Add grafanacloud-specific install script

cmd/agentctl/main.go

@@ -2,13 +2,16 @@
 package main
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"path/filepath"
 	"sort"
+	"time"
 
 	// Adds version information
 	_ "github.com/grafana/agent/pkg/build"
+	"github.com/grafana/agent/pkg/client/grafanacloud"
 	"github.com/olekukonko/tablewriter"
 	"github.com/prometheus/common/version"
 
@@ -35,6 +38,7 @@ func main() {
 		walStatsCmd(),
 		targetStatsCmd(),
 		samplesCmd(),
+		cmdCloudConfig(),
 	)
 
 	_ = cmd.Execute()
@@ -262,6 +266,54 @@ deletion but then comes back at some point).`,
 	}
 }
 
+func cmdCloudConfig() *cobra.Command {
+	var (
+		stackID string
+		apiKey  string
+	)
+
+	cmd := &cobra.Command{
+		Use:   "cloud-config",
+		Short: "Retrieves the cloud config for the Grafana Cloud Agent",
+		Long: `cloud-config connects to Grafana Cloud and retrieves the generated
+config that may be used with this agent.`,
+		Args: cobra.ExactArgs(0),
+
+		// Hidden, this is only expected to be used by scripts.
+		Hidden: true,
+
+		RunE: func(_ *cobra.Command, args []string) error {
+			if stackID == "" {
+				return fmt.Errorf("--stack must be provided")
+			}
+			if apiKey == "" {
+				return fmt.Errorf("--api-key must be provided")
+			}
+
+			cli := grafanacloud.NewClient(nil, apiKey)
+
+			ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+			defer cancel()
+
+			cfg, err := cli.AgentConfig(ctx, stackID)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "could not retrieve agent cloud config: %s\n", err)
+				os.Exit(1)
+			}
+
+			fmt.Println(cfg)
+			return nil
+		},
+	}
+
+	cmd.Flags().StringVarP(&stackID, "stack", "u", "", "stack ID to get a config for")
+	cmd.Flags().StringVarP(&apiKey, "api-key", "p", "", "API key authenticate against Grafana Cloud's API with")
+	must(cmd.MarkFlagRequired("stack"))
+	must(cmd.MarkFlagRequired("api-key"))
+
+	return cmd
+}
+
 func must(err error) {
 	if err != nil {
 		panic(err)

pkg/client/grafanacloud/client.go

@@ -0,0 +1,80 @@
+// Package grafanacloud provides an interface to the Grafana Cloud API.
+package grafanacloud
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"strings"
+
+	"gopkg.in/yaml.v2"
+)
+
+const integrationsApiUrl = "https://integrations-api.grafana.net"
+
+// Client is a grafanacloud API client.
+type Client struct {
+	c      *http.Client
+	apiKey string
+}
+
+// NewClient creates a new Grafana Cloud client. All requests made will be
+// performed using the provided http.Client c. If c is nil, the default
+// http client will be used instead.
+//
+// apiKey will be used to authenticate against the API.
+func NewClient(c *http.Client, apiKey string) *Client {
+	if c == nil {
+		c = http.DefaultClient
+	}
+	return &Client{c: c, apiKey: apiKey}
+}
+
+// AgentConfig generates a Grafana Cloud Agent config from the given stack.
+// The config is returned as a string in YAML form.
+func (c *Client) AgentConfig(ctx context.Context, stackID string) (string, error) {
+	req, err := http.NewRequestWithContext(
+		ctx, "GET",
+		fmt.Sprintf("%s/stacks/%s/agent_config", integrationsApiUrl, stackID),
+		nil,
+	)
+	if err != nil {
+		return "", fmt.Errorf("failed to generate request: %w", err)
+	}
+	req.Header.Add("Authorization", "Bearer "+c.apiKey)
+
+	resp, err := c.c.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("failed to make request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return "", fmt.Errorf("unexpected status code %d", resp.StatusCode)
+	}
+
+	// Even though the API returns json, we'll parse it as YAML here so we can
+	// re-encode it with the same order it was decoded in.
+	payload := struct {
+		Status string        `yaml:"status"`
+		Data   yaml.MapSlice `yaml:"data"`
+		Error  string        `yaml:"error"`
+	}{}
+
+	dec := yaml.NewDecoder(resp.Body)
+	if err := dec.Decode(&payload); err != nil {
+		return "", fmt.Errorf("failed to read response: %w", err)
+	}
+
+	if payload.Status != "success" {
+		return "", fmt.Errorf("request was not successful: %s", payload.Error)
+	}
+
+	// Convert the data to YAML
+	var sb strings.Builder
+	if err := yaml.NewEncoder(&sb).Encode(payload.Data); err != nil {
+		return "", fmt.Errorf("failed to generate YAML config: %w", err)
+	}
+
+	return sb.String(), nil
+}

