amtool to support http_config to access alertmanager (#2764)

* Support http_config for amtool

Co-authored-by: Julien Pivotto <roidelapluie@gmail.com>
Co-authored-by: Simon Pasquier <spasquie@redhat.com>
Signed-off-by: clyang82 <chuyang@redhat.com>

cli/config/http_config.go

@@ -0,0 +1,39 @@
+// Copyright 2021 Prometheus Team
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+import (
+	"io/ioutil"
+	"path/filepath"
+
+	promconfig "github.com/prometheus/common/config"
+	"gopkg.in/yaml.v2"
+)
+
+// LoadHTTPConfigFile returns HTTPClientConfig for the given http_config file
+func LoadHTTPConfigFile(filename string) (*promconfig.HTTPClientConfig, error) {
+	b, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	httpConfig := &promconfig.HTTPClientConfig{}
+	err = yaml.UnmarshalStrict(b, httpConfig)
+	if err != nil {
+		return nil, err
+	}
+	httpConfig.SetDirectory(filepath.Dir(filepath.Dir(filename)))
+
+	return httpConfig, nil
+}

cli/config/http_config_test.go

@@ -0,0 +1,55 @@
+// Copyright 2021 Prometheus Team
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestInvalidHTTPConfig(t *testing.T) {
+	_, err := LoadHTTPConfigFile("testdata/http_config.bad.yml")
+	errMsg := `authorization type cannot be set to "basic", use "basic_auth" instead`
+	if !strings.Contains(err.Error(), errMsg) {
+		t.Errorf("Expected error for invalid HTTP client configuration to contain %q but got: %s", errMsg, err)
+	}
+}
+
+func TestValidHTTPConfig(t *testing.T) {
+	cfg, err := LoadHTTPConfigFile("testdata/http_config.good.yml")
+	if err != nil {
+		t.Fatalf("Error loading HTTP client config: %v", err)
+	}
+
+	proxyURL := "http://remote.host"
+	if cfg.ProxyURL.String() != proxyURL {
+		t.Fatalf("Expected proxy_url is %q but got: %s", proxyURL, cfg.ProxyURL.String())
+	}
+}
+
+func TestValidBasicAuthHTTPConfig(t *testing.T) {
+	cfg, err := LoadHTTPConfigFile("testdata/http_config.basic_auth.good.yml")
+	if err != nil {
+		t.Fatalf("Error loading HTTP client config: %v", err)
+	}
+
+	if cfg.BasicAuth.Username != "user" {
+		t.Fatalf("Expected username is %q but got: %s", "user", cfg.BasicAuth.Username)
+	}
+
+	password := string(cfg.BasicAuth.Password)
+	if password != "password" {
+		t.Fatalf("Expected password is %q but got: %s", "password", password)
+	}
+}

cli/config/testdata/http_config.bad.yml

@@ -0,0 +1,2 @@
+authorization:
+  type: Basic

cli/config/testdata/http_config.basic_auth.good.yml

@@ -0,0 +1,3 @@
+basic_auth:
+  username: user
+  password: password

cli/config/testdata/http_config.good.yml

@@ -0,0 +1,4 @@
+authorization:
+  type: Bearer
+  credentials: theanswertothegreatquestionoflifetheuniverseandeverythingisfortytwo
+proxy_url: "http://remote.host"

cli/root.go

@@ -14,9 +14,7 @@
 package cli
 
 import (
-	"crypto/tls"
 	"fmt"
-	"net/http"
 	"net/url"
 	"os"
 	"path"
@@ -40,7 +38,7 @@ var (
 	alertmanagerURL *url.URL
 	output          string
 	timeout         time.Duration
-	tlsConfig       *tls.Config
+	httpConfigFile  string
 	versionCheck    bool
 
 	configFiles = []string{os.ExpandEnv("$HOME/.config/amtool/config.yml"), "/etc/amtool/config.yml"}
@@ -85,8 +83,8 @@ func NewAlertmanagerClient(amURL *url.URL) *client.Alertmanager {
 
 	cr := clientruntime.New(address, path.Join(amURL.Path, defaultAmApiv2path), schemes)
 
