Add more debug logging to help debug issues in the future

config/dependency.go

@@ -276,6 +276,7 @@ func shouldReturnMockOutputs(dependencyConfig Dependency, terragruntOptions *opt
 // terragrunt config and extract the desired output from the remote state. Note that this will error if the targetted
 // module hasn't been applied yet.
 func getTerragruntOutput(dependencyConfig Dependency, terragruntOptions *options.TerragruntOptions) (*cty.Value, bool, error) {
+
 	// target config check: make sure the target config exists
 	targetConfig := getCleanedTargetConfigPath(dependencyConfig, terragruntOptions)
 	if !util.FileExists(targetConfig) {
@@ -309,6 +310,11 @@ func getOutputJsonWithCaching(targetConfig string, terragruntOptions *options.Te
 	defer actualLock.Unlock()
 	actualLock.Lock()
 
+	// This debug log is useful for validating if the locking mechanism is working. If the locking mechanism is working,
+	// we should only see one pair of logs at a time that begin with this statement, and then the relevant "terraform
+	// output" log for the dependency.
+	util.Debugf(terragruntOptions.Logger, "Getting output of dependency %s for config %s", targetConfig, terragruntOptions.TerragruntConfigPath)
+
 	// Look up if we have already run terragrunt output for this target config
 	rawJsonBytes, hasRun := jsonOutputCache.Load(targetConfig)
 	if hasRun {

main.go

@@ -17,6 +17,10 @@ var VERSION string
 
 // The main entrypoint for Terragrunt
 func main() {
+	// Log the terragrunt version in debug mode. This helps with debugging issues and ensuring a specific version of
+	// terragrunt used.
+	util.Debugf(util.CreateLogger(""), "Terragrunt Version: %s", VERSION)
+
 	defer errors.Recover(checkForErrorsAndExit)
 
 	app := cli.CreateTerragruntCli(VERSION, os.Stdout, os.Stderr)