1 files changed, 309 insertions, 0 deletions
diff --git a/cli/internal/client/client.go b/cli/internal/client/client.go
new file mode 100644
index 0000000..822b2df
--- /dev/null
+++ b/cli/internal/client/client.go
@@ -0,0 +1,309 @@
+// Package client implements some interfaces and convenience methods to interact with Vercel APIs and Remote Cache
+package client
+
+import (
+	"context"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"runtime"
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/go-retryablehttp"
+	"github.com/vercel/turbo/cli/internal/ci"
+)
+
+// APIClient is the main interface for making network requests to Vercel
+type APIClient struct {
+	// The api's base URL
+	baseURL      string
+	token        string
+	turboVersion string
+
+	// Must be used via atomic package
+	currentFailCount uint64
+	HTTPClient       *retryablehttp.Client
+	teamID           string
+	teamSlug         string
+	// Whether or not to send preflight requests before uploads
+	usePreflight bool
+}
+
+// ErrTooManyFailures is returned from remote cache API methods after `maxRemoteFailCount` errors have occurred
+var ErrTooManyFailures = errors.New("skipping HTTP Request, too many failures have occurred")
+
+// _maxRemoteFailCount is the number of failed requests before we stop trying to upload/download
+// artifacts to the remote cache
+const _maxRemoteFailCount = uint64(3)
+
+// SetToken updates the APIClient's Token
+func (c *APIClient) SetToken(token string) {
+	c.token = token
+}
+
+// RemoteConfig holds the authentication and endpoint details for the API client
+type RemoteConfig struct {
+	Token    string
+	TeamID   string
+	TeamSlug string
+	APIURL   string
+}
+
+// Opts holds values for configuring the behavior of the API client
+type Opts struct {
+	UsePreflight bool
+	Timeout      uint64
+}
+
+// ClientTimeout Exported ClientTimeout used in run.go
+const ClientTimeout uint64 = 20
+
+// NewClient creates a new APIClient
+func NewClient(remoteConfig RemoteConfig, logger hclog.Logger, turboVersion string, opts Opts) *APIClient {
+	client := &APIClient{
+		baseURL:      remoteConfig.APIURL,
+		turboVersion: turboVersion,
+		HTTPClient: &retryablehttp.Client{
+			HTTPClient: &http.Client{
+				Timeout: time.Duration(opts.Timeout) * time.Second,
+			},
+			RetryWaitMin: 2 * time.Second,
+			RetryWaitMax: 10 * time.Second,
+			RetryMax:     2,
+			Backoff:      retryablehttp.DefaultBackoff,
+			Logger:       logger,
+		},
+		token:        remoteConfig.Token,
+		teamID:       remoteConfig.TeamID,
+		teamSlug:     remoteConfig.TeamSlug,
+		usePreflight: opts.UsePreflight,
+	}
+	client.HTTPClient.CheckRetry = client.checkRetry
+	return client
+}
+
+// hasUser returns true if we have credentials for a user
+func (c *APIClient) hasUser() bool {
+	return c.token != ""
+}
+
+// IsLinked returns true if we have a user and linked team
+func (c *APIClient) IsLinked() bool {
+	return c.hasUser() && (c.teamID != "" || c.teamSlug != "")
+}
+
+// GetTeamID returns the currently configured team id
+func (c *APIClient) GetTeamID() string {
+	return c.teamID
+}
+
+func (c *APIClient) retryCachePolicy(resp *http.Response, err error) (bool, error) {
+	if err != nil {
+		if errors.As(err, &x509.UnknownAuthorityError{}) {
+			// Don't retry if the error was due to TLS cert verification failure.
+			atomic.AddUint64(&c.currentFailCount, 1)
+			return false, err
+		}
+		atomic.AddUint64(&c.currentFailCount, 1)
+		return true, nil
+	}
+
+	// 429 Too Many Requests is recoverable. Sometimes the server puts
+	// a Retry-After response header to indicate when the server is
+	// available to start processing request from client.
+	if resp.StatusCode == http.StatusTooManyRequests {
+		atomic.AddUint64(&c.currentFailCount, 1)
+		return true, nil
+	}
+
+	// Check the response code. We retry on 500-range responses to allow
+	// the server time to recover, as 500's are typically not permanent
+	// errors and may relate to outages on the server side. This will catch
+	// invalid response codes as well, like 0 and 999.
+	if resp.StatusCode == 0 || (resp.StatusCode >= 500 && resp.StatusCode != 501) {
+		atomic.AddUint64(&c.currentFailCount, 1)
+		return true, fmt.Errorf("unexpected HTTP status %s", resp.Status)
+	}
+
+	// swallow the error and stop retrying
+	return false, nil
+}
+
+func (c *APIClient) checkRetry(ctx context.Context, resp *http.Response, err error) (bool, error) {
+	// do not retry on context.Canceled or context.DeadlineExceeded
+	if ctx.Err() != nil {
+		atomic.AddUint64(&c.currentFailCount, 1)
+		return false, ctx.Err()
+	}
+
+	// we're squashing the error from the request and substituting any error that might come
+	// from our retry policy.
