +24,12 @@ import (
const (
convectiveOutlooksEndpoint = "/outlooks/convective"
sourceSPCConvectiveOutlooks = "spc_convective_outlooks"
defaultWarmupEndpoint = "/conditions/current"
defaultWarmupAttempts = 3
defaultWarmupDelay = time.Second
defaultFetchAttempts = 2
defaultFetchRetryDelay = time.Second
)
type Client struct {
@@ -35,6 +41,12 @@ type Client struct {
precision int
missingSource config.MissingSourceConfig
now func() time.Time
warmupEndpoint string
warmupAttempts int
warmupDelay time.Duration
fetchAttempts int
fetchRetryDelay time.Duration
}
type Option func(*Client)
@@ -80,7 +92,12 @@ func New(cfg config.Config, opts ...Option) (*Client, error) {
Default: cfg.MissingSource.Default,
Sources: cfg.MissingSource.Sources,
},
now: time.Now,
now: time.Now,
warmupEndpoint: defaultWarmupEndpoint,
warmupAttempts: defaultWarmupAttempts,
warmupDelay: defaultWarmupDelay,
fetchAttempts: defaultFetchAttempts,
fetchRetryDelay: defaultFetchRetryDelay,
}
for _, opt := range opts {
opt(client)
@@ -89,6 +106,10 @@ func New(cfg config.Config, opts ...Option) (*Client, error) {
}
func (c *Client) FetchBundle(ctx context.Context) (*weatherdata.Bundle, error) {
if err := c.warmup(ctx); err != nil {
return nil, err
}
fetchedAt := c.now()
builder := bundleBuilder{
client: c,
@@ -397,24 +418,9 @@ type envelope struct {
}
func (c *Client) fetch(ctx context.Context, sourceName string, endpoint string, opts queryOptions) (json.RawMessage, weatherdata.Source, error) {
reqURL := c.endpointURL(endpoint, opts)
req, err := http.NewRequestWithContext(ctx, http.MethodGet, reqURL.String(), nil)
reqURL, body, err := c.fetchHTTP(ctx, endpoint, opts)
if err != nil {
return nil, weatherdata.Source{}, fmt.Errorf("create request for %s: %w", endpoint, err)
}
resp, err := c.httpClient.Do(req)
if err != nil {
return nil, weatherdata.Source{}, fmt.Errorf("fetch %s: %w", endpoint, err)
}
defer resp.Body.Close()
body, err := io.ReadAll(io.LimitReader(resp.Body, 10<<20))
if err != nil {
return nil, weatherdata.Source{}, fmt.Errorf("read %s response: %w", endpoint, err)
}
if resp.StatusCode < 200 || resp.StatusCode >= 300 {
return nil, weatherdata.Source{}, fmt.Errorf("fetch %s: unexpected HTTP status %d: %s", endpoint, resp.StatusCode, strings.TrimSpace(string(body)))
return nil, weatherdata.Source{}, err
}
var env envelope
@@ -440,6 +446,169 @@ func (c *Client) fetch(ctx context.Context, sourceName string, endpoint string,
return env.Data, source, nil
}
func (c *Client) warmup(ctx context.Context) error {
endpoint := c.warmupEndpoint
if strings.TrimSpace(endpoint) == "" {
endpoint = defaultWarmupEndpoint
}
attempts := positiveAttemptCount(c.warmupAttempts)
var lastErr error
for attempt := 1; attempt <= attempts; attempt++ {
if err := ctx.Err(); err != nil {
return fmt.Errorf("warm up weather API via %s: %w", endpoint, err)
}
if err := c.warmupOnce(ctx, endpoint); err != nil {
lastErr = err
} else {
return nil
}
if attempt == attempts {
break
}
if err := waitForRetry(ctx, c.warmupDelay); err != nil {
return fmt.Errorf("warm up weather API via %s after %d attempt(s): %w", endpoint, attempt, err)
}
}
return fmt.Errorf("warm up weather API via %s failed after %d attempts: %w", endpoint, attempts, lastErr)
