move providers into providers subdirectory

providers/bitcoin/README.md

@@ -0,0 +1,8 @@
+# Bitcoin Provider
+
+A provider for bitcoin, backed by blockstream.info to query address balance and coinconvert.net for fiat conversion.
+
+### Environment Variables
+
+* *bitcoin_address_[0...]* - A series of bitcoin addresses with a suffix of _0 and each additional address counting up.
+* *bitcoin_ynab_account* - The YNAB account ID used to keep track of Bitcoin balance

providers/bitcoin/address.go

@@ -0,0 +1,36 @@
+package bitcoin
+
+import (
+	"fmt"
+	"net/url"
+)
+
+type Address struct {
+	Address    string `json:"address"`
+	ChainStats struct {
+		FundedTxoCount int `json:"funded_txo_count"`
+		FundedTxoSum   int `json:"funded_txo_sum"`
+		SpentTxoCount  int `json:"spent_txo_count"`
+		SpentTxoSum    int `json:"spent_txo_sum"`
+		TxCount        int `json:"tx_count"`
+	} `json:"chain_stats"`
+	MempoolStats struct {
+		FundedTxoCount int `json:"funded_txo_count"`
+		FundedTxoSum   int `json:"funded_txo_sum"`
+		SpentTxoCount  int `json:"spent_txo_count"`
+		SpentTxoSum    int `json:"spent_txo_sum"`
+		TxCount        int `json:"tx_count"`
+	} `json:"mempool_stats"`
+}
+
+// GetAddress returns an Address struct populated with data from blockstream.info
+// for a given BTC address
+func (c *client) GetAddress(address string) (*Address, error) {
+	addressResponse := &Address{}
+
+	err := c.get(fmt.Sprintf("address/%s", address), addressResponse, url.Values{})
+	if err != nil {
+		return nil, err
+	}
+	return addressResponse, nil
+}

providers/bitcoin/client.go

@@ -0,0 +1,79 @@
+package bitcoin
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+const apiBaseURL = "https://blockstream.info/api/"
+
+// A client is the structure that will be used to consume the API
+// endpoints. It holds the login credentials, http client/transport,
+// rate limit information, and the login session timer.
+type client struct {
+	httpClient *http.Client
+	transport  *http.Transport
+}
+
+// Send an HTTP GET request, and return the processed response
+func (c *client) get(endpoint string, out interface{}, query url.Values) error {
+	req, err := http.NewRequest("GET", apiBaseURL+endpoint+"?"+query.Encode(), nil)
+	if err != nil {
+		return fmt.Errorf("failed to create new GET request: %v", err)
+	}
+
+	res, err := c.httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("http GET request failed: %v", err)
+	}
+
+	err = c.processResponse(res, out)
+	if err != nil {
+		return fmt.Errorf("failed to process response: %v", err)
+	}
+	return nil
+}
+
+// processResponse takes the body of an HTTP response, and either returns
+// the error code, or unmarshalls the JSON response, extracts
+// rate limit info, and places it into the object
+// output parameter. This function closes the response body after reading it.
+func (c *client) processResponse(res *http.Response, out interface{}) error {
+	body, err := io.ReadAll(res.Body)
+	res.Body.Close()
+	if err != nil {
+		return fmt.Errorf("failed to read response body: %v", err)
+	}
+
+	if res.StatusCode != 200 && res.StatusCode != 201 {
+		return fmt.Errorf("unexpected http status code '%d': %v", res.StatusCode, err)
+	}
+
+	err = json.Unmarshal(body, out)
+	if err != nil {
+		return fmt.Errorf("failed to unmarshal response body: %v", err)
+	}
+	return nil
+}
+
+// newClient is the factory function for clients
+func newClient() (*client, error) {
+	transport := &http.Transport{
+		ResponseHeaderTimeout: 5 * time.Second,
+	}
+
+	httpClient := &http.Client{
+		Transport: transport,
+	}
+
+	// Create a new client
+	c := &client{
+		httpClient: httpClient,
+		transport:  transport,
+	}
+	return c, nil
+}

