[CI] update-semconv-mounts.pl: warn if semconv submod not init (#8307)

Author: chalin

scripts/update-semconv-mounts.pl

@@ -1,10 +1,15 @@
 #!/usr/bin/perl -w
 #
-# Script to generate module.yaml from module-template.yaml
-# by adding autogenerated semconv mount entries.
+# Script to generate module.yaml from module-template.yaml by adding
+# autogenerated semconv mount entries. The entries are generated from the list
+# of README.md files in the semconv submodule.
 #
-# Reads from: $MODULE_CONFIG_TEMPLATE (version-controlled template)
-# Writes to:  $MODULE_CONFIG_YAML (generated, gitignored)
+# Note that this script might be called in situations where some but not all
+# content-modules have been initialized. If the semconv submodule is not
+# git-submodule initialized, the script will warn and exit.
+#
+# Reads from: $MODULE_CONFIG_TEMPLATE (version-controlled template) Writes to:
+# $MODULE_CONFIG_YAML (generated, gitignored)
 
 use strict;
 use warnings;
@@ -25,6 +30,27 @@ ($)
 my $END_MARKER = markerFor("above");
 
 sub main() {
+  if (! -e $SEMCONV_DIR) {
+    # The directory should be present even if the submodule isn't initialized.
+    print STDERR "ERROR: submodule directory not found: $SEMCONV_DIR\n";
+    exit 1;
+  }
+
+  if (! -e "$SEMCONV_DIR/.git") {
+    print STDERR
+      "WARNING: submodule not initialized, '.git' directory not found in $SEMCONV_DIR\n" .
+      "         Skipping semconv mount config generation.\n" .
+      "         Run 'npm run get:submodule' to initialize.\n";
+    exit 0;
+  } else {
+    print STDERR "Submodule found and initialized: $SEMCONV_DIR\n";
+  }
+
+  if (! -e $SEMCONV_DOCS_DIR) {
+    print STDERR "ERROR: directory '$SEMCONV_DOCS_DIR' expected but not found.\n";
+    exit 1;
+  }
+
   # Find all README.md by running system `find`. Must be in
   # $SEMCONV_DIR for find to generate the correct relative paths
   my $readme_files = `cd $SEMCONV_DIR && find docs -name "README.md" | sort`;