misc exit features: (#366)

- if interrupted (via signal or due to limits) and not finished, return error code 11 to indicate interruption
- allow stopping single instances with hset '<crawlid>:stopone' uid (similar to status)
- deliberate stop via redis not considered interruption (exit 0)

crawler.js

@@ -163,7 +163,7 @@ export class Crawler {
       } catch (e) {
         //logger.fatal("Unable to connect to state store Redis: " + redisUrl);
         logger.warn(`Waiting for redis at ${redisUrl}`, {}, "state");
-        await sleep(3);
+        await sleep(1);
       }
     }
 
@@ -304,12 +304,16 @@ export class Crawler {
   async run() {
     await this.bootstrap();
 
-    let status;
+    let status = "done";
     let exitCode = 0;
 
     try {
       await this.crawl();
-      status = (!this.interrupted ? "done" : "interrupted");
+      const finished = await this.crawlState.isFinished();
+      if (this.interrupted && !finished) {
+        status = "interrupted";
+        exitCode = 11;
+      }
     } catch(e) {
       logger.error("Crawl failed", e);
       exitCode = 9;

util/state.js

@@ -207,7 +207,15 @@ return 0;
   }
 
   async isCrawlStopped() {
-    return await this.redis.get(`${this.key}:stopping`) === "1";
+    if (await this.redis.get(`${this.key}:stopping`) === "1") {
+      return true;
+    }
+
+    if (await this.redis.hget(`${this.key}:stopone`, this.uid) === "1") {
+      return true;
+    }
+
+    return false;
   }
 
   // note: not currently called in crawler, but could be