feat(common.http): Add support for connecting over unix-socket (#14103)

docs/LICENSE_OF_DEPENDENCIES.md

@@ -281,6 +281,7 @@ following works:
 - github.com/opentracing/opentracing-go [Apache License 2.0](https://github.com/opentracing/opentracing-go/blob/master/LICENSE)
 - github.com/p4lang/p4runtime [Apache License 2.0](https://github.com/p4lang/p4runtime/blob/main/LICENSE)
 - github.com/pborman/ansi [BSD 3-Clause "New" or "Revised" License](https://github.com/pborman/ansi/blob/master/LICENSE)
+- github.com/peterbourgon/unixtransport [Apache License 2.0](https://github.com/peterbourgon/unixtransport/blob/main/LICENSE)
 - github.com/philhofer/fwd [MIT License](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 - github.com/pierrec/lz4 [BSD 3-Clause "New" or "Revised" License](https://github.com/pierrec/lz4/blob/master/LICENSE)
 - github.com/pion/dtls [MIT License](https://github.com/pion/dtls/blob/master/LICENSES/MIT.txt)

go.mod

@@ -147,6 +147,7 @@ require (
 	github.com/openzipkin/zipkin-go v0.4.1
 	github.com/p4lang/p4runtime v1.3.0
 	github.com/pborman/ansi v1.0.0
+	github.com/peterbourgon/unixtransport v0.0.3
 	github.com/pion/dtls/v2 v2.2.7
 	github.com/prometheus-community/pro-bing v0.3.0
 	github.com/prometheus/client_golang v1.16.0

go.sum

@@ -1094,6 +1094,7 @@ github.com/microsoft/go-mssqldb v1.5.0/go.mod h1:lmWsjHD8XX/Txr0f8ZqgbEZSC+BZjmE
 github.com/miekg/dns v1.0.14/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
 github.com/miekg/dns v1.1.26/go.mod h1:bPDLeHnStXmXAq1m/Ch/hvfNHr14JKNPMBo3VZKjuso=
 github.com/miekg/dns v1.1.41/go.mod h1:p6aan82bvRIyn+zDIv9xYNUpwa73JcSh9BKwknJysuI=
+github.com/miekg/dns v1.1.54/go.mod h1:uInx36IzPl7FYnDcMeVWxj9byh7DutNykX4G9Sj60FY=
 github.com/miekg/dns v1.1.56 h1:5imZaSeoRNvpM9SzWNhEcP9QliKiz20/dA2QabIGVnE=
 github.com/miekg/dns v1.1.56/go.mod h1:cRm6Oo2C8TY9ZS/TqsSrseAcncm74lfK5G+ikN2SWWY=
 github.com/mikioh/ipaddr v0.0.0-20190404000644-d465c8ab6721 h1:RlZweED6sbSArvlE924+mUcZuXKLBHA35U7LN621Bws=
@@ -1181,6 +1182,7 @@ github.com/nwaples/tacplus v0.0.3/go.mod h1:y5ZA9N5V2JbmwO766S+ET9zuu5FtL1OtdfBC
