[CC-7411] Fix environment variable precedence when linking to HCP (#20527)

Fix so that link API values are used over env vars

When a link is created via the API, those values should take precedence over
the values set by environment variables. This change loads all the env vars
initially as part of the config builder rather than on demand.

agent/config/builder.go

@@ -4,6 +4,7 @@
 package config
 
 import (
+	"crypto/tls"
 	"encoding/base64"
 	"encoding/json"
 	"errors"
@@ -2581,11 +2582,37 @@ func validateAutoConfigAuthorizer(rt RuntimeConfig) error {
 }
 
 func (b *builder) cloudConfigVal(v Config) hcpconfig.CloudConfig {
+	// Load the same environment variables expected by hcp-sdk-go
+	envHostname, ok := os.LookupEnv("HCP_API_ADDRESS")
+	if !ok {
+		if legacyEnvHostname, ok := os.LookupEnv("HCP_API_HOST"); ok {
+			// Remove only https scheme prefixes from the deprecated environment
+			// variable for specifying the API host. Mirrors the same behavior as
+			// hcp-sdk-go.
+			if strings.HasPrefix(strings.ToLower(legacyEnvHostname), "https://") {
+				legacyEnvHostname = legacyEnvHostname[8:]
+			}
+			envHostname = legacyEnvHostname
+		}
+	}
+
+	var envTLSConfig *tls.Config
+	if os.Getenv("HCP_AUTH_TLS") == "insecure" ||
+		os.Getenv("HCP_SCADA_TLS") == "insecure" ||
+		os.Getenv("HCP_API_TLS") == "insecure" {
+		envTLSConfig = &tls.Config{InsecureSkipVerify: true}
+	}
+
 	val := hcpconfig.CloudConfig{
 		ResourceID:   os.Getenv("HCP_RESOURCE_ID"),
 		ClientID:     os.Getenv("HCP_CLIENT_ID"),
 		ClientSecret: os.Getenv("HCP_CLIENT_SECRET"),
+		AuthURL:      os.Getenv("HCP_AUTH_URL"),
+		Hostname:     envHostname,
+		ScadaAddress: os.Getenv("HCP_SCADA_ADDRESS"),
+		TLSConfig:    envTLSConfig,
 	}
+
 	// Node id might get overridden in setup.go:142
 	nodeID := stringVal(v.NodeID)
 	val.NodeID = types.NodeID(nodeID)
@@ -2595,20 +2622,29 @@ func (b *builder) cloudConfigVal(v Config) hcpconfig.CloudConfig {
 		return val
 	}
 
-	val.AuthURL = stringVal(v.Cloud.AuthURL)
+	// Load configuration file variables for anything not set by environment variables
-	val.Hostname = stringVal(v.Cloud.Hostname)
+	if val.AuthURL == "" {
-	val.ScadaAddress = stringVal(v.Cloud.ScadaAddress)
+		val.AuthURL = stringVal(v.Cloud.AuthURL)
-
-	if resourceID := stringVal(v.Cloud.ResourceID); resourceID != "" {
-		val.ResourceID = resourceID
 	}
 
-	if clientID := stringVal(v.Cloud.ClientID); clientID != "" {
+	if val.Hostname == "" {
-		val.ClientID = clientID
+		val.Hostname = stringVal(v.Cloud.Hostname)
 	}
 
-	if clientSecret := stringVal(v.Cloud.ClientSecret); clientSecret != "" {
+	if val.ScadaAddress == "" {
-		val.ClientSecret = clientSecret
+		val.ScadaAddress = stringVal(v.Cloud.ScadaAddress)
+	}
+
+	if val.ResourceID == "" {
+		val.ResourceID = stringVal(v.Cloud.ResourceID)
+	}
+
+	if val.ClientID == "" {
+		val.ClientID = stringVal(v.Cloud.ClientID)
+	}
+
+	if val.ClientSecret == "" {
+		val.ClientSecret = stringVal(v.Cloud.ClientSecret)
 	}
 
 	return val

agent/config/builder_test.go

@@ -15,6 +15,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	hcpconfig "github.com/hashicorp/consul/agent/hcp/config"
 	"github.com/hashicorp/consul/types"
 )
 
