Extend client APIs for support of existing stacks in more cases (#2338)

Move some methods from the serverless provider to the clients, so they can be
more easily reused, and add some additional methods that can be useful to
extend the support of existing stacks.

Co-authored-by: Mario Rodriguez Molins <marrodmo@gmail.com>

Author: jsoriano

internal/elasticsearch/client.go

@@ -189,6 +189,37 @@ func (client *Client) CheckHealth(ctx context.Context) error {
 	return nil
 }
 
+type Info struct {
+	Name        string `json:"name"`
+	ClusterName string `json:"cluster_name"`
+	ClusterUUID string `json:"cluster_uuid"`
+	Version     struct {
+		Number      string `json:"number"`
+		BuildFlavor string `json:"build_flavor"`
+	} `json:"version`
+}
+
+// Info gets cluster information and metadata.
+func (client *Client) Info(ctx context.Context) (*Info, error) {
+	resp, err := client.Client.Info(client.Client.Info.WithContext(ctx))
+	if err != nil {
+		return nil, fmt.Errorf("error getting cluster info: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("failed to get cluster info: %s", resp.String())
+	}
+
+	var info Info
+	err = json.NewDecoder(resp.Body).Decode(&info)
+	if err != nil {
+		return nil, fmt.Errorf("error decoding cluster info: %w", err)
+	}
+
+	return &info, nil
+}
+
 // IsFailureStoreAvailable checks if the failure store is available.
 func (client *Client) IsFailureStoreAvailable(ctx context.Context) (bool, error) {
 	// FIXME: Using the low-level transport till the API SDK supports the failure store.

internal/elasticsearch/client_test.go

@@ -93,6 +93,13 @@ func TestClusterHealth(t *testing.T) {
 	}
 }
 
+func TestClusterInfo(t *testing.T) {
+	client := test.NewClient(t, "./testdata/elasticsearch-9-info")
+	info, err := client.Info(context.Background())
+	require.NoError(t, err)
+	assert.Equal(t, "9.0.0-SNAPSHOT", info.Version.Number)
+}
+
 func writeCACertFile(t *testing.T, cert *x509.Certificate) string {
 	var d bytes.Buffer
 	err := pem.Encode(&d, &pem.Block{

internal/elasticsearch/testdata/elasticsearch-9-info.yaml

@@ -0,0 +1,119 @@
+---
+version: 2
+interactions:
+    - id: 0
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 0
+        transfer_encoding: []
+        trailer: {}
+        host: ""
+        remote_addr: ""
+        request_uri: ""
+        body: ""
+        form: {}
+        headers:
+            Authorization:
+                - Basic ZWxhc3RpYzpjaGFuZ2VtZQ==
+            User-Agent:
+                - go-elasticsearch/7.17.10 (linux amd64; Go 1.23.4)
+            X-Elastic-Client-Meta:
+                - es=7.17.10,go=1.23.4,t=7.17.10,hc=1.23.4
+        url: https://127.0.0.1:9200/
+        method: GET
+      response:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        transfer_encoding: []
+        trailer: {}
+        content_length: 547
+        uncompressed: false
+        body: |
+            {
+              "name" : "da1c4d2b1379",
+              "cluster_name" : "elasticsearch",
+              "cluster_uuid" : "KPcvXrW1Rnega2GT0sn3mg",
+              "version" : {
+                "number" : "9.0.0-SNAPSHOT",
+                "build_flavor" : "default",
+                "build_type" : "docker",
+                "build_hash" : "873dc52360a9265824a70b3113c3dd350ff9249a",
+                "build_date" : "2025-01-13T13:20:37.908330789Z",
+                "build_snapshot" : true,
+                "lucene_version" : "10.0.0",
+                "minimum_wire_compatibility_version" : "8.18.0",
+                "minimum_index_compatibility_version" : "8.0.0"
+              },
+              "tagline" : "You Know, for Search"
+            }
+        headers:
+            Content-Length:
+                - "547"
+            Content-Type:
+                - application/json
+            X-Elastic-Product:
+                - Elasticsearch
+        status: 200 OK
+        code: 200
+        duration: 3.494911ms
+    - id: 1
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 0
+        transfer_encoding: []
+        trailer: {}
+        host: ""
+        remote_addr: ""
+        request_uri: ""
+        body: ""
+        form: {}
+        headers:
+            Authorization:
+                - Basic ZWxhc3RpYzpjaGFuZ2VtZQ==
+            User-Agent:
+                - go-elasticsearch/7.17.10 (linux amd64; Go 1.23.4)
+            X-Elastic-Client-Meta:
+                - es=7.17.10,go=1.23.4,t=7.17.10,hc=1.23.4
+        url: https://127.0.0.1:9200/
+        method: GET
+      response:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        transfer_encoding: []
+        trailer: {}
+        content_length: 547
+        uncompressed: false
+        body: |
+            {
+              "name" : "da1c4d2b1379",
+              "cluster_name" : "elasticsearch",
+              "cluster_uuid" : "KPcvXrW1Rnega2GT0sn3mg",
+              "version" : {
+                "number" : "9.0.0-SNAPSHOT",
+                "build_flavor" : "default",
+                "build_type" : "docker",
+                "build_hash" : "873dc52360a9265824a70b3113c3dd350ff9249a",
+                "build_date" : "2025-01-13T13:20:37.908330789Z",
+                "build_snapshot" : true,
+                "lucene_version" : "10.0.0",
+                "minimum_wire_compatibility_version" : "8.18.0",
+                "minimum_index_compatibility_version" : "8.0.0"
+              },
+              "tagline" : "You Know, for Search"
+            }
+        headers:
+            Content-Length:
+                - "547"
+            Content-Type:
+                - application/json
+            X-Elastic-Product:
+                - Elasticsearch
+        status: 200 OK
+        code: 200
+        duration: 474.3µs