}
func (c *Client) warmupOnce(ctx context.Context, endpoint string) error {
reqURL := c.endpointURL(endpoint, queryOptions{precision: true})
req, err := http.NewRequestWithContext(ctx, http.MethodGet, reqURL.String(), nil)
if err != nil {
return fmt.Errorf("create request for %s: %w", endpoint, err)
}
resp, err := c.httpClient.Do(req)
if err != nil {
return fmt.Errorf("fetch %s: %w", endpoint, err)
}
defer resp.Body.Close()
body, err := io.ReadAll(io.LimitReader(resp.Body, 10<<20))
if err != nil {
return fmt.Errorf("read %s response: %w", endpoint, err)
}
if resp.StatusCode < 200 || resp.StatusCode >= 300 {
return fmt.Errorf("fetch %s: unexpected HTTP status %d: %s", endpoint, resp.StatusCode, strings.TrimSpace(string(body)))
}
return nil
}
func (c *Client) fetchHTTP(ctx context.Context, endpoint string, opts queryOptions) (*url.URL, []byte, error) {
attempts := positiveAttemptCount(c.fetchAttempts)
var lastErr error
var lastRetryable bool
for attempt := 1; attempt <= attempts; attempt++ {
if err := ctx.Err(); err != nil {
return nil, nil, fmt.Errorf("fetch %s: %w", endpoint, err)
}
reqURL, body, err := c.fetchHTTPOnce(ctx, endpoint, opts)
if err == nil {
return reqURL, body, nil
}
lastErr = err
lastRetryable = isRetryableRequestError(err)
if !lastRetryable || attempt == attempts {
break
}
if err := waitForRetry(ctx, c.fetchRetryDelay); err != nil {
return nil, nil, fmt.Errorf("fetch %s retry delay after attempt %d: %w", endpoint, attempt, err)
}
}
if lastRetryable {
return nil, nil, fmt.Errorf("fetch %s failed after %d attempts: %w", endpoint, attempts, lastErr)
}
return nil, nil, lastErr
}
func (c *Client) fetchHTTPOnce(ctx context.Context, endpoint string, opts queryOptions) (*url.URL, []byte, error) {
reqURL := c.endpointURL(endpoint, opts)
req, err := http.NewRequestWithContext(ctx, http.MethodGet, reqURL.String(), nil)
if err != nil {
return nil, nil, fmt.Errorf("create request for %s: %w", endpoint, err)
}
resp, err := c.httpClient.Do(req)
if err != nil {
err = fmt.Errorf("fetch %s: %w", endpoint, err)
if ctx.Err() != nil {
return reqURL, nil, err
}
return reqURL, nil, retryableRequestError{err: err}
}
defer resp.Body.Close()
body, err := io.ReadAll(io.LimitReader(resp.Body, 10<<20))
if err != nil {
err = fmt.Errorf("read %s response: %w", endpoint, err)
if ctx.Err() != nil {
return reqURL, nil, err
}
return reqURL, nil, retryableRequestError{err: err}
}
if resp.StatusCode < 200 || resp.StatusCode >= 300 {
err := fmt.Errorf("fetch %s: unexpected HTTP status %d: %s", endpoint, resp.StatusCode, strings.TrimSpace(string(body)))
if isRetryableHTTPStatus(resp.StatusCode) {
return reqURL, nil, retryableRequestError{err: err}
}
return reqURL, nil, err
}
return reqURL, body, nil
}
type retryableRequestError struct {
err error
}
func (e retryableRequestError) Error() string {
return e.err.Error()
}
func (e retryableRequestError) Unwrap() error {
return e.err
}
func isRetryableRequestError(err error) bool {
_, ok := err.(retryableRequestError)
return ok
}
func isRetryableHTTPStatus(status int) bool {
switch status {
case http.StatusRequestTimeout,
http.StatusTooManyRequests,
http.StatusInternalServerError,
http.StatusBadGateway,
http.StatusServiceUnavailable,