@@ -707,3 +708,108 @@ func TestBuilder_WarnCloudConfigWithResourceApis(t *testing.T) {
 		}
 	}
 }
+
+func TestBuilder_CloudConfigWithEnvironmentVars(t *testing.T) {
+	tests := map[string]struct {
+		hcl      string
+		env      map[string]string
+		expected hcpconfig.CloudConfig
+	}{
+		"ConfigurationOnly": {
+			hcl: `cloud{ resource_id = "config-resource-id" client_id = "config-client-id"
+			client_secret = "config-client-secret" auth_url = "auth.config.com"
+			hostname = "api.config.com" scada_address = "scada.config.com"}`,
+			expected: hcpconfig.CloudConfig{
+				ResourceID:   "config-resource-id",
+				ClientID:     "config-client-id",
+				ClientSecret: "config-client-secret",
+				AuthURL:      "auth.config.com",
+				Hostname:     "api.config.com",
+				ScadaAddress: "scada.config.com",
+			},
+		},
+		"EnvVarsOnly": {
+			env: map[string]string{
+				"HCP_RESOURCE_ID":   "env-resource-id",
+				"HCP_CLIENT_ID":     "env-client-id",
+				"HCP_CLIENT_SECRET": "env-client-secret",
+				"HCP_AUTH_URL":      "auth.env.com",
+				"HCP_API_ADDRESS":   "api.env.com",
+				"HCP_SCADA_ADDRESS": "scada.env.com",
+			},
+			expected: hcpconfig.CloudConfig{
+				ResourceID:   "env-resource-id",
+				ClientID:     "env-client-id",
+				ClientSecret: "env-client-secret",
+				AuthURL:      "auth.env.com",
+				Hostname:     "api.env.com",
+				ScadaAddress: "scada.env.com",
+			},
+		},
+		"EnvVarsOverrideConfig": {
+			hcl: `cloud{ resource_id = "config-resource-id" client_id = "config-client-id"
+			client_secret = "config-client-secret" auth_url = "auth.config.com"
+			hostname = "api.config.com" scada_address = "scada.config.com"}`,
+			env: map[string]string{
+				"HCP_RESOURCE_ID":   "env-resource-id",
+				"HCP_CLIENT_ID":     "env-client-id",
+				"HCP_CLIENT_SECRET": "env-client-secret",
+				"HCP_AUTH_URL":      "auth.env.com",
+				"HCP_API_ADDRESS":   "api.env.com",
+				"HCP_SCADA_ADDRESS": "scada.env.com",
+			},
+			expected: hcpconfig.CloudConfig{
+				ResourceID:   "env-resource-id",
+				ClientID:     "env-client-id",
+				ClientSecret: "env-client-secret",
+				AuthURL:      "auth.env.com",
+				Hostname:     "api.env.com",
+				ScadaAddress: "scada.env.com",
+			},
+		},
+		"Combination": {
+			hcl: `cloud{ resource_id = "config-resource-id" client_id = "config-client-id"
+				client_secret = "config-client-secret"}`,
+			env: map[string]string{
+				"HCP_AUTH_URL":      "auth.env.com",
+				"HCP_API_ADDRESS":   "api.env.com",
+				"HCP_SCADA_ADDRESS": "scada.env.com",
+			},
+			expected: hcpconfig.CloudConfig{
+				ResourceID:   "config-resource-id",
+				ClientID:     "config-client-id",
+				ClientSecret: "config-client-secret",
+				AuthURL:      "auth.env.com",
+				Hostname:     "api.env.com",
+				ScadaAddress: "scada.env.com",
+			},
+		},
+	}
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			for k, v := range tc.env {
+				t.Setenv(k, v)
+			}
+			devMode := true
+			builderOpts := LoadOpts{
+				DevMode: &devMode,
+				Overrides: []Source{
+					FileSource{
+						Name:   "overrides",
+						Format: "hcl",
+						Data:   tc.hcl,
+					},
+				},
+			}
+			loaded, err := Load(builderOpts)
+			require.NoError(t, err)
+
+			nodeName, err := os.Hostname()
+			require.NoError(t, err)
+			tc.expected.NodeName = nodeName
+
+			actual := loaded.RuntimeConfig.Cloud
+			require.Equal(t, tc.expected, actual)
+		})
+	}
+}

agent/config/runtime_test.go

@@ -2329,7 +2329,6 @@ func TestLoad_IntegrationWithFlags(t *testing.T) {
 		expected: func(rt *RuntimeConfig) {
 			rt.DataDir = dataDir
 			rt.Cloud = hcpconfig.CloudConfig{
-				// ID is only populated from env if not populated from other sources.
 				ResourceID: "env-id",
 				NodeName:   "thehostname",
 				NodeID:     "",
@@ -2371,8 +2370,7 @@ func TestLoad_IntegrationWithFlags(t *testing.T) {
 		expected: func(rt *RuntimeConfig) {
 			rt.DataDir = dataDir
 			rt.Cloud = hcpconfig.CloudConfig{
-				// ID is only populated from env if not populated from other sources.
+				ResourceID: "env-id",
-				ResourceID: "file-id",
 				NodeName:   "thehostname",
 			}
 

agent/hcp/config/config.go

@@ -46,6 +46,8 @@ func (c *CloudConfig) Resource() (resource.Resource, error) {
 	return resource.FromString(c.ResourceID)
 }
 
+// HCPConfig returns a configuration to use with the HCP SDK. It assumes that the environment
+// variables for the HCP configuration have already been loaded and set in the CloudConfig.
 func (c *CloudConfig) HCPConfig(opts ...hcpcfg.HCPConfigOption) (hcpcfg.HCPConfig, error) {
 	if c.TLSConfig == nil {
 		c.TLSConfig = &tls.Config{}
@@ -62,7 +64,7 @@ func (c *CloudConfig) HCPConfig(opts ...hcpcfg.HCPConfigOption) (hcpcfg.HCPConfi
 	if c.ScadaAddress != "" {
 		opts = append(opts, hcpcfg.WithSCADA(c.ScadaAddress, c.TLSConfig))
 	}
-	opts = append(opts, hcpcfg.FromEnv(), hcpcfg.WithoutBrowserLogin())
+	opts = append(opts, hcpcfg.WithoutBrowserLogin())
 	return hcpcfg.NewHCPConfig(opts...)
 }