internal/fleetserver/client.go

@@ -0,0 +1,128 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package fleetserver
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+
+	"github.com/elastic/elastic-package/internal/certs"
+	"github.com/elastic/elastic-package/internal/logger"
+)
+
+// Client is a client for Fleet Server API. This API only supports authentication with API
+// keys, though some endpoints are also available without any authentication.
+type Client struct {
+	address string
+	apiKey  string
+
+	certificateAuthority string
+	tlSkipVerify         bool
+
+	http            *http.Client
+	httpClientSetup func(*http.Client) *http.Client
+}
+
+type ClientOption func(*Client)
+
+func NewClient(address string, opts ...ClientOption) (*Client, error) {
+	client := Client{
+		address: address,
+	}
+
+	for _, opt := range opts {
+		opt(&client)
+	}
+
+	httpClient, err := client.httpClient()
+	if err != nil {
+		return nil, fmt.Errorf("cannot create HTTP client: %w", err)
+	}
+	client.http = httpClient
+	return &client, nil
+}
+
+// APIKey option sets the API key to be used by the client for authentication.
+func APIKey(apiKey string) ClientOption {
+	return func(c *Client) {
+		c.apiKey = apiKey
+	}
+}
+
+// TLSSkipVerify option disables TLS verification.
+func TLSSkipVerify() ClientOption {
+	return func(c *Client) {
+		c.tlSkipVerify = true
+	}
+}
+
+// CertificateAuthority sets the certificate authority to be used by the client.
+func CertificateAuthority(certificateAuthority string) ClientOption {
+	return func(c *Client) {
+		c.certificateAuthority = certificateAuthority
+	}
+}
+
+// HTTPClientSetup adds an initializing function for the http client.
+func HTTPClientSetup(setup func(*http.Client) *http.Client) ClientOption {
+	return func(c *Client) {
+		c.httpClientSetup = setup
+	}
+}
+
+func (c *Client) httpClient() (*http.Client, error) {
+	client := &http.Client{}
+	if c.tlSkipVerify {
+		client.Transport = &http.Transport{
+			TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+		}
+	} else if c.certificateAuthority != "" {
+		rootCAs, err := certs.SystemPoolWithCACertificate(c.certificateAuthority)
+		if err != nil {
+			return nil, fmt.Errorf("reading CA certificate: %w", err)
+		}
+		client.Transport = &http.Transport{
+			TLSClientConfig: &tls.Config{RootCAs: rootCAs},
+		}
+	}
+
+	if c.httpClientSetup != nil {
+		client = c.httpClientSetup(client)
+	}
+
+	return client, nil
+}
+
+func (c *Client) httpRequest(ctx context.Context, method, resourcePath string, reqBody io.Reader) (*http.Request, error) {
+	base, err := url.Parse(c.address)
+	if err != nil {
+		return nil, fmt.Errorf("could not create base URL from host: %v: %w", c.address, err)
+	}
+
+	rel, err := url.Parse(resourcePath)
+	if err != nil {
+		return nil, fmt.Errorf("could not create relative URL from resource path: %v: %w", resourcePath, err)
+	}
+
+	u := base.JoinPath(rel.EscapedPath())
+	u.RawQuery = rel.RawQuery
+
+	logger.Debugf("%s %s", method, u)
+
+	req, err := http.NewRequestWithContext(ctx, method, u.String(), reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("could not create %v request to Fleet Server API resource: %s: %w", method, resourcePath, err)
+	}
+
+	if c.apiKey != "" {
+		req.Header.Set("Authorization", "ApiKey "+c.apiKey)
+	}
+
+	return req, nil
+}

internal/fleetserver/status.go

@@ -0,0 +1,56 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package fleetserver
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/url"
+
+	"github.com/elastic/elastic-package/internal/logger"
+)
+
+type Status struct {
+	Name   string `json:"name"`
+	Status string `json:"status"`
+
+	// Version is only present if client is authenticated.
+	Version struct {
+		Number string `json:"number"`
+	} `json:"version"`
+}
+
+func (c *Client) Status(ctx context.Context) (*Status, error) {
+	statusURL, err := url.JoinPath(c.address, "/api/status")
+	if err != nil {
+		return nil, fmt.Errorf("could not build URL: %w", err)
+	}
+	logger.Debugf("GET %s", statusURL)
+	req, err := c.httpRequest(ctx, "GET", statusURL, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("request failed (url: %s): %w", statusURL, err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode >= 300 {
+		return nil, fmt.Errorf("unexpected status code %v", resp.StatusCode)
+	}
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response body: %w", err)
+	}
+	var status Status
+	err = json.Unmarshal(body, &status)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse response body: %w", err)
+	}
+
+	return &status, nil
+}