-	cr.Transport = &http.Transport{
-		TLSClientConfig: tlsConfig,
+	if amURL.User != nil && httpConfigFile != "" {
+		kingpin.Fatalf("basic authentication and http.config.file are mutually exclusive")
 	}
 
 	if amURL.User != nil {
@@ -94,6 +92,20 @@ func NewAlertmanagerClient(amURL *url.URL) *client.Alertmanager {
 		cr.DefaultAuthentication = clientruntime.BasicAuth(amURL.User.Username(), password)
 	}
 
+	if httpConfigFile != "" {
+		var err error
+		httpConfig, err := config.LoadHTTPConfigFile(httpConfigFile)
+		if err != nil {
+			kingpin.Fatalf("failed to load HTTP config file: %v", err)
+		}
+
+		httpclient, err := promconfig.NewClientFromConfig(*httpConfig, "amtool")
+		if err != nil {
+			kingpin.Fatalf("failed to create a new HTTP client: %v", err)
+		}
+		cr = clientruntime.NewWithClient(address, path.Join(amURL.Path, defaultAmApiv2path), schemes, httpclient)
+	}
+
 	c := client.New(cr, strfmt.Default)
 
 	if !versionCheck {
@@ -117,7 +129,6 @@ func NewAlertmanagerClient(amURL *url.URL) *client.Alertmanager {
 func Execute() {
 	var (
 		app = kingpin.New("amtool", helpRoot).UsageWriter(os.Stdout)
-		tls = promconfig.TLSConfig{}
 	)
 
 	format.InitFormatFlags(app)
@@ -126,20 +137,12 @@ func Execute() {
 	app.Flag("alertmanager.url", "Alertmanager to talk to").URLVar(&alertmanagerURL)
 	app.Flag("output", "Output formatter (simple, extended, json)").Short('o').Default("simple").EnumVar(&output, "simple", "extended", "json")
 	app.Flag("timeout", "Timeout for the executed command").Default("30s").DurationVar(&timeout)
-	app.Flag("tls.certfile", "TLS client certificate file").PlaceHolder("<filename>").ExistingFileVar(&tls.CertFile)
-	app.Flag("tls.keyfile", "TLS client private key file").PlaceHolder("<filename>").ExistingFileVar(&tls.KeyFile)
-	app.Flag("tls.cafile", "TLS trusted certificate authorities file").PlaceHolder("<filename>").ExistingFileVar(&tls.CAFile)
-	app.Flag("tls.servername", "ServerName to verify hostname of alertmanager").PlaceHolder("<string>").StringVar(&tls.ServerName)
-	app.Flag("tls.insecure.skip.verify", "Skip TLS certificate verification").Default("false").BoolVar(&tls.InsecureSkipVerify)
+	app.Flag("http.config.file", "HTTP client configuration file for amtool to connect to Alertmanager.").PlaceHolder("<filename>").ExistingFileVar(&httpConfigFile)
 	app.Flag("version-check", "Check alertmanager version. Use --no-version-check to disable.").Default("true").BoolVar(&versionCheck)
 
 	app.Version(version.Print("amtool"))
 	app.GetFlag("help").Short('h')
 	app.UsageTemplate(kingpin.CompactUsageTemplate)
-	app.PreAction(func(pc *kingpin.ParseContext) (err error) {
-		tlsConfig, err = promconfig.NewTLSConfig(&tls)
-		return err
-	})
 
 	resolver, err := config.NewResolver(configFiles, legacyFlags)
 	if err != nil {
@@ -191,22 +194,8 @@ static configuration:
 	date.format
 		Sets the output format for dates. Defaults to "2006-01-02 15:04:05 MST"
 
-	tls.certfile
-		TLS client certificate file for mutual-TLS authentication.
-		Requires tls.keyfile to be useful.
-
-	tls.keyfile
-		TLS client private key file for mutual-TLS authentication.
-		Requires tls.certfile to be useful.
-
-	tls.cafile
-		TLS trusted certificate authorities file.
-
-	tls.servername
-		ServerName to verify hostname of alertmanager.
-
-	tls.insecure.skip.verify
-		Skips TLS certificate verification for all HTTPS requests.
-		Defaults to false.
+	http.config.file
+		HTTP client configuration file for amtool to connect to Alertmanager.
+		The format is https://prometheus.io/docs/alerting/latest/configuration/#http_config.
 `
 )