Simplify Go Endpoints + Add Tests (#120)

This MR represents a major refactor of the Go codebase, as well as introducing tests for the handlers. The MR also introduces an endpoint to shutdown or restart the Go server, which may be useful for clients who want to refresh the state of the plugin after checking out branches. Finally, this MR adds a contributing document for users who want to make feature changes.

cmd/resolve_discussion.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"fmt"
 	"io"
 	"net/http"
 
@@ -13,57 +14,61 @@ type DiscussionResolveRequest struct {
 	Resolved     bool   `json:"resolved"`
 }
 
-func DiscussionResolveHandler(w http.ResponseWriter, r *http.Request) {
-	switch r.Method {
-	case http.MethodPut:
-		DiscussionResolve(w, r)
-	default:
-		w.WriteHeader(http.StatusMethodNotAllowed)
-	}
-}
-func DiscussionResolve(w http.ResponseWriter, r *http.Request) {
+/* discussionsResolveHandler sets a discussion to be "resolved" or not resolved, depending on the payload */
+func (a *api) discussionsResolveHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json")
-	c := r.Context().Value("client").(Client)
+	if r.Method != http.MethodPut {
+		w.Header().Set("Access-Control-Allow-Methods", http.MethodPut)
+		handleError(w, InvalidRequestError{}, "Expected PUT", http.StatusMethodNotAllowed)
+		return
+	}
 
 	body, err := io.ReadAll(r.Body)
 	if err != nil {
-		c.handleError(w, err, "Could not read request body", http.StatusBadRequest)
-		return
-	}
-	defer r.Body.Close()
-	var resolveDiscussionRequest DiscussionResolveRequest
-	err = json.Unmarshal(body, &resolveDiscussionRequest)
-	if err != nil {
-		c.handleError(w, err, "Could not read JSON from request", http.StatusBadRequest)
+		handleError(w, err, "Could not read request body", http.StatusBadRequest)
 		return
 	}
 
-	_, res, err := c.git.Discussions.ResolveMergeRequestDiscussion(
-		c.projectId,
-		c.mergeId,
+	defer r.Body.Close()
+
+	var resolveDiscussionRequest DiscussionResolveRequest
+	err = json.Unmarshal(body, &resolveDiscussionRequest)
+
+	if err != nil {
+		handleError(w, err, "Could not read JSON from request", http.StatusBadRequest)
+		return
+	}
+
+	_, res, err := a.client.ResolveMergeRequestDiscussion(
+		a.projectInfo.ProjectId,
+		a.projectInfo.MergeId,
 		resolveDiscussionRequest.DiscussionID,
 		&gitlab.ResolveMergeRequestDiscussionOptions{Resolved: &resolveDiscussionRequest.Resolved},
 	)
 
+	friendlyName := "unresolve"
+	if resolveDiscussionRequest.Resolved {
+		friendlyName = "resolve"
+	}
+
 	if err != nil {
-		c.handleError(w, err, "Could not update resolve status of discussion", res.StatusCode)
+		handleError(w, err, fmt.Sprintf("Could not %s discussion", friendlyName), http.StatusInternalServerError)
+		return
+	}
+
+	if res.StatusCode >= 300 {
+		handleError(w, GenericError{endpoint: "/discussions/resolve"}, fmt.Sprintf("Could not %s discussion", friendlyName), res.StatusCode)
 		return
 	}
 
 	w.WriteHeader(http.StatusOK)
-	var message string
-	if resolveDiscussionRequest.Resolved {
-		message = "Discussion resolved"
-	} else {
-		message = "Discussion unresolved"
-	}
 	response := SuccessResponse{
-		Message: message,
+		Message: fmt.Sprintf("Discussion %sd", friendlyName),
 		Status:  http.StatusOK,
 	}
 
 	err = json.NewEncoder(w).Encode(response)
 	if err != nil {
-		c.handleError(w, err, "Could not encode response", http.StatusInternalServerError)
+		handleError(w, err, "Could not encode response", http.StatusInternalServerError)
 	}
 }