providers/bitcoin/fiat.go

@@ -0,0 +1,41 @@
+package bitcoin
+
+import (
+	"fmt"
+	"net/http"
+)
+
+// example: https://api.coinconvert.net/convert/btc/cad?amount=1
+const fiatConvertURL = "https://api.coinconvert.net/convert/btc/cad"
+
+type FiatConversion struct {
+	Status string  `json:"status"`
+	BTC    int     `json:"BTC"`
+	CAD    float64 `json:"CAD"`
+}
+
+// BTC to CAD FIAT conversion - accepts an
+// amount in satoshi's and returns a CAD amount * 1000
+func (c *client) ConvertBTCToCAD(amount int) (int, error) {
+	fiatConversion := &FiatConversion{}
+
+	req, err := http.NewRequest("GET", fiatConvertURL+"?amount=1", nil)
+	if err != nil {
+		return 0, fmt.Errorf("failed to create new GET request: %v", err)
+	}
+
+	res, err := c.httpClient.Do(req)
+	if err != nil {
+		return 0, fmt.Errorf("http GET request failed: %v", err)
+	}
+
+	err = c.processResponse(res, fiatConversion)
+	if err != nil {
+		return 0, fmt.Errorf("failed to process response: %v", err)
+	}
+
+	if fiatConversion.Status != "success" {
+		return 0, fmt.Errorf("fiat conversion status was '%s' but expected 'success'", fiatConversion.Status)
+	}
+	return (amount * int(fiatConversion.CAD*1000)) / 100000000, nil // one BTC = one hundred million satoshi's
+}

providers/bitcoin/providerImpl.go

@@ -0,0 +1,70 @@
+package bitcoin
+
+import (
+	"fmt"
+	"os"
+)
+
+type Provider struct {
+	bitcoinAddresses []string // Slice of bitcoin addresses this provider monitors
+	ynabAccountID    string   // YNAB account ID this provider updates - all bitcoin addresses are summed up and mapped to this YNAB account
+	client           *client  // HTTP client for interacting with Questrade API
+}
+
+func (p *Provider) Name() string {
+	return "Bitcoin - Blockstream.info"
+}
+
+// Configures the provider for usage via environment variables and persistentData
+// If an error is returned, the provider will not be used
+func (p *Provider) Configure() error {
+	var err error
+
+	// Load environment variables in continous series with suffix starting at 0
+	// Multiple addresses can be configured, (eg _1, _2)
+	// As soon as the series is interrupted, we assume we're done
+	p.bitcoinAddresses = make([]string, 0)
+	for i := 0; true; i++ {
+		bitcoinAddress := os.Getenv(fmt.Sprintf("bitcoin_address_%d", i))
+		if bitcoinAddress == "" {
+			if i == 0 {
+				return fmt.Errorf("this account provider is not configured")
+			}
+			break
+		}
+		p.bitcoinAddresses = append(p.bitcoinAddresses, bitcoinAddress)
+	}
+	p.ynabAccountID = os.Getenv("bitcoin_ynab_account")
+
+	// Create new HTTP client
+	p.client, err = newClient()
+	if err != nil {
+		return fmt.Errorf("failed to create new bitcoin client: %v", err)
+	}
+	return nil
+}
+
+// Returns slices of account balances and mapped YNAB account IDs, along with an error
+func (p *Provider) GetBalances() ([]int, []string, error) {
+
+	balances := make([]int, 0)
+	ynabAccountIDs := make([]string, 0)
+	var satoshiBalance int
+	for _, bitcoinAddress := range p.bitcoinAddresses {
+		addressResponse, err := p.client.GetAddress(bitcoinAddress)
+		if err != nil {
+			return balances, ynabAccountIDs, fmt.Errorf("failed to get bitcoin address '%s': %v", bitcoinAddress, err)
+		}
+
+		satoshiBalance += addressResponse.ChainStats.FundedTxoSum - addressResponse.ChainStats.SpentTxoSum
+	}
+
+	fiatBalance, err := p.client.ConvertBTCToCAD(satoshiBalance)
+	if err != nil {
+		return balances, ynabAccountIDs, fmt.Errorf("failed to convert satoshi balance to fiat balance: %v", err)
+	}
+
+	balances = append(balances, fiatBalance)
+	ynabAccountIDs = append(ynabAccountIDs, p.ynabAccountID)
+	return balances, ynabAccountIDs, nil
+}