pkg/client/grafanacloud/client_test.go

@@ -0,0 +1,98 @@
+package grafanacloud
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+const (
+	testSecret  = "secret-key"
+	testStackID = "12345"
+)
+
+func TestClient_AgentConfig(t *testing.T) {
+	httpClient := testClient(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "/stacks/"+testStackID+"/agent_config", r.URL.Path)
+		assert.Equal(t, "Bearer "+testSecret, r.Header.Get("Authorization"))
+
+		_, err := w.Write([]byte(`{
+			"status": "success",
+			"data": {
+				"server": {
+					"http_listen_port": 12345
+				},
+				"integrations": {
+					"agent": {
+						"enabled": true
+					}
+				}
+			}
+		}`))
+		assert.NoError(t, err)
+	}))
+
+	cli := NewClient(httpClient, testSecret)
+	cfg, err := cli.AgentConfig(context.Background(), testStackID)
+	require.NoError(t, err)
+	fmt.Println(cfg)
+
+	expect := `
+server:
+  http_listen_port: 12345
+integrations:
+  agent:
+    enabled: true
+`
+
+	require.YAMLEq(t, expect, cfg)
+}
+
+func TestClient_AgentConfig_Error(t *testing.T) {
+	httpClient := testClient(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+	}))
+
+	cli := NewClient(httpClient, testSecret)
+	_, err := cli.AgentConfig(context.Background(), testStackID)
+	require.Error(t, err, "unexpected status code 404")
+}
+
+func TestClient_AgentConfig_ErrorMessage(t *testing.T) {
+	httpClient := testClient(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, err := w.Write([]byte(`{
+			"status": "error",
+			"error": "Something went wrong"
+		}`))
+		assert.NoError(t, err)
+	}))
+
+	cli := NewClient(httpClient, testSecret)
+	_, err := cli.AgentConfig(context.Background(), testStackID)
+	require.Error(t, err, "request was not successful: Something went wrong")
+}
+
+func testClient(t *testing.T, handler http.HandlerFunc) *http.Client {
+	h := httptest.NewTLSServer(handler)
+	t.Cleanup(func() {
+		h.Close()
+	})
+
+	return &http.Client{
+		Transport: &http.Transport{
+			TLSClientConfig: &tls.Config{
+				InsecureSkipVerify: true,
+			},
+			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+				return net.Dial(network, h.Listener.Addr().String())
+			},
+		},
+	}
+}

