Improve error handling for ending tracing

Author: edoardopirovano

lib/tracer-config.js

@@ -26,21 +26,30 @@ export async function endTracingForCluster(
   // If there are no traced languages, we don't need to do anything.
   if (!config.languages.some(isTracedLanguage)) return;
 
-  const endTracingEnvVariables: Map<string, string | null> = JSON.parse(
-    fs.readFileSync(
-      path.resolve(
-        config.dbLocation,
-        "temp/tracingEnvironment/end-tracing.json"
-      ),
-      "utf8"
-    )
+  const envVariablesFile = path.resolve(
+    config.dbLocation,
+    "temp/tracingEnvironment/end-tracing.json"
   );
-  for (const [key, value] of Object.entries(endTracingEnvVariables)) {
-    if (value !== null) {
-      process.env[key] = value;
-    } else {
-      delete process.env[key];
+  if (!fs.existsSync(envVariablesFile)) {
+    throw new Error(
+      `Environment file for ending tracing not found: ${envVariablesFile}`
+    );
+  }
+  try {
+    const endTracingEnvVariables: Map<string, string | null> = JSON.parse(
+      fs.readFileSync(envVariablesFile, "utf8")
+    );
+    for (const [key, value] of Object.entries(endTracingEnvVariables)) {
+      if (value !== null) {
+        process.env[key] = value;
+      } else {
+        delete process.env[key];
+      }
     }
+  } catch (e) {
+    throw new Error(
+      `Failed to parse file containing end tracing environment variables: ${e}`
+    );
   }
 }