Handle non-200 responses from SonarQube API

Instead of letting the `json.Unmarshal` fail due to 401, return a
speaking error message.

SonarQube returns error messages for different failures. They are now
processed and printed into the bot log. They might help identify some
configuration errors.

Signed-off-by: Steven Kriegler <sk.bunsenbrenner@gmail.com>

internal/clients/sonarqube/measures.go

@@ -28,6 +28,7 @@ type MeasuresComponent struct {
 type MeasuresResponse struct {
 	Component MeasuresComponent         `json:"component"`
 	Metrics   []MeasuresComponentMetric `json:"metrics"`
+	Errors    []Error                   `json:"errors"`
 }
 
 func (mr *MeasuresResponse) GetRenderedMarkdownTable() string {

internal/clients/sonarqube/pulls.go

@@ -9,6 +9,7 @@ type PullRequest struct {
 
 type PullsResponse struct {
 	PullRequests []PullRequest `json:"pullRequests"`
+	Errors       []Error       `json:"errors"`
 }
 
 func (r *PullsResponse) GetPullRequest(name string) *PullRequest {

internal/clients/sonarqube/sonarqube.go

@@ -44,6 +44,11 @@ func retrieveDataFromApi[T PullsResponse | MeasuresResponse](sdk *SonarQubeSdk,
 	if err != nil {
 		return nil, err
 	}
+
+	if rawResponse.StatusCode == http.StatusUnauthorized {
+		return nil, fmt.Errorf("missing or invalid API token")
+	}
+
 	if rawResponse.Body != nil {
 		defer rawResponse.Body.Close()
 	}
@@ -60,6 +65,10 @@ func retrieveDataFromApi[T PullsResponse | MeasuresResponse](sdk *SonarQubeSdk,
 	return wrapper, nil
 }
 
+type Error struct {
+	Message string `json:"msg"`
+}
+
 type SonarQubeSdkInterface interface {
 	GetMeasures(string, string) (*MeasuresResponse, error)
 	GetPullRequestUrl(string, int64) string
@@ -91,7 +100,16 @@ func (sdk *SonarQubeSdk) fetchPullRequests(project string) (*PullsResponse, erro
 		return nil, err
 	}
 
-	return retrieveDataFromApi(sdk, request, &PullsResponse{})
+	response, err := retrieveDataFromApi(sdk, request, &PullsResponse{})
+	if err != nil {
+		return nil, err
+	}
+
+	if len(response.Errors) != 0 {
+		return nil, fmt.Errorf("%s", response.Errors[0].Message)
+	}
+
+	return response, nil
 }
 
 func (sdk *SonarQubeSdk) GetPullRequest(project string, index int64) (*PullRequest, error) {
@@ -116,7 +134,16 @@ func (sdk *SonarQubeSdk) GetMeasures(project string, branch string) (*MeasuresRe
 		return nil, err
 	}
 
-	return retrieveDataFromApi(sdk, request, &MeasuresResponse{})
+	response, err := retrieveDataFromApi(sdk, request, &MeasuresResponse{})
+	if err != nil {
+		return nil, err
+	}
+
+	if len(response.Errors) != 0 {
+		return nil, fmt.Errorf("%s", response.Errors[0].Message)
+	}
+
+	return response, nil
 }
 
 func (sdk *SonarQubeSdk) ComposeGiteaComment(data *CommentComposeData) (string, error) {