production/grafanacloud-install.sh

@@ -0,0 +1,111 @@
+#!/usr/bin/env bash
+# grafanacloud-install.sh installs the Grafana Cloud Agent on supported x86_64
+# Linux systems for Grafana Cloud users. Those who aren't users of Grafana Cloud 
+# or need to install the Agent on a different architecture or platform should 
+# try another installation method.
+#
+# grafanacloud-install.sh has a hard dependency on being run on a supported
+# Linux system. Currently only systems that can install deb or rpm packages 
+# are supported. The target system will try to be detected, but if it cannot, 
+# PACKAGE_SYSTEM can be passed as an environment variable with either rpm or 
+# deb.
+set -euo pipefail
+
+log() {
+  echo "$@" >&2 
+}
+
+fatal() {
+  log "$@"
+  exit 1
+}
+
+#
+# REQUIRED environment variables. 
+#
+GCLOUD_STACK_ID=${GCLOUD_STACK_ID:=} # Stack ID where integrations are installed
+GCLOUD_API_KEY=${GCLOUD_API_KEY:=}   # API key to communicate to the integrations API
+
+[ -z "$GCLOUD_STACK_ID" ] && fatal "Required environment variable $$GCLOUD_STACK_ID not set."
+[ -z "$GCLOUD_API_KEY" ]  && fatal "Required environment variable $$GCLOUD_API_KEY not set."
+
+#
+# OPTIONAL environment variables. 
+#
+
+# Package system to install the Agent with. If not empty, MUST be either rpm or
+# deb. If empty, the script will try to detect the host OS and the appropriate
+# package system to use.
+PACKAGE_SYSTEM=${PACKAGE_SYSTEM:=}
+
+# 
+# Global constants.
+#
+RELEASE_VERSION="0.9.0"
+
+RELEASE_URL="https://github.com/grafana/agent/releases/download/v${RELEASE_VERSION}"
+DEB_URL="${RELEASE_URL}/grafana-agent-${RELEASE_VERSION}-1.x86_64.deb"
+RPM_URL="${RELEASE_URL}/grafana-agent-${RELEASE_VERSION}-1.x86_64.rpm"
+
+main() {
+  if [ -z "$PACKAGE_SYSTEM" ]; then 
+    PACKAGE_SYSTEM=$(detect_package_system)
+  fi
+  log "--- Using package system $PACKAGE_SYSTEM. Downloading and installing package"
+
+  case "$PACKAGE_SYSTEM" in
+    deb)
+      install_deb
+      ;;
+    rpm)
+      install_rpm
+      ;;
+    *)
+      fatal "Unsupported PACKAGE_SYSTEM value $PACKAGE_SYSTEM. Must be either rpm or deb".
+      ;;
+  esac
+
+  log '--- Retrieving config and placing in /etc/grafana-agent.yaml'
+  retrieve_config | sudo tee /etc/grafana-agent.yaml
+
+  log '--- Enabling and starting grafana-agent.service'
+  sudo systemctl enable grafana-agent.service
+  sudo systemctl start grafana-agent.service 
+}
+
+# detect_package_system tries to detect the host distribution to determine if
+# deb or rpm should be used for installing the Agent. Prints out either "deb"
+# or "rpm". Calls fatal if the host OS is not supported.
+detect_package_system() {
+  command -v dpkg >/dev/null 2>&1 && { echo "deb"; return; }
+  command -v rpm  >/dev/null 2>&1 && { echo "rpm"; return; }
+
+  case "$(uname)" in
+    Darwin)
+      fatal 'macOS not supported'
+      ;;
+    *)
+      fatal "Unknown unsupported OS: $(uname)"
+      ;;
+  esac
+}
+
+# install_deb downloads and installs the deb package of the Grafana Cloud Agent.
+install_deb() {
+  curl -sL "${DEB_URL}" -o /tmp/grfana-agent.deb
+  sudo dpkg -i /tmp/grafana-agent.deb
+  rm /tmp/grafana-agent.deb
+}
+
+# install_rpm downloads and installs the deb package of the Grafana Cloud Agent.
+install_rpm() {
+  sudo rpm --reinstall "${RPM_URL}"
+}
+
+# retrieve_config downloads the config file for the Agent and prints out its
+# contents to stdout.
+retrieve_config() {
+  grafana-agentctl cloud-config -u "${GCLOUD_STACK_ID}" -p "${GCLOUD_API_KEY}" || fatal 'Failed to retrieve config'
+}
+
+main