 github.com/nxadm/tail v1.4.4/go.mod h1:kenIhsEOeOJmVchQTgglprH7qJGnHDVpk1VPCcaMI8A=
 github.com/nxadm/tail v1.4.8 h1:nPr65rt6Y5JFSKQO7qToXr7pePgD6Gwiw05lkbyAQTE=
 github.com/nxadm/tail v1.4.8/go.mod h1:+ncqLTQzXmGhMZNUePPaPqPvBxHAIsmXswZKocGu+AU=
+github.com/oklog/run v1.1.0/go.mod h1:sVPdnTZT1zYwAJeCMu2Th4T21pA3FPOQRfWjQlk7DVU=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
 github.com/oliveagle/jsonpath v0.0.0-20180606110733-2e52cf6e6852/go.mod h1:eqOVx5Vwu4gd2mmMZvVZsgIqNSaW3xxRThUJ0k/TPk4=
 github.com/olivere/elastic v6.2.37+incompatible h1:UfSGJem5czY+x/LqxgeCBgjDn6St+z8OnsCuxwD3L0U=
@@ -1252,6 +1254,10 @@ github.com/pborman/uuid v1.2.1 h1:+ZZIw58t/ozdjRaXh/3awHfmWRbzYxJoAdNJxe/3pvw=
 github.com/pborman/uuid v1.2.1/go.mod h1:X/NO0urCmaxf9VXbdlT7C2Yzkj2IKimNn4k+gtPdI/k=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/pelletier/go-toml v1.8.1/go.mod h1:T2/BmBdy8dvIRq1a/8aqjN41wvWlN4lrapLU/GW4pbc=
+github.com/pelletier/go-toml v1.9.5/go.mod h1:u1nR/EPcESfeI/szUZKdtJ0xRNbUoANCkoOuaOx1Y+c=
+github.com/peterbourgon/ff/v3 v3.3.1/go.mod h1:zjJVUhx+twciwfDl0zBcFzl4dW8axCRyXE/eKY9RztQ=
+github.com/peterbourgon/unixtransport v0.0.3 h1:NmGkSb+OOIeN2rNR+fF+F5kymwRy9VignywyDdtRrpc=
+github.com/peterbourgon/unixtransport v0.0.3/go.mod h1:o8aUkOCa8W/BIXpi15uKvbSabjtBh0JhSOJGSfoOhAU=
 github.com/philhofer/fwd v1.1.2 h1:bnDivRJ1EWPjUIRXV5KfORO897HTbpFAQddBdE8t7Gw=
 github.com/philhofer/fwd v1.1.2/go.mod h1:qkPdfjR2SIEbspLqpe1tO4n5yICnr2DY7mqEx2tUTP0=
 github.com/pierrec/lz4 v2.0.5+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
@@ -1927,6 +1933,7 @@ golang.org/x/tools v0.1.5/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
 golang.org/x/tools v0.1.7/go.mod h1:LGqMHiF4EqQNHR1JncWGqT5BVaXmza+X+BDGol+dOxo=
 golang.org/x/tools v0.1.8/go.mod h1:nABZi5QlRsZVlzPpHl034qft6wpY4eDcsTt5AaioBiU=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/tools v0.3.0/go.mod h1:/rWhSS2+zyEVwoJf8YAX6L2f0ntZ7Kn/mGgAWcipA5k=
 golang.org/x/tools v0.4.0/go.mod h1:UE5sM2OK9E/d67R0ANs2xJizIymRP5gJU295PvKXxjQ=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
 golang.org/x/tools v0.13.0 h1:Iey4qkscZuv0VvIt8E0neZjtPVQFSc870HQ448QgEmQ=