http.StatusGatewayTimeout:
return true
default:
return false
}
}
func waitForRetry(ctx context.Context, delay time.Duration) error {
if delay <= 0 {
return ctx.Err()
}
timer := time.NewTimer(delay)
defer timer.Stop()
select {
case <-ctx.Done():
return ctx.Err()
case <-timer.C:
return nil
}
}
func positiveAttemptCount(attempts int) int {
if attempts < 1 {
return 1
}
return attempts
}
func isJSONNull(raw json.RawMessage) bool {
return bytes.Equal(bytes.TrimSpace(raw), []byte("null"))
}

203
internal/adapters/weatherapi/client_test.go
View File

@@ -80,8 +80,11 @@ func TestFetchBundleFromFixtures(t *testing.T) {
"/weatherstories/latest",
convectiveOutlooksEndpoint,
}
if len(requested) != len(wantPaths) {
t.Fatalf("requested paths = %v, want %d source endpoints", requested, len(wantPaths))
if len(requested) != len(wantPaths)+1 {
t.Fatalf("requested paths = %v, want warmup plus %d source endpoints", requested, len(wantPaths))
}
if !strings.HasPrefix(requested[0], defaultWarmupEndpoint+"?") && requested[0] != defaultWarmupEndpoint {
t.Fatalf("first requested path = %q, want warmup endpoint %s", requested[0], defaultWarmupEndpoint)
}
for _, want := range wantPaths {
if !containsPath(requested, want) {
@@ -186,7 +189,7 @@ func TestFetchBundleRecordsSourceHash(t *testing.T) {
func TestHTTPErrorIsActionable(t *testing.T) {
server := fixtureServer(t, map[string]handlerOverride{
"/conditions/current": {status: http.StatusBadGateway, body: `upstream failed`},
"/forecast/hourly": {status: http.StatusBadGateway, body: `upstream failed`},
}, nil)
client := newTestClient(t, server.URL+"/", nil)
@@ -194,15 +197,140 @@ func TestHTTPErrorIsActionable(t *testing.T) {
if err == nil {
t.Fatal("FetchBundle() error = nil, want HTTP error")
}
if !strings.Contains(err.Error(), "/conditions/current") || !strings.Contains(err.Error(), "502") {
if !strings.Contains(err.Error(), "/forecast/hourly") || !strings.Contains(err.Error(), "502") {
t.Fatalf("error = %q, want endpoint and status", err.Error())
}
}
func TestWarmupRetriesBeforeFetchBundle(t *testing.T) {
var requested []string
var warmupCalls int
server := fixtureServer(t, map[string]handlerOverride{
defaultWarmupEndpoint: {handler: func(w http.ResponseWriter, r *http.Request) {
warmupCalls++
if warmupCalls == 1 {
w.WriteHeader(http.StatusBadGateway)
_, _ = w.Write([]byte("vpn waking up"))
return
}
http.ServeFile(w, r, filepath.Join("testdata", "current.json"))
}},
}, &requested)
client := newTestClient(t, server.URL+"/", nil)
bundle, err := client.FetchBundle(context.Background())
if err != nil {
t.Fatalf("FetchBundle() error = %v", err)
}
if bundle.Current == nil {
t.Fatal("Current = nil, want successful fetch after warmup retry")
}
if warmupCalls != 3 {
t.Fatalf("conditions/current calls = %d, want failed warmup, successful warmup, and current source fetch", warmupCalls)
}
if len(requested) < 2 || !containsPath(requested[:2], defaultWarmupEndpoint) {
t.Fatalf("initial requests = %v, want warmup endpoint retries", requested)
}
}
func TestWarmupFailureStopsBeforeSourceFetches(t *testing.T) {
var requested []string
server := fixtureServer(t, map[string]handlerOverride{
defaultWarmupEndpoint: {status: http.StatusBadGateway, body: `vpn unavailable`},
