opossum - npm Package Compare versions

Comparing version 1.1.0 to 1.2.0

CHANGELOG.md

@@ -5,2 +5,20 @@ # Change Log
 
+<a name="1.2.0"></a>
+# [1.2.0](https://github.com/bucharest-gold/opossum/compare/v1.1.0...v1.2.0) (2017-06-20)
+
+
+### Bug Fixes
+
+* semaphore is part of the class ([0faa766](https://github.com/bucharest-gold/opossum/commit/0faa766))
+* semaphore released with timeout ([e181d43](https://github.com/bucharest-gold/opossum/commit/e181d43))
+
+
+### Features
+
+* implement our own semaphore ([4d0c057](https://github.com/bucharest-gold/opossum/commit/4d0c057))
+* include semaphore rejects in hystrix stats ([2c326cc](https://github.com/bucharest-gold/opossum/commit/2c326cc))
+* semaphore added ([e62a569](https://github.com/bucharest-gold/opossum/commit/e62a569))
+
+
+
 <a name="1.1.0"></a>
@@ -7,0 +25,0 @@ # [1.1.0](https://github.com/bucharest-gold/opossum/compare/v1.0.0...v1.1.0) (2017-06-06)

lib/circuit.js

@@ -6,2 +6,3 @@ 'use strict';
 const HystrixStats = require('./hystrix-stats');
+const Semaphore = require('./semaphore');
 
@@ -46,2 +47,5 @@ const STATE = Symbol('state');
  *  If they are disabled, all summary statistics (mean, percentiles) are returned as -1.
+ * @param options.capacity the number of concurrent requests allowed. If the number of
+ * currently executing function calls is equal to options.capacity, further calls to `fire()`
+ * are rejected until at least one of the current requests completes.
  */
@@ -55,2 +59,4 @@ class CircuitBreaker extends EventEmitter {
     this.options.rollingPercentilesEnabled = options.rollingPercentilesEnabled !== false;
+    this.options.capacity = typeof options.capacity === 'number' ? options.capacity : 10;
+    this.semaphore = new Semaphore(this.options.capacity);
 
@@ -82,2 +88,3 @@ this[STATUS] = new Status(this.options);
     this.on('close', _ => this[STATUS].close());
+    this.on('semaphore-locked', increment('semaphoreRejections'));
 
@@ -283,43 +290,55 @@ /**
       const latencyStartTime = Date.now();
-      timeout = setTimeout(
-        () => {
-          timeoutError = true;
-          const error = new Error(`Timed out after ${this.options.timeout}ms`);
-          error.code = 'ETIMEDOUT';
-          /**
-           * Emitted when the circuit breaker action takes longer than `options.timeout`
-           * @event CircuitBreaker#timeout
-           */
-          const latency = Date.now() - latencyStartTime;
-          this.emit('timeout', error, latency);
-          resolve(handleError(error, this, timeout, args, latency, resolve, reject));
-        }, this.options.timeout);
+      if (this.semaphore.test()) {
+        timeout = setTimeout(
+          () => {
+            timeoutError = true;
+            const error = new Error(`Timed out after ${this.options.timeout}ms`);
+            error.code = 'ETIMEDOUT';
+            /**
+             * Emitted when the circuit breaker action takes longer than `options.timeout`
+             * @event CircuitBreaker#timeout
+             */
+            const latency = Date.now() - latencyStartTime;
+            this.semaphore.release();
+            this.emit('timeout', error, latency);
+            resolve(handleError(error, this, timeout, args, latency, resolve, reject));
+          }, this.options.timeout);
 
-      try {
-        const result = this.action.apply(this.action, args);
-        const promise = (typeof result.then === 'function')
-          ? result
-          : Promise.resolve(result);
+        try {
+          const result = this.action.apply(this.action, args);
+          const promise = (typeof result.then === 'function')
+            ? result
+            : Promise.resolve(result);
 
