set max limit on number of impacted project per action (#2049)

* set max limit on number of impacted project per action

Author: motatoes

backend/config/envgetters.go

@@ -1,6 +1,8 @@
 package config
 
 import (
+	"github.com/spf13/cast"
+	"log/slog"
 	"os"
 )
 
@@ -9,3 +11,17 @@ func LimitByNumOfFilesChanged() bool {
 	// number of files changed
 	return os.Getenv("DIGGER_LIMIT_MAX_PROJECTS_TO_FILES_CHANGED") == "1"
 }
+
+func MaxImpactedProjectsPerChange() int {
+	m := os.Getenv("DIGGER_MAX_PROJECTS_PER_CHANGE")
+	if m == "" {
+		return 99999
+	} else {
+		v, err := cast.ToIntE(m)
+		if err != nil {
+			slog.Warn("unable to cast DIGGER_MAX_PROJECTS_PER_CHANGE to int, defaulting to 99999", "DIGGER_MAX_PROJECTS_PER_CHANGE", m)
+			return 99999
+		}
+		return v
+	}
+}

backend/controllers/github.go

@@ -610,6 +610,26 @@ func handlePullRequestEvent(gh utils.GithubClientProvider, payload *github.PullR
 		}
 	}
 
+	maxImpactedProjectsPerChange := config2.MaxImpactedProjectsPerChange()
+	if len(impactedProjects) > maxImpactedProjectsPerChange {
+		slog.Error("Number of impacted projects exceeds number of changed files",
+			"prNumber", prNumber,
+			"impactedProjectCount", len(impactedProjects),
+			"changedFileCount", len(changedFiles),
+		)
+
+		commentReporterManager.UpdateComment(fmt.Sprintf(":x: Error the number impacted projects %v exceeds Max allowed ImpactedProjectsPerChange: %v, we set this limit to protect against hitting github API limits", len(impactedProjects), maxImpactedProjectsPerChange))
+
+		slog.Debug("Detailed event information",
+			slog.Group("details",
+				slog.Any("changedFiles", changedFiles),
+				slog.Int("configLength", len(diggerYmlStr)),
+				slog.Int("impactedProjectCount", len(impactedProjects)),
+			),
+		)
+		return fmt.Errorf("error processing event")
+	}
+
 	diggerCommand, err := orchestrator_scheduler.GetCommandFromJob(jobsForImpactedProjects[0])
 	if err != nil {
 		slog.Error("Could not determine Digger command from job",
@@ -1442,6 +1462,26 @@ func handleIssueCommentEvent(gh utils.GithubClientProvider, payload *github.Issu
 		}
 	}
 
+	maxImpactedProjectsPerChange := config2.MaxImpactedProjectsPerChange()
+	if len(impactedProjects) > maxImpactedProjectsPerChange {
+		slog.Error("Number of impacted projects exceeds number of changed files",
+			"prNumber", issueNumber,
+			"impactedProjectCount", len(impactedProjects),
+			"changedFileCount", len(changedFiles),
+		)
+
+		commentReporterManager.UpdateComment(fmt.Sprintf(":x: Error the number impacted projects %v exceeds Max allowed ImpactedProjectsPerChange: %v, we set this limit to protect against hitting github API limits", len(impactedProjects), maxImpactedProjectsPerChange))
+
+		slog.Debug("Detailed event information",
+			slog.Group("details",
+				slog.Any("changedFiles", changedFiles),
+				slog.Int("configLength", len(diggerYmlStr)),
+				slog.Int("impactedProjectCount", len(impactedProjects)),
+			),
+		)
+		return fmt.Errorf("error processing event")
+	}
+
 	// perform unlocking in backend
 	if config.PrLocks {
 		slog.Info("Processing PR locks for impacted projects",

fly-pro.toml

@@ -12,7 +12,7 @@ primary_region = 'lhr'
   JWT_AUTH = 'true'
   DIGGER_PROJECTS_SVC_APP_NAME = 'projects-refresh-service'
   DIGGER_LOAD_PROJECTS_ON_PUSH = 'true'
-
+  DIGGER_MAX_PROJECTS_PER_CHANGE=100
 
 [build]
   dockerfile = 'Dockerfile_backend_ee'