}, &requested)
client := newTestClient(t, server.URL+"/", nil)
client.warmupAttempts = 2
_, err := client.FetchBundle(context.Background())
if err == nil {
t.Fatal("FetchBundle() error = nil, want warmup failure")
}
if !strings.Contains(err.Error(), "warm up weather API") ||
!strings.Contains(err.Error(), defaultWarmupEndpoint) ||
!strings.Contains(err.Error(), "2 attempts") ||
!strings.Contains(err.Error(), "502") {
t.Fatalf("error = %q, want warmup endpoint, attempts, and status", err.Error())
}
if got := countPath(requested, defaultWarmupEndpoint); got != 2 {
t.Fatalf("warmup requests = %d, want 2; all requests = %v", got, requested)
}
if containsPath(requested, "/observations") {
t.Fatalf("requested paths = %v, want warmup failure before source fetches", requested)
}
}
func TestFetchRetriesRetryableStatus(t *testing.T) {
var hourlyCalls int
server := fixtureServer(t, map[string]handlerOverride{
"/forecast/hourly": {handler: func(w http.ResponseWriter, r *http.Request) {
hourlyCalls++
if hourlyCalls == 1 {
w.WriteHeader(http.StatusBadGateway)
_, _ = w.Write([]byte("temporary upstream failure"))
return
}
http.ServeFile(w, r, filepath.Join("testdata", "hourly.json"))
}},
}, nil)
client := newTestClient(t, server.URL+"/", nil)
bundle, err := client.FetchBundle(context.Background())
if err != nil {
t.Fatalf("FetchBundle() error = %v", err)
}
if bundle.Hourly == nil {
t.Fatal("Hourly = nil, want successful fetch after retry")
}
if hourlyCalls != 2 {
t.Fatalf("hourly calls = %d, want 2", hourlyCalls)
}
}
func TestFetchDoesNotRetryNonRetryableStatus(t *testing.T) {
var hourlyCalls int
server := fixtureServer(t, map[string]handlerOverride{
"/forecast/hourly": {handler: func(w http.ResponseWriter, r *http.Request) {
hourlyCalls++
w.WriteHeader(http.StatusNotFound)
_, _ = w.Write([]byte("not found"))
}},
}, nil)
client := newTestClient(t, server.URL+"/", nil)
_, err := client.FetchBundle(context.Background())
if err == nil {
t.Fatal("FetchBundle() error = nil, want non-retryable status error")
}
if hourlyCalls != 1 {
t.Fatalf("hourly calls = %d, want no retry", hourlyCalls)
}
}
func TestFetchDoesNotRetryMalformedEnvelope(t *testing.T) {
var hourlyCalls int
server := fixtureServer(t, map[string]handlerOverride{
"/forecast/hourly": {handler: func(w http.ResponseWriter, r *http.Request) {
hourlyCalls++
w.WriteHeader(http.StatusOK)
_, _ = w.Write([]byte(`not-json`))
}},
}, nil)
client := newTestClient(t, server.URL+"/", nil)
_, err := client.FetchBundle(context.Background())
if err == nil {
t.Fatal("FetchBundle() error = nil, want envelope decode error")
}
if hourlyCalls != 1 {
t.Fatalf("hourly calls = %d, want no retry", hourlyCalls)
}
}
func TestRequiredHourlyForecast(t *testing.T) {
var requested []string
server := fixtureServer(t, map[string]handlerOverride{
"/forecast/hourly": {status: http.StatusOK, body: `{"data": null}`},
}, nil)
}, &requested)
client := newTestClient(t, server.URL+"/", nil)
_, err := client.FetchBundle(context.Background())
@@ -212,6 +340,9 @@ func TestRequiredHourlyForecast(t *testing.T) {
if !strings.Contains(err.Error(), "hourly forecast data") {
t.Fatalf("error = %q, want hourly context", err.Error())
