From 33a7c9d0cff6a783bfed106d322a9c8ce876c633 Mon Sep 17 00:00:00 2001
From: Lars Strojny <lars@strojny.net>
Date: Sun, 8 Jan 2023 17:21:41 +0100
Subject: [PATCH] Terminate output with a linefeed

---
 src/prometheus.ts                   | 18 ++++++++++--------
 tests/adapters/http/fastify.test.ts |  2 ++
 tests/prometheus.test.ts            | 27 ++++++++++++++++++---------
 3 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/src/prometheus.ts b/src/prometheus.ts
index 798036f..e86371a 100644
--- a/src/prometheus.ts
+++ b/src/prometheus.ts
@@ -13,14 +13,16 @@ export class MetricsRenderer {
     }
 
     render(metrics: Metric[]): string {
-        return Object.entries(metrics.sort().group((metric) => this.metricName(metric.name)))
-            .map(([name, metrics]) => {
-                return [
-                    `# TYPE ${name} ${name.endsWith('_total') ? 'counter' : 'gauge'}`,
-                    metrics.map((metric) => this.formatMetric(metric)).join('\n'),
-                ].join('\n')
-            })
-            .join('\n\n')
+        return (
+            Object.entries(metrics.sort().group((metric) => this.metricName(metric.name)))
+                .map(([name, metrics]) => {
+                    return [
+                        `# TYPE ${name} ${name.endsWith('_total') ? 'counter' : 'gauge'}`,
+                        metrics.map((metric) => this.formatMetric(metric)).join('\n'),
+                    ].join('\n')
+                })
+                .join('\n\n') + '\n'
+        )
     }
 
     private formatMetric(metric: Metric): string {
diff --git a/tests/adapters/http/fastify.test.ts b/tests/adapters/http/fastify.test.ts
index df3beaa..d94f5b3 100644
--- a/tests/adapters/http/fastify.test.ts
+++ b/tests/adapters/http/fastify.test.ts
@@ -74,6 +74,7 @@ describe('Fastify HTTP adapter', () => {
                     '',
                     '# TYPE homebridge_something_total counter',
                     'homebridge_something_total{name="counter"} 100 1577836800000',
+                    '',
                 ].join('\n'),
             )
     })
@@ -121,6 +122,7 @@ describe('Fastify HTTP adapter', () => {
                     '',
                     '# TYPE homebridge_something_total counter',
                     'homebridge_something_total{name="counter"} 100 1577836800000',
+                    '',
                 ].join('\n'),
             )
     })
diff --git a/tests/prometheus.test.ts b/tests/prometheus.test.ts
index 0ff6c9c..33d48b7 100644
--- a/tests/prometheus.test.ts
+++ b/tests/prometheus.test.ts
@@ -8,14 +8,16 @@ describe('Render prometheus metrics', () => {
     test('Renders simple metric', () => {
         expect(renderer.render([new Metric('metric', 0.000001)])).toEqual(
             `# TYPE prefix_metric gauge
-prefix_metric 0.000001`,
+prefix_metric 0.000001
+`,
         )
     })
 
     test('Renders simple metric with timestamp', () => {
         expect(renderer.render([new Metric('metric', 0.000001, new Date('2000-01-01 00:00:00 UTC'))])).toEqual(
             `# TYPE prefix_metric gauge
-prefix_metric 0.000001 946684800000`,
+prefix_metric 0.000001 946684800000
+`,
         )
     })
 
@@ -26,7 +28,8 @@ prefix_metric 0.000001 946684800000`,
             ]),
         ).toEqual(
             `# TYPE prefix_metric gauge
-prefix_metric{label="Some Label"} 0.000001 946684800000`,
+prefix_metric{label="Some Label"} 0.000001 946684800000
+`,
         )
     })
 
@@ -38,7 +41,8 @@ prefix_metric{label="Some Label"} 0.000001 946684800000`,
                 ]),
             ).toEqual(
                 `# TYPE prefix_some_metric_total counter
-prefix_some_metric_total{label="Some Label"} 42 946684800000`,
+prefix_some_metric_total{label="Some Label"} 42 946684800000
+`,
             )
         }
     })
@@ -56,35 +60,40 @@ prefix_some_gauge 10 946684800000
 prefix_some_gauge 20 946684800000
 
 # TYPE prefix_another_gauge gauge
-prefix_another_gauge 30 946684800000`,
+prefix_another_gauge 30 946684800000
+`,
         )
     })
 
     test('Sanitizes metric names', () => {
         expect(renderer.render([new Metric('mätric name', 0)])).toEqual(
             `# TYPE prefix_m_tric_name gauge
-prefix_m_tric_name 0`,
+prefix_m_tric_name 0
+`,
         )
     })
 
     test('Sanitizes label names', () => {
         expect(renderer.render([new Metric('metric', 0, null, { 'yet another label': 'foo' })])).toEqual(
             `# TYPE prefix_metric gauge
-prefix_metric{yet_another_label="foo"} 0`,
+prefix_metric{yet_another_label="foo"} 0
+`,
         )
     })
 
     test('Escapes newlines in attribute value', () => {
         expect(renderer.render([new Metric('metric', 0, null, { label: 'foo\nbar' })])).toEqual(
             `# TYPE prefix_metric gauge
-prefix_metric{label="foo\\nbar"} 0`,
+prefix_metric{label="foo\\nbar"} 0
+`,
         )
     })
 
     test('Escapes quotes in attribute value', () => {
         expect(renderer.render([new Metric('metric', 0, null, { label: 'foo"bar' })])).toEqual(
             `# TYPE prefix_metric gauge
-prefix_metric{label="foo\\"bar"} 0`,
+prefix_metric{label="foo\\"bar"} 0
+`,
         )
     })
 })