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KatharineKatharine
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Add (real, non-crypto) currency conversion.
Signed-off-by: Katharine Berry <[email protected]>
1 parent ec8443f commit a352878

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6 files changed

+500
-14
lines changed

6 files changed

+500
-14
lines changed

‎service/assistant/config/config.go‎

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Original file line numberDiff line numberDiff line change
@@ -22,6 +22,7 @@ type Config struct {
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GeminiKey string
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MapboxKey string
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IBMKey string
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ExchangeRateApiKey string
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RedisURL string
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UserIdentificationURL string
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HoneycombKey string
@@ -38,6 +39,7 @@ func init() {
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GeminiKey: os.Getenv("GEMINI_KEY"),
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MapboxKey: os.Getenv("MAPBOX_KEY"),
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IBMKey: os.Getenv("IBM_KEY"),
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ExchangeRateApiKey: os.Getenv("EXCHANGE_RATE_API_KEY"),
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RedisURL: os.Getenv("REDIS_URL"),
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UserIdentificationURL: os.Getenv("USER_IDENTIFICATION_URL"),
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HoneycombKey: os.Getenv("HONEYCOMB_KEY"),

‎service/assistant/functions/currency.go‎

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@@ -0,0 +1,111 @@
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// Copyright 2025 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package functions
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import (
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"context"
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"fmt"
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"log"
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"github.com/honeycombio/beeline-go"
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"google.golang.org/genai"
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"github.com/pebble-dev/bobby-assistant/service/assistant/quota"
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"github.com/pebble-dev/bobby-assistant/service/assistant/util/currencies"
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)
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type CurrencyConversionRequest struct {
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Amount float64
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From string
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To string
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}
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type CurrencyConversionResponse struct {
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Amount string // we return a nicely formatted string for the LLM's benefit
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Currency string
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}
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func init() {
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registerFunction(Registration{
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Definition: genai.FunctionDeclaration{
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Name: "convert_currency",
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Description: "Convert an amount of one (real, non-crypto) currency to another. *Always* call this function to get exchange rates when doing currency conversion - never use memorised rates.",
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Parameters: &genai.Schema{
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Type: genai.TypeObject,
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Nullable: false,
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Properties: map[string]*genai.Schema{
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"amount": {
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Type: genai.TypeNumber,
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Format: "double",
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Description: "The amount of currency to convert.",
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Nullable: false,
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},
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"from": {
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Type: genai.TypeString,
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Description: "The currency code to convert from.",
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Nullable: false,
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},
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"to": {
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Type: genai.TypeString,
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Description: "The currency code to convert to.",
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},
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},
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Required: []string{"amount", "from", "to"},
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},
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},
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Fn: convertCurrency,
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Thought: convertCurrencyThought,
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InputType: CurrencyConversionRequest{},
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})
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}
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func convertCurrency(ctx context.Context, qt *quota.Tracker, input interface{}) interface{} {
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ctx, span := beeline.StartSpan(ctx, "convert_currency")
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defer span.Send()
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ccr := input.(*CurrencyConversionRequest)
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if !currencies.IsValidCurrency(ccr.From) {
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return Error{Error: "Unknown currency code " + ccr.From}
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}
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if !currencies.IsValidCurrency(ccr.To) {
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return Error{Error: "Unknown currency code " + ccr.To}
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}
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cdm := currencies.GetCurrencyDataManager()
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data, err := cdm.GetExchangeData(ctx, ccr.From)
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if err != nil {
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log.Printf("error getting currency data for %s/%s: %v", ccr.From, ccr.To, err)
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return Error{Error: err.Error()}
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}
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if data == nil {
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return Error{Error: "returned currency data is nil!?"}
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}
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rate, ok := data.ConversionRates[ccr.To]
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if !ok {
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return Error{Error: fmt.Sprintf("No currency conversion available from %s to %s", ccr.From, ccr.To)}
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}
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result := rate * ccr.Amount
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return &CurrencyConversionResponse{
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Amount: fmt.Sprintf("%.2f", result),
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Currency: ccr.To,
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}
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}
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func convertCurrencyThought(input interface{}) string {
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return "Checking rates..."
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}

