chore: Move httpapi, httpmw, & database into coderd (#568)

* chore: Move httpmw to /coderd directory
httpmw is specific to coderd and should be scoped under coderd

* chore: Move httpapi to /coderd directory
httpapi is specific to coderd and should be scoped under coderd

* chore: Move database  to /coderd directory
database is specific to coderd and should be scoped under coderd

* chore: Update codecov & gitattributes for generated files
* chore: Update Makefile

coderd/httpmw/workspaceagent.go

@@ -0,0 +1,65 @@
+package httpmw
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/google/uuid"
+
+	"github.com/coder/coder/coderd/database"
+	"github.com/coder/coder/coderd/httpapi"
+)
+
+type workspaceAgentContextKey struct{}
+
+// WorkspaceAgent returns the workspace agent from the ExtractAgent handler.
+func WorkspaceAgent(r *http.Request) database.WorkspaceAgent {
+	user, ok := r.Context().Value(workspaceAgentContextKey{}).(database.WorkspaceAgent)
+	if !ok {
+		panic("developer error: agent middleware not provided")
+	}
+	return user
+}
+
+// ExtractWorkspaceAgent requires authentication using a valid agent token.
+func ExtractWorkspaceAgent(db database.Store) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+			cookie, err := r.Cookie(AuthCookie)
+			if err != nil {
+				httpapi.Write(rw, http.StatusUnauthorized, httpapi.Response{
+					Message: fmt.Sprintf("%q cookie must be provided", AuthCookie),
+				})
+				return
+			}
+			token, err := uuid.Parse(cookie.Value)
+			if err != nil {
+				httpapi.Write(rw, http.StatusBadRequest, httpapi.Response{
+					Message: fmt.Sprintf("parse token: %s", err),
+				})
+				return
+			}
+			agent, err := db.GetWorkspaceAgentByAuthToken(r.Context(), token)
+			if errors.Is(err, sql.ErrNoRows) {
+				if errors.Is(err, sql.ErrNoRows) {
+					httpapi.Write(rw, http.StatusUnauthorized, httpapi.Response{
+						Message: "agent token is invalid",
+					})
+					return
+				}
+			}
+			if err != nil {
+				httpapi.Write(rw, http.StatusInternalServerError, httpapi.Response{
+					Message: fmt.Sprintf("get workspace agent: %s", err),
+				})
+				return
+			}
+
+			ctx := context.WithValue(r.Context(), workspaceAgentContextKey{}, agent)
+			next.ServeHTTP(rw, r.WithContext(ctx))
+		})
+	}
+}