feat: use a debug logger for agent

agent/internal/config/config.go

@@ -0,0 +1,52 @@
+package config
+
+import "os"
+
+// Config represents the configuration for the agent.
+type Config struct {
+	Debug        bool
+	Hostname     string
+	TSControlURL string
+	TSAuthKey    string
+	HPControlURL string
+	HPAuthKey    string
+}
+
+const (
+	DebugEnv        = "HEADPLANE_AGENT_DEBUG"
+	HostnameEnv     = "HEADPLANE_AGENT_HOSTNAME"
+	TSControlURLEnv = "HEADPLANE_AGENT_TS_SERVER"
+	TSAuthKeyEnv    = "HEADPLANE_AGENT_TS_AUTHKEY"
+	HPControlURLEnv = "HEADPLANE_AGENT_HP_SERVER"
+	HPAuthKeyEnv    = "HEADPLANE_AGENT_HP_AUTHKEY"
+)
+
+// Load reads the agent configuration from environment variables.
+func Load() (*Config, error) {
+	c := &Config{
+		Debug:        false,
+		Hostname:     os.Getenv(HostnameEnv),
+		TSControlURL: os.Getenv(TSControlURLEnv),
+		TSAuthKey:    os.Getenv(TSAuthKeyEnv),
+		HPControlURL: os.Getenv(HPControlURLEnv),
+		HPAuthKey:    os.Getenv(HPAuthKeyEnv),
+	}
+
+	if os.Getenv(DebugEnv) == "true" {
+		c.Debug = true
+	}
+
+	if err := validateRequired(c); err != nil {
+		return nil, err
+	}
+
+	if err := validateTSReady(c); err != nil {
+		return nil, err
+	}
+
+	if err := validateHPReady(c); err != nil {
+		return nil, err
+	}
+
+	return c, nil
+}

agent/internal/config/preflight.go

@@ -0,0 +1,72 @@
+package config
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+// Checks to make sure all required environment variables are set
+func validateRequired(config *Config) error {
+	if config.Hostname == "" {
+		return fmt.Errorf("%s is required", HostnameEnv)
+	}
+
+	if config.TSControlURL == "" {
+		return fmt.Errorf("%s is required", TSControlURLEnv)
+	}
+
+	if config.HPControlURL == "" {
+		return fmt.Errorf("%s is required", HPControlURLEnv)
+	}
+
+	if config.TSAuthKey == "" {
+		return fmt.Errorf("%s is required", TSAuthKeyEnv)
+	}
+
+	if config.HPAuthKey == "" {
+		return fmt.Errorf("%s is required", HPAuthKeyEnv)
+	}
+
+	return nil
+}
+
+// Pings the Tailscale control server to make sure it's up and running
+func validateTSReady(config *Config) error {
+	testURL := config.TSControlURL
+	if strings.HasSuffix(testURL, "/") {
+		testURL = testURL[:len(testURL)-1]
+	}
+
+	testURL = fmt.Sprintf("%s/health", testURL)
+	resp, err := http.Get(testURL)
+	if err != nil {
+		return fmt.Errorf("Failed to connect to TS control server: %s", err)
+	}
+
+	if resp.StatusCode != 200 {
+		return fmt.Errorf("Failed to connect to TS control server: %s", resp.Status)
+	}
+
+	return nil
+}
+
+// Pings the Headplane server to make sure it's up and running
+func validateHPReady(config *Config) error {
+	testURL := config.HPControlURL
+	if strings.HasSuffix(testURL, "/") {
+		testURL = testURL[:len(testURL)-1]
+	}
+
+	testURL = fmt.Sprintf("%s/healthz", testURL)
+	resp, err := http.Get(testURL)
+	if err != nil {
+		return fmt.Errorf("Failed to connect to HP control server: %s", err)
+	}
+
+	if resp.StatusCode != 200 {
+		return fmt.Errorf("Failed to connect to HP control server: %s", resp.Status)
+	}
+
+	return nil
+}