+	shouldRetry, err := c.retryCachePolicy(resp, err)
+	if shouldRetry {
+		// Our policy says it's ok to retry, but we need to check the failure count
+		if retryErr := c.okToRequest(); retryErr != nil {
+			return false, retryErr
+		}
+	}
+	return shouldRetry, err
+}
+
+// okToRequest returns nil if it's ok to make a request, and returns the error to
+// return to the caller if a request is not allowed
+func (c *APIClient) okToRequest() error {
+	if atomic.LoadUint64(&c.currentFailCount) < _maxRemoteFailCount {
+		return nil
+	}
+	return ErrTooManyFailures
+}
+
+func (c *APIClient) makeURL(endpoint string) string {
+	return fmt.Sprintf("%v%v", c.baseURL, endpoint)
+}
+
+func (c *APIClient) userAgent() string {
+	return fmt.Sprintf("turbo %v %v %v (%v)", c.turboVersion, runtime.Version(), runtime.GOOS, runtime.GOARCH)
+}
+
+// doPreflight returns response with closed body, latest request url, and any errors to the caller
+func (c *APIClient) doPreflight(requestURL string, requestMethod string, requestHeaders string) (*http.Response, string, error) {
+	req, err := retryablehttp.NewRequest(http.MethodOptions, requestURL, nil)
+	req.Header.Set("User-Agent", c.userAgent())
+	req.Header.Set("Access-Control-Request-Method", requestMethod)
+	req.Header.Set("Access-Control-Request-Headers", requestHeaders)
+	req.Header.Set("Authorization", "Bearer "+c.token)
+	if err != nil {
+		return nil, requestURL, fmt.Errorf("[WARNING] Invalid cache URL: %w", err)
+	}
+
+	// If resp is not nil, ignore any errors
+	//  because most likely unimportant for preflight to handle.
+	// Let follow-up request handle potential errors.
+	resp, err := c.HTTPClient.Do(req)
+	if resp == nil {
+		return resp, requestURL, err
+	}
+	defer resp.Body.Close() //nolint:golint,errcheck // nothing to do
+	// The client will continue following 307, 308 redirects until it hits
+	//  max redirects, gets an error, or gets a normal response.
+	// Get the url from the Location header or get the url used in the last
+	//  request (could have changed after following redirects).
+	// Note that net/http client does not continue redirecting the preflight
+	//  request with the OPTIONS method for 301, 302, and 303 redirects.
+	//  See golang/go Issue 18570.
+	if locationURL, err := resp.Location(); err == nil {
+		requestURL = locationURL.String()
+	} else {
+		requestURL = resp.Request.URL.String()
+	}
+	return resp, requestURL, nil
+}
+
+func (c *APIClient) addTeamParam(params *url.Values) {
+	if c.teamID != "" && strings.HasPrefix(c.teamID, "team_") {
+		params.Add("teamId", c.teamID)
+	}
+	if c.teamSlug != "" {
+		params.Add("slug", c.teamSlug)
+	}
+}
+
+// JSONPatch sends a byte array (json.marshalled payload) to a given endpoint with PATCH
+func (c *APIClient) JSONPatch(endpoint string, body []byte) ([]byte, error) {
+	resp, err := c.request(endpoint, http.MethodPatch, body)
+	if err != nil {
+		return nil, err
+	}
+
+	rawResponse, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response %v", err)
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("%s", string(rawResponse))
+	}
+
+	return rawResponse, nil
+}
+
+// JSONPost sends a byte array (json.marshalled payload) to a given endpoint with POST
+func (c *APIClient) JSONPost(endpoint string, body []byte) ([]byte, error) {
+	resp, err := c.request(endpoint, http.MethodPost, body)
+	if err != nil {
+		return nil, err
+	}
+
+	rawResponse, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response %v", err)
+	}
+
+	// For non 200/201 status codes, return the response body as an error
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
+		return nil, fmt.Errorf("%s", string(rawResponse))
+	}
+
+	return rawResponse, nil
+}
+
+func (c *APIClient) request(endpoint string, method string, body []byte) (*http.Response, error) {
+	if err := c.okToRequest(); err != nil {
+		return nil, err
+	}
+
+	params := url.Values{}
+	c.addTeamParam(&params)
+	encoded := params.Encode()
+	if encoded != "" {
+		encoded = "?" + encoded
+	}
+
+	requestURL := c.makeURL(endpoint + encoded)
+
+	allowAuth := true
+	if c.usePreflight {
+		resp, latestRequestURL, err := c.doPreflight(requestURL, method, "Authorization, User-Agent")
+		if err != nil {
+			return nil, fmt.Errorf("pre-flight request failed before trying to fetch files in HTTP cache: %w", err)
+		}
+
+		requestURL = latestRequestURL
+		headers := resp.Header.Get("Access-Control-Allow-Headers")
+		allowAuth = strings.Contains(strings.ToLower(headers), strings.ToLower("Authorization"))
+	}
+
+	req, err := retryablehttp.NewRequest(method, requestURL, body)
+	if err != nil {
+		return nil, err
+	}
+
+	// Set headers
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("User-Agent", c.userAgent())
+
+	if allowAuth {
+		req.Header.Set("Authorization", "Bearer "+c.token)
+	}
+
+	if ci.IsCi() {
+		req.Header.Set("x-artifact-client-ci", ci.Constant())
+	}
+
+	resp, err := c.HTTPClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	// If there isn't a response, something else probably went wrong
+	if resp == nil {
+		return nil, fmt.Errorf("response from %s is nil, something went wrong", requestURL)
+	}
+
+	return resp, nil
+}