Allow for printing the errors when you need to fix the parsing.

02-filter-a-log-file/chains_parser.js

@@ -139,7 +139,7 @@ class Parser {
   }
 }
 
-const parse_logs = async (file_name) => {
+const parse_logs = async (file_name, errors) => {
   const read_stream = fs.createReadStream(file_name);
 
   const rl = readline.createInterface({
@@ -179,6 +179,8 @@ const parse_logs = async (file_name) => {
 
       by_ip[data.ip] = ip_chain;
     } catch(error) {
+      if(errors) console.error(error);
+
       stats.errors += 1;
     }
   }
@@ -242,6 +244,7 @@ const output_results = (min, chains_sorted) => {
 program
   .option("--no-set", "Use a Set instead of a list for chains.")
   .option("--min <Number>", "The lowest count to print. Stop at this.", 1)
+  .option("--errors", "Show the erorrs so you can fix them.", false)
   .requiredOption("--input <String>", "Input file.")
   .description("Processes different web server logs to determine request chain frequency.")
   .version(0.1);
@@ -252,6 +255,6 @@ OPTS.min = parseInt(OPTS.min);
 
 assert(!isNaN(OPTS.min), `min must be a number, you have ${OPTS.min}`);
 
-const [by_ip, stats] = await parse_logs(OPTS.input);
+const [by_ip, stats] = await parse_logs(OPTS.input, OPTS.errors);
 const chains_sorted = sort_request_chains(by_ip, OPTS.set);
 output_results(OPTS.min, chains_sorted);

02-filter-a-log-file/package-lock.json

@@ -10,6 +10,7 @@
       "license": "BSD",
       "dependencies": {
         "ava": "^4.3.1",
+        "commander": "^9.4.0",
         "date-fns": "^2.29.1",
         "ua-parser-js": "^1.0.2"
       }
@@ -454,6 +455,14 @@
       "resolved": "https://registry.npmjs.org/color-name/-/color-name-1.1.4.tgz",
       "integrity": "sha512-dOy+3AuW3a2wNbZHIuMZpTcgjGuLU/uBL/ubcZF9OXbDo8ff4O8yVp5Bf0efS8uEoYo5q4Fx7dY9OgQGXgAsQA=="
     },
+    "node_modules/commander": {
+      "version": "9.4.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-9.4.0.tgz",
+      "integrity": "sha512-sRPT+umqkz90UA8M1yqYfnHlZA7fF6nSphDtxeywPZ49ysjxDQybzk13CL+mXekDRG92skbcqCLVovuCusNmFw==",
+      "engines": {
+        "node": "^12.20.0 || >=14"
+      }
+    },
     "node_modules/common-path-prefix": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/common-path-prefix/-/common-path-prefix-3.0.0.tgz",
@@ -2139,6 +2148,11 @@
       "resolved": "https://registry.npmjs.org/color-name/-/color-name-1.1.4.tgz",
       "integrity": "sha512-dOy+3AuW3a2wNbZHIuMZpTcgjGuLU/uBL/ubcZF9OXbDo8ff4O8yVp5Bf0efS8uEoYo5q4Fx7dY9OgQGXgAsQA=="
     },
+    "commander": {
+      "version": "9.4.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-9.4.0.tgz",
+      "integrity": "sha512-sRPT+umqkz90UA8M1yqYfnHlZA7fF6nSphDtxeywPZ49ysjxDQybzk13CL+mXekDRG92skbcqCLVovuCusNmFw=="
+    },
     "common-path-prefix": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/common-path-prefix/-/common-path-prefix-3.0.0.tgz",

02-filter-a-log-file/package.json

@@ -11,6 +11,7 @@
   "license": "BSD",
   "dependencies": {
     "ava": "^4.3.1",
+    "commander": "^9.4.0",
     "date-fns": "^2.29.1",
     "ua-parser-js": "^1.0.2"
   }