feat: dns check (#91)

* feat: add dns check * feat: implement the rest of the dns check * feat: add dns metrics * test: add unit tests for dns check methods * feat: add dns check to check register * chore: licensing headers * chore: mv route name to constant * fix: retry on lookup failures * feat: mv metrics to dedicated file * chore: adjust log messages * test: add context cancelation test * chore: rename test functions * chore: rm unused check handlers * test: create ctx for each test * fix: handle injected global targets * chore: PR review * chore: adjust metric names * test: add metric collector tests * chore: rephrase logging message * test: add more set config test cases * docs: adjust metrics godocs * docs: add dns check * docs: add dns check to about this component section * chore: add dns config to helm chart * fix: loader default value runtime config path * fix: use custom dialer * chore: duration metric naming
telekom · Jan 29, 2024 · 585c9c1 · 585c9c1
1 parent 9f1d0d3
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diff --git a/README.md b/README.md
@@ -25,6 +25,9 @@
   - [Check: Latency](#check-latency)
     - [Example configuration](#example-configuration-1)
     - [Latency Metrics](#latency-metrics)
+  - [Check: DNS](#check-dns)
+    - [Example configuration](#example-configuration-2)
+    - [DNS Metrics](#dns-metrics)
 - [API](#api)
 - [Metrics](#metrics)
 - [Code of Conduct](#code-of-conduct)
@@ -38,15 +41,15 @@ executed periodically.
 
 ## About this component
 
-The `sparrow` performs several checks to monitor the health of the infrastructure and network from its point of view.
-The following checks are available:
+The `sparrow` performs several checks to monitor the health of the infrastructure and network from its point of view. The following checks are available:
 
-1. Health check - `health`: The `sparrow` is able to perform an HTTP-based (HTTP/1.1) health check to the provided
-   endpoints.
-   The `sparrow` will expose its own health check endpoint as well.
+1. [Health check](#check-health) - `health`: The `sparrow` is able to perform an HTTP-based (HTTP/1.1) health check to the provided endpoints. The `sparrow` will expose its own health check endpoint as well.
 
-2. Latency check - `latency`: The `sparrow` is able to communicate with other `sparrow` instances to calculate the time
-   a request takes to the target and back. The check is http (HTTP/1.1) based as well.
+2. [Latency check](#check-latency) - `latency`: The `sparrow` is able to communicate with other `sparrow` instances to calculate the time a request takes to the target and back. The check is http (HTTP/1.1) based as well.
+
+3. [DNS check](#check-dns) - `dns`: The `sparrow` is able to perform DNS resolution checks to monitor domain name system performance and reliability. The check has the ability to target specific domains or IPs for monitoring.
+
+Each check is designed to provide comprehensive insights into the various aspects of network and service health, ensuring robust monitoring and quick detection of potential issues.
 
 ## Installation
 
@@ -365,6 +368,57 @@ checks:
   - Description: Latency of targets in seconds
   - Labelled with `target`
 
+### Check: DNS
+
+Available configuration options:
+
+- `checks`
+  - `dns`
+    - `interval` (duration): Interval to perform the DNS check.
+    - `timeout` (duration): Timeout for the DNS check.
+    - `retry`
+      - `count` (integer): Number of retries for the DNS check.
+      - `delay` (duration): Initial delay between retries for the DNS check.
+    - `targets` (list of strings): List of targets to lookup. Needs to be a valid domain or IP. Can be
+      another `sparrow` instance. Automatically updated when a targetManager is configured.
+
+#### Example configuration
+
+```yaml
+checks:
+  dns:
+    interval: 10s
+    timeout: 30s
+    retry:
+      count: 3
+      delay: 1s
+    targets:
+      - www.example.com
+      - www.google.com
+```
+
+#### DNS Metrics
+
+- `sparrow_dns_status`
+  - Type: Gauge
+  - Description: Lookup status of targets
+  - Labelled with `target`
+
+- `sparrow_dns_check_count`
+  - Type: Counter
+  - Description: Count of DNS checks done
+  - Labelled with `target`
+
+- `sparrow_dns_duration`
+  - Type: Gauge
+  - Description: Duration of DNS resolution attempts
+  - Labelled with `target`
+
+- `sparrow_dns_duration`
+  - Type: Histogram
+  - Description: Histogram of response times for DNS checks
+  - Labelled with `target`
+
 ## API
 
 The `sparrow` exposes an API for accessing the results of various checks. Each check registers its own endpoint at `/v1/metrics/{check-name}`. The API's definition is available at `/openapi`.