plugins/common/http/config.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/benbjohnson/clock"
+	"github.com/peterbourgon/unixtransport"
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/config"
@@ -48,6 +49,9 @@ func (h *HTTPClientConfig) CreateClient(ctx context.Context, log telegraf.Logger
 		MaxIdleConnsPerHost: h.MaxIdleConnsPerHost,
 	}
 
+	// Register "http+unix" and "https+unix" protocol handler.
+	unixtransport.Register(transport)
+
 	timeout := h.Timeout
 	if timeout == 0 {
 		timeout = config.Duration(time.Second * 5)

plugins/inputs/http/README.md

@@ -29,9 +29,10 @@ to use them.
 ```toml @sample.conf
 # Read formatted metrics from one or more HTTP endpoints
 [[inputs.http]]
-  ## One or more URLs from which to read formatted metrics
+  ## One or more URLs from which to read formatted metrics.
   urls = [
-    "http://localhost/metrics"
+    "http://localhost/metrics",
+    "http+unix:///run/user/420/podman/podman.sock:/d/v4.0.0/libpod/pods/json"
   ]
 
   ## HTTP method
@@ -105,6 +106,17 @@ to use them.
 
 ```
 
+HTTP requests over Unix domain sockets can be specified via the "http+unix" or
+"https+unix" schemes.
+Request URLs should have the following form:
+
+```text
+http+unix:///path/to/service.sock:/api/endpoint
+```
+
+Note: The path to the Unix domain socket and the request endpoint are separated
+by a colon (":").
+
 ## Example Output
 
 This example output was taken from [this instructional article][1].

plugins/inputs/http/http_test.go

@@ -4,9 +4,14 @@ import (
 	"compress/gzip"
 	"fmt"
 	"io"
+	"math/rand"
+	"net"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
 	"testing"
 	"time"
 
@@ -446,3 +451,74 @@ func TestHTTPWithCSVFormat(t *testing.T) {
 	require.NoError(t, acc.GatherError(plugin.Gather))
 	testutil.RequireMetricsEqual(t, expected, acc.GetTelegrafMetrics(), testutil.IgnoreTime())
 }
+
+const (
+	httpOverUnixScheme = "http+unix"
+)
+
+func TestConnectionOverUnixSocket(t *testing.T) {
+	ts := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/data" {
+			w.Header().Set("Content-Type", "text/csv")
+			_, _ = w.Write([]byte(simpleCSVWithHeader))
+		} else {
+			w.WriteHeader(http.StatusNotFound)
+		}
+	}))
+
+	unixListenAddr := filepath.Join(os.TempDir(), fmt.Sprintf("httptestserver.%d.sock", rand.Intn(1_000_000)))
+	t.Cleanup(func() { os.Remove(unixListenAddr) })
+
+	unixListener, err := net.Listen("unix", unixListenAddr)
+	require.NoError(t, err)
+
+	ts.Listener = unixListener
+	ts.Start()
+	defer ts.Close()
+
+	// NOTE: Remove ":" from windows filepath and replace all "\" with "/".
+	//       This is *required* so that the unix socket path plays well with unixtransport.
+	replacer := strings.NewReplacer(":", "", "\\", "/")
+	sockPath := replacer.Replace(unixListenAddr)
+
+	address := fmt.Sprintf("%s://%s:/data", httpOverUnixScheme, sockPath)
+	plugin := &httpplugin.HTTP{
+		URLs: []string{address},
+		Log:  testutil.Logger{},
+	}
+
+	plugin.SetParserFunc(func() (telegraf.Parser, error) {
+		parser := &csv.Parser{
+			MetricName:  "metricName",
+			SkipRows:    3,
+			ColumnNames: []string{"a", "b", "c"},
+			TagColumns:  []string{"c"},
+		}
+		err := parser.Init()
+		return parser, err
+	})
+
+	expected := []telegraf.Metric{
+		testutil.MustMetric("metricName",
+			map[string]string{
+				"url": address,
+				"c":   "ok",
+			},
+			map[string]interface{}{
+				"a": 1.2,
+				"b": 3.1415,
+			},
+			time.Unix(22000, 0),
+		),
+	}
+
+	var acc testutil.Accumulator
+	require.NoError(t, plugin.Init())
+	require.NoError(t, acc.GatherError(plugin.Gather))
+	testutil.RequireMetricsEqual(t, expected, acc.GetTelegrafMetrics(), testutil.IgnoreTime())
+
+	// Run the parser a second time to test for correct stateful handling
+	acc.ClearMetrics()
+	require.NoError(t, acc.GatherError(plugin.Gather))
+	testutil.RequireMetricsEqual(t, expected, acc.GetTelegrafMetrics(), testutil.IgnoreTime())
+}

plugins/inputs/http/sample.conf

@@ -1,8 +1,9 @@
 # Read formatted metrics from one or more HTTP endpoints
 [[inputs.http]]
-  ## One or more URLs from which to read formatted metrics
+  ## One or more URLs from which to read formatted metrics.
   urls = [
-    "http://localhost/metrics"
+    "http://localhost/metrics",
+    "http+unix:///run/user/420/podman/podman.sock:/d/v4.0.0/libpod/pods/json"
   ]
 
   ## HTTP method

plugins/inputs/http/sample.conf.in

@@ -1,8 +1,9 @@
 # Read formatted metrics from one or more HTTP endpoints
 [[inputs.http]]
-  ## One or more URLs from which to read formatted metrics
+  ## One or more URLs from which to read formatted metrics.
   urls = [
-    "http://localhost/metrics"
+    "http://localhost/metrics",
+    "http+unix:///run/user/420/podman/podman.sock:/d/v4.0.0/libpod/pods/json"
   ]
 
   ## HTTP method