-        promise.then((result) => {
-          if (!timeoutError) {
-            clearTimeout(timeout);
-            /**
-             * Emitted when the circuit breaker action succeeds
-             * @event CircuitBreaker#success
-             */
-            this.emit('success', result, (Date.now() - latencyStartTime));
-            resolve(result);
-            if (this.options.cache) {
-              CACHE.set(this, promise);
+          promise.then((result) => {
+            if (!timeoutError) {
+              clearTimeout(timeout);
+              /**
+               * Emitted when the circuit breaker action succeeds
+               * @event CircuitBreaker#success
+               */
+              this.emit('success', result, (Date.now() - latencyStartTime));
+              this.semaphore.release();
+              resolve(result);
+              if (this.options.cache) {
+                CACHE.set(this, promise);
+              }
             }
-          }
-        })
-        .catch((error) => {
-          const latencyEndTime = Date.now() - latencyStartTime;
-          handleError(error, this, timeout, args, latencyEndTime, resolve, reject);
-        });
-      } catch (error) {
+          })
+          .catch((error) => {
+            this.semaphore.release();
+            const latencyEndTime = Date.now() - latencyStartTime;
+            handleError(error, this, timeout, args, latencyEndTime, resolve, reject);
+          });
+        } catch (error) {
+          this.semaphore.release();
+          const latency = Date.now() - latencyStartTime;
+          handleError(error, this, timeout, args, latency, resolve, reject);
+        }
+      } else {
         const latency = Date.now() - latencyStartTime;
-        handleError(error, this, timeout, args, latency, resolve, reject);
+        const err = new Error('Semaphore locked');
+        err.code = 'ESEMLOCKED';
+        this.emit('semaphore-locked', err, latency);
+        handleError(err, this, timeout, args, latency, resolve, reject);
       }
@@ -326,0 +345,0 @@ });

lib/hystrix-formatter.js

@@ -26,3 +26,3 @@ 'use strict';
   json.rollingCountResponsesFromCache = stats.cacheHits;
-  json.rollingCountSemaphoreRejected = stats.rejects;
+  json.rollingCountSemaphoreRejected = stats.semaphoreRejections;
   json.rollingCountShortCircuited = stats.rejects;
@@ -71,4 +71,4 @@ json.rollingCountSuccess = stats.successes;
   json.propertyValue_executionIsolationThreadPoolKeyOverride = null;
-  json.propertyValue_executionIsolationSemaphoreMaxConcurrentRequests = 10;
-  json.propertyValue_fallbackIsolationSemaphoreMaxConcurrentRequests = 10;
+  json.propertyValue_executionIsolationSemaphoreMaxConcurrentRequests = stats.options.capacity;
+  json.propertyValue_fallbackIsolationSemaphoreMaxConcurrentRequests = stats.options.capacity;
   json.propertyValue_metricsRollingStatisticalWindowInMilliseconds = 10000;
@@ -75,0 +75,0 @@ json.propertyValue_requestCacheEnabled = stats.options.cache || false;

lib/status.js

@@ -167,2 +167,3 @@ 'use strict';
   cacheMisses: 0,
+  semaphoreRejections: 0,
   percentiles: {},
@@ -169,0 +170,0 @@ latencyTimes: []

package.json

 {
   "name": "opossum",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "author": "Red Hat, Inc.",
@@ -75,4 +75,3 @@ "license": "Apache-2.0",
     "fail-fast"
-  ],
-  "dependencies": {}
+  ]
 }

README.md

@@ -153,2 +153,3 @@ # opossum
 * `fallback` - emitted when the breaker has a fallback function and executes it
+* `semaphore-locked` - emitted when the breaker is at capacity and cannot execute the request
 
@@ -155,0 +156,0 @@ Handling events gives a greater level of control over your application behavior.

New alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Fixed alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

319783

increased by6.97%

Number of package files

14

increased by7.69%

Lines of code

6456

increased by7.14%

Number of lines in readme file

229

increased by0.44%

No dependency changes