}
if got := countPath(requested, "/forecast/hourly"); got != 1 {
t.Fatalf("hourly requests = %d, want no retry; all requests = %v", got, requested)
}
}
func TestNullAlertsMeansNoActiveAlerts(t *testing.T) {
@@ -420,6 +551,43 @@ func TestContextCancellation(t *testing.T) {
}
}
func TestRetryDelayRespectsContextCancellation(t *testing.T) {
var cancel context.CancelFunc
var hourlyCalls int
server := fixtureServer(t, map[string]handlerOverride{
"/forecast/hourly": {handler: func(w http.ResponseWriter, r *http.Request) {
hourlyCalls++
if cancel != nil {
cancel()
}
w.WriteHeader(http.StatusBadGateway)
_, _ = w.Write([]byte("temporary upstream failure"))
}},
}, nil)
client := newTestClient(t, server.URL+"/", nil)
client.fetchRetryDelay = time.Hour
ctx, cancelFunc := context.WithCancel(context.Background())
cancel = cancelFunc
defer cancelFunc()
start := time.Now()
_, err := client.FetchBundle(ctx)
elapsed := time.Since(start)
if err == nil {
t.Fatal("FetchBundle() error = nil, want cancellation during retry delay")
}
if !strings.Contains(err.Error(), context.Canceled.Error()) {
t.Fatalf("error = %q, want context cancellation", err.Error())
}
if elapsed > time.Second {
t.Fatalf("FetchBundle() elapsed = %s, want prompt cancellation", elapsed)
}
if hourlyCalls != 1 {
t.Fatalf("hourly calls = %d, want retry delay cancellation before second attempt", hourlyCalls)
}
}
func TestHTTPTimeout(t *testing.T) {
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
time.Sleep(50 * time.Millisecond)
@@ -432,12 +600,14 @@ func TestHTTPTimeout(t *testing.T) {
if err != nil {
t.Fatalf("New() error = %v", err)
}
client.warmupDelay = 0
client.fetchRetryDelay = 0
_, err = client.FetchBundle(context.Background())
if err == nil {
t.Fatal("FetchBundle() error = nil, want timeout error")
}
if !strings.Contains(err.Error(), "/observations") {
if !strings.Contains(err.Error(), defaultWarmupEndpoint) {
t.Fatalf("error = %q, want endpoint context", err.Error())
}
}
@@ -464,8 +634,9 @@ func TestSaveBundle(t *testing.T) {
}
type handlerOverride struct {
status int
body string
status int
body string
handler http.HandlerFunc
}
func fixtureServer(t *testing.T, overrides map[string]handlerOverride, requested *[]string) *httptest.Server {
@@ -485,6 +656,10 @@ func fixtureServer(t *testing.T, overrides map[string]handlerOverride, requested
*requested = append(*requested, r.URL.String())
}
if override, ok := overrides[r.URL.Path]; ok {
if override.handler != nil {
override.handler(w, r)
return
}
w.WriteHeader(override.status)
_, _ = w.Write([]byte(override.body))
return
@@ -510,6 +685,8 @@ func newTestClient(t *testing.T, baseURL string, sourcePolicies map[string]confi
if err != nil {
t.Fatalf("New() error = %v", err)
}
client.warmupDelay = 0
client.fetchRetryDelay = 0
return client
}
@@ -532,6 +709,16 @@ func containsPath(requested []string, path string) bool {
return false
}
func countPath(requested []string, path string) int {
var count int
for _, rawURL := range requested {
if strings.HasPrefix(rawURL, path+"?") || rawURL == path {
count++
}
}
return count
}
func sourceByName(t *testing.T, sources []weatherdata.Source, name string) weatherdata.Source {
t.Helper()
for _, source := range sources {