diff --git a/chart/README.md b/chart/README.md
@@ -62,6 +62,6 @@ A Helm chart to install Sparrow
 | serviceMonitor.interval | string | `"30s"` | Sets the scrape interval |
 | serviceMonitor.labels | object | `{}` | Additional label added to the service Monitor |
 | serviceMonitor.scrapeTimeout | string | `"5s"` | Sets the scrape timeout |
-| sparrowConfig | object | `{"loader":{"path":"/config/checksConfig.yaml","type":"file"},"name":"sparrow.com"}` | Sparrow configuration read on startup see: https://github.com/caas-team/sparrow/blob/main/docs/sparrow_run.md |
+| sparrowConfig | object | `{"loader":{"path":"/config/checks.yaml","type":"file"},"name":"sparrow.com"}` | Sparrow configuration read on startup see: https://github.com/caas-team/sparrow/blob/main/docs/sparrow_run.md |
 | tolerations | list | `[]` |  |
 
diff --git a/chart/values.yaml b/chart/values.yaml
@@ -111,7 +111,7 @@ sparrowConfig:
   name: sparrow.com
   loader:
     type: file
-    path: /config/checksConfig.yaml
+    path: /config/checks.yaml
 # name: the-sparrow.com
 # api:
 #   address:
@@ -139,25 +139,34 @@ sparrowConfig:
 # see: https://github.com/caas-team/sparrow?tab=readme-ov-file#checks
 checksConfig:
   checks: {}
-# checks:
-#   health:
-#     interval: 15s
-#     timeout: 10s
-#     retry:
-#       count: 3
-#       delay: 1s
-#     targets:
-#       - "https://www.example.com/"
-#       - "https://www.google.com/"
-#   latency:
-#     interval: 15s
-#     timeout: 30s
-#     retry:
-#       count: 3
-#       delay: 2s
-#     targets:
-#       - https://example.com/
-#       - https://google.com/
+  # checks:
+  #   health:
+  #     interval: 15s
+  #     timeout: 10s
+  #     retry:
+  #       count: 3
+  #       delay: 1s
+  #     targets:
+  #       - "https://www.example.com/"
+  #       - "https://www.google.com/"
+  #   latency:
+  #     interval: 15s
+  #     timeout: 30s
+  #     retry:
+  #       count: 3
+  #       delay: 2s
+  #     targets:
+  #       - https://example.com/
+  #       - https://google.com/
+  #   dns:
+  #     interval: 10s
+  #     timeout: 30s
+  #     retry:
+  #       count: 5
+  #       delay: 1s
+  #     targets:
+  #       - www.example.com
+  #       - www.google.com
 
 # -- Configure a service monitor for prometheus-operator
 serviceMonitor:

diff --git a/go.mod b/go.mod
@@ -47,7 +47,7 @@ require (
 	github.com/subosito/gotenv v1.6.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa // indirect
-	golang.org/x/sys v0.15.0 // indirect
+	golang.org/x/sys v0.16.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect

diff --git a/go.sum b/go.sum
@@ -106,8 +106,8 @@ go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN8
 golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa h1:FRnLl4eNAQl8hwxVVC17teOw8kdjVDVAiFMtgUdTSRQ=
 golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa/go.mod h1:zk2irFbV9DP96SEBUUAy67IdHUaZuSnrz1n472HUCLE=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=
-golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
+golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

diff --git a/pkg/checks/checks.go b/pkg/checks/checks.go
@@ -24,7 +24,6 @@ import (
 	"github.com/getkin/kin-openapi/openapi3"
 	"github.com/prometheus/client_golang/prometheus"
 
-	"github.com/caas-team/sparrow/pkg/api"
 	"github.com/caas-team/sparrow/pkg/checks/types"
 )
 
@@ -48,10 +47,6 @@ type Check interface {
 	SetConfig(ctx context.Context, config any) error
 	// Schema returns an openapi3.SchemaRef of the result type returned by the check
 	Schema() (*openapi3.SchemaRef, error)
-	// RegisterHandler Allows the check to register a handler on sparrows http server at runtime
-	RegisterHandler(ctx context.Context, router *api.RoutingTree)
-	// DeregisterHandler allows the check to deregister a handler on sparrows http server at runtime
-	DeregisterHandler(ctx context.Context, router *api.RoutingTree)
 	// GetMetricCollectors allows the check to provide prometheus metric collectors
 	GetMetricCollectors() []prometheus.Collector
 }
diff --git a/pkg/checks/checks_moq.go b/pkg/checks/checks_moq.go