From 24b4247b7665800a0b80d578f037558d7f578d98 Mon Sep 17 00:00:00 2001
From: Ranko Orlic <ranko@aquila-solutions.com>
Date: Tue, 14 Nov 2023 12:32:44 +0100
Subject: [PATCH] chore: allow retries

---
 Dockerfile   |  6 +++++-
 README.md    |  2 ++
 src/index.ts | 43 +++++++++++++++++++++++++++++++++----------
 3 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index ce8254b..ba359b9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -41,7 +41,11 @@ ARG MIMETYPE=
 ENV MIMETYPE=${MIMETYPE}
 ARG RANGE=
 ENV RANGE=${RANGE}
+ARG MAX_RETRIES=5
+ENV MAX_RETRIES=${MAX_RETRIES}
+ARG RETRY_TIMEOUT=10
+ENV RETRY_TIMEOUT=${RETRY_TIMEOUT}
 ## set start command
 ENTRYPOINT ["/usr/bin/dumb-init", "--"]
 USER node
-CMD ["sh", "-c", "node index.js --silent=${SILENT} --range=${RANGE} --mimeType=\"${MIMETYPE}\" --targetUrl=${TARGETURL} --cron=\"${CRON}\" --template=\"${TEMPLATE}\" --templateFile=${TEMPLATEFILE}"]
+CMD ["sh", "-c", "node index.js --silent=${SILENT} --retryTimeout=${RETRY_TIMEOUT} --maxRFetries=${MAX_RETRIES} --range=${RANGE} --mimeType=\"${MIMETYPE}\" --targetUrl=${TARGETURL} --cron=\"${CRON}\" --template=\"${TEMPLATE}\" --templateFile=${TEMPLATEFILE}"]
diff --git a/README.md b/README.md
index 1795696..759f58f 100644
--- a/README.md
+++ b/README.md
@@ -49,6 +49,8 @@ The generator takes the following command line arguments:
 * `--template='<content>'` allows to provide the template on the command line, no default (if not provided, you MUST provide `--templateFile`)
 * `--templateFile=<partial-or-full-pathname>` allows to provide the template in a file, no default (if not provided, you MUST provide `--template`)
 * `--range=<range>` allows to create a range of values (1 to `<range>`) on every tick instead of an increasing index
+* `--maxRetries=<number>` allows to retry some (possibly retryable) HTTP status codes (429, 500 & 503) a maximum number of times
+* `--retryTimeout=<ms>` the amount of time (in milliseconds) to wait between retrying to send the message again
 
 The template or template file should simply contain a message with mustache variables (between `{{` and `}}`). E.g.:
 ```json
diff --git a/src/index.ts b/src/index.ts
index 7644c42..588ba8a 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -10,28 +10,51 @@ if (!silent) console.debug("Arguments: ", args);
 
 const cron = args['cron'] || '* * * * * *';
 const mimeType = args['mimeType'];
+const maxRetries = Number.parseInt(args['maxRetries'] || '5');
+const retryTimeout = Number.parseInt(args['retryTimeout'] || '10');
 let template: string = args['template'] || (args['templateFile'] && readFileSync(args['templateFile'], {encoding: 'utf8'}));
 if (!template) throw new Error('Missing template or templateFile');
 
 const generator: Generator = new Generator(template);
 const range = Number.parseInt(args['range'] || '0');
+const nonFatalHttpCodes : number[] = [429, 500, 503];
+const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
+let messageCount = 0;
 
 const job = new CronJob(cron, async () => {
     const timestamp = new Date().toISOString();
     const messages = range ? generator.createRange(range) : [generator.createNext()];
+    const targetUrl = args['targetUrl'] || (existsSync('./TARGETURL') && readFileSync('./TARGETURL', 'utf-8').trimEnd());
     for await (const body of messages) {
-        const targetUrl = args['targetUrl'] || (existsSync('./TARGETURL') && readFileSync('./TARGETURL', 'utf-8').trimEnd());
+        ++messageCount;
+
         if (targetUrl) {
             if (!mimeType) throw new Error('Missing mimeType');
-
-            if (!silent) console.debug(`Sending to '${targetUrl}':`, body);
-            const response = await fetch(targetUrl, {
-                method: 'post',
-                body: body,
-                headers: {'Content-Type': mimeType}
-            });
-            if (!silent) console.debug(`Response: ${response.statusText}`);
-            if (silent) console.info(`[${timestamp}] POST ${targetUrl} ${response.status}`);
+            let retry = false;
+            let retries = 0;
+            do {
+                try {
+                    if (!silent) {
+                        const msg = retry ? `Retrying (${retries} of ${maxRetries}) send` : "Sending";
+                        console.debug(`${msg} message ${messageCount} to ${targetUrl}`, body);
+                    }
+                    const response = await fetch(targetUrl, {
+                        method: 'post',
+                        body: body,
+                        headers: {'Content-Type': mimeType}
+                    });
+                    if (!silent) console.debug(`Response: ${response.statusText}`);
+                    if (silent) {
+                        const msg = retry ? ` (retry ${retries} of ${maxRetries})` : ' ';
+                        console.info(`[${timestamp}] POST ${targetUrl} (msg: ${messageCount}) ${response.status}${msg}`);
+                    }
+                    retry = nonFatalHttpCodes.includes(response.status);
+                } catch (error) {
+                    const msg = error instanceof Error ? `${error.name}: ${error.message}, reason: ${error.cause}` : String(error);
+                    console.error(`ERROR: cannot POST to ${targetUrl} because: ${msg}`);
+                    retry = true;
+                }
+            } while (retry && (++retries <= maxRetries) && (await sleep(retryTimeout), true));
         } else { // if no targetUrl specified, send to console
             console.info(body);
         }