Merge branch 'integration-tests' into 'master'

Add an integration test with a simple HTTP probe

See merge request !14

.gitlab-ci.yml

 include:
   - "https://git.autistici.org/pipelines/containers/raw/master/common.yml"
   - "https://git.autistici.org/ai3/docker/test/golang/raw/master/ci.yml"
+
+ctest-http:
+  image: registry.git.autistici.org/ai3/docker/test/float-like-podman:master
+  stage: container-test
+  tags: [podman]
+  variables:
+    URL: https://www.incal.net/
+  script:
+    - sed -e "s,@URL@,$URL,g" < test/http/config.json > config.json
+    - with-container --mount=type=bind,source=$PWD/config.json,destination=/etc/service-prober.json --env=SERVICE_PROBER_CONFIG=/etc/service-prober.json --env=SERVICE_PROBER_HTTP_ADDR=:5521 --expose=5521 $IMAGE_TAG ./test/test.sh

cmd/service-prober/main.go

@@ -21,12 +21,19 @@ import (
 	_ "git.autistici.org/ai3/tools/service-prober/probes/openvpn"
 )
 
+func getenvDef(key, def string) string {
+	if s := os.Getenv(key); s != "" {
+		return s
+	}
+	return def
+}
+
 var (
-	config      = flag.String("config", "", "configuration file `path`")
+	config      = flag.String("config", os.Getenv("SERVICE_PROBER_CONFIG"), "configuration file `path`")
 	oneshot     = flag.Bool("oneshot", false, "run just one shot and exit")
 	validate    = flag.Bool("validate", false, "just validate the configuration syntax")
-	only        = flag.String("only", "", "only run probes with names matching this `regex`")
-	httpAddr    = flag.String("http-addr", ":5522", "`address` for the HTTP server")
+	only        = flag.String("only", os.Getenv("SERVICE_PROBER_ONLY"), "only run probes with names matching this `regex`")
+	httpAddr    = flag.String("http-addr", getenvDef("SERVICE_PROBER_HTTP_ADDR", ":5522"), "`address` for the HTTP server")
 	keepResults = flag.Int("keep-results", 100, "keep `N` results of past probes in memory")
 )
 

test/http/config.json

+{
+    "vars": {},
+    "probes": [
+        {
+            "type": "http",
+            "name": "test",
+            "interval": "1m",
+            "timeout": "1m",
+            "params": {
+                "script": [
+                    {
+                        "type": "open",
+                        "url": "@URL@",
+                        "expected_url": "@URL@"
+                    }
+                ]
+            }
+        }
+    ]
+}

test/test.sh

+#!/bin/sh
+
+value=$(curl -sf http://localhost:5521/metrics | awk '/^probe_success/ {print $2}')
+case "$value" in
+    1)
+        echo "success!" >&2
+        exit 0
+        ;;
+
+    0)
+        echo "probe has failed" >&2
+        exit 2
+        ;;
+esac
+
+# No probe_success value, or connection error. Retry.
+exit 1