‎service/assistant/util/currencies/currencies.go‎

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@@ -0,0 +1,153 @@
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// Copyright 2025 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
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package currencies
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import (
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"context"
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"encoding/json"
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"errors"
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"fmt"
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"net/http"
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"net/url"
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"sync"
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"time"
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"github.com/honeycombio/beeline-go"
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"github.com/redis/go-redis/v9"
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"github.com/pebble-dev/bobby-assistant/service/assistant/config"
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"github.com/pebble-dev/bobby-assistant/service/assistant/util/storage"
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)
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type CurrencyExchangeData struct {
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Result string `json:"result"`
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ErrorType string `json:"error-type,omitempty"`
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TimeLastUpdateUnix int `json:"time_last_update_unix"`
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TimeNextUpdateUnix int `json:"time_next_update_unix"`
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BaseCode string `json:"base_code"`
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ConversionRates map[string]float64 `json:"conversion_rates"`
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}
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var sharedCurrencyDataManager *DataManager
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var sharedCurrencyDataManagerOnce sync.Once
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func GetCurrencyDataManager() *DataManager {
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sharedCurrencyDataManagerOnce.Do(func() {
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sharedCurrencyDataManager = &DataManager{
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redisClient: storage.GetRedis(),
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}
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})
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return sharedCurrencyDataManager
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}
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type DataManager struct {
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redisClient *redis.Client
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}
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var ErrUnknownCurrency = errors.New("unknown currency code")
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var ErrQuotaExceeded = errors.New("quota exceeded")
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func (dm *DataManager) GetExchangeData(ctx context.Context, from string) (*CurrencyExchangeData, error) {
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ctx, span := beeline.StartSpan(ctx, "get_exchange_data")
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defer span.Send()
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if !IsValidCurrency(from) {
66+
return nil, fmt.Errorf("unknown currency code %q", from)
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}
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data, err := dm.loadCachedData(ctx, from)
69+
if err != nil {
70+
return nil, fmt.Errorf("couldn't load cached data: %w", err)
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}
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if data != nil {
73+
return data, nil
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}
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// TODO: if we had high usage, we should prevent multiple concurrent requests for the same currency
76+
// but in practice this seems unlikely to be a major issue at our anticipated scale.
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data, err = dm.fetchExchangeRateData(ctx, from)
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if err != nil {
79+
return nil, fmt.Errorf("couldn't fetch exchange rate data: %w", err)
80+
}
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if err := dm.cacheData(ctx, from, data); err != nil {
82+
return nil, fmt.Errorf("error caching exchange rate data: %w", err)
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}
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return data, nil
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}
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func (dm *DataManager) fetchExchangeRateData(ctx context.Context, from string) (*CurrencyExchangeData, error) {
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ctx, span := beeline.StartSpan(ctx, "fetch_exchange_rate_data")
89+
defer span.Send()
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escaped := url.QueryEscape(from)
91+
request, err := http.NewRequest("GET", "https://v6.exchangerate-api.com/v6/"+config.GetConfig().ExchangeRateApiKey+"/latest/"+escaped, nil)
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if err != nil {
93+
return nil, err
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}
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resp, err := http.DefaultClient.Do(request)
96+
if err != nil {
97+
return nil, err
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}
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defer resp.Body.Close()
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var data CurrencyExchangeData
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if err := json.NewDecoder(resp.Body).Decode(&data); err != nil {
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return nil, err
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}
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if data.Result != "success" {
105+
if data.Result != "error" {
106+
return nil, fmt.Errorf("unexpected result %q", data.Result)
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}
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switch data.ErrorType {
109+
case "unsupported-code":
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return nil, ErrUnknownCurrency
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case "quota-reached":
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return nil, ErrQuotaExceeded
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default:
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return nil, fmt.Errorf("error fetching currency data: %s", data.ErrorType)
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}
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}
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return &data, nil
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}
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func (dm *DataManager) cacheData(ctx context.Context, currency string, data *CurrencyExchangeData) error {
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ctx, span := beeline.StartSpan(ctx, "cache_data")
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defer span.Send()
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encoded, err := json.Marshal(data)
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if err != nil {
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return err
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}
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expirationTime := time.Unix(int64(data.TimeNextUpdateUnix+5), 0)
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if err := dm.redisClient.Set(ctx, keyFromCurrency(currency), encoded, expirationTime.Sub(time.Now())).Err(); err != nil {
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return err
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}
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return nil
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}
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func (dm *DataManager) loadCachedData(ctx context.Context, currency string) (*CurrencyExchangeData, error) {
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ctx, span := beeline.StartSpan(ctx, "load_cached_data")
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defer span.Send()
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data, err := dm.redisClient.Get(ctx, keyFromCurrency(currency)).Result()
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if err != nil {
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if errors.Is(err, redis.Nil) {
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return nil, nil
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}
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return nil, err
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}
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var decoded CurrencyExchangeData
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if err := json.Unmarshal([]byte(data), &decoded); err != nil {
146+
return nil, err
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}
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return &decoded, nil
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}
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func keyFromCurrency(from string) string {
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return "currency:" + from
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}

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