Mapping SAML attributes to Genesys Cloud SCIM user profiles with Go

How-To-Articles
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Mapping SAML attributes to Genesys Cloud SCIM user profiles with Go

What You Will Build

  • A Go service that ingests a SAML assertion XML payload, extracts custom <Attribute> elements, validates them against a defined schema, and pushes the values to Genesys Cloud user extension attributes via SCIM.
  • This implementation uses the Genesys Cloud SCIM API (/api/v2/scim/v2/Users/{userId}) and the platformclientv2 Go SDK.
  • The code is written in Go 1.21+ and relies on the standard library for XML parsing, JSON serialization, and structured logging.

Prerequisites

  • OAuth 2.0 client credentials flow configured in Genesys Cloud with the scim:users:readwrite scope.
  • github.com/mypurecloud/platform-client-go/platformclientv2 v1.20.0 or later.
  • Go runtime version 1.21 or higher.
  • No external XML or HTTP libraries required; the standard library provides all necessary components.

Authentication Setup

Genesys Cloud server-to-server integrations require the OAuth 2.0 client credentials grant. The following function establishes the initial token and implements a refresh mechanism. The platformclientv2 SDK handles automatic token renewal when configured correctly, but explicit control ensures predictable retry behavior during 429 rate limits.

package main

import (
	"context"
	"fmt"
	"net/http"
	"time"

	"github.com/mypurecloud/platform-client-go/platformclientv2"
)

type GenesysClient struct {
	Platform *platformclientv2.ApiClient
	Token    *platformclientv2.OAuthResponse
}

func NewGenesysClient(env, clientId, clientSecret string) (*GenesysClient, error) {
	config, err := platformclientv2.GetDefaultConfiguration()
	if err != nil {
		return nil, fmt.Errorf("failed to initialize platform client configuration: %w", err)
	}

	// Set environment-specific base URL
	config.BasePath = fmt.Sprintf("https://%s.mygen.com", env)
	config.HTTPClient = &http.Client{Timeout: 30 * time.Second}

	apiClient := platformclientv2.NewApiClient(config)

	// Initialize OAuth client
	oauthApi := platformclientv2.NewOAuthApi(apiClient)
	token, _, err := oauthApi.PostOauthToken(
		"client_credentials",
		"scim:users:readwrite",
		nil,
	).Execute()
	if err != nil {
		return nil, fmt.Errorf("oauth token acquisition failed: %w", err)
	}

	// Attach token to API client for automatic authorization header injection
	apiClient.SetAccessToken(token.AccessToken)
	apiClient.SetTokenType(token.TokenType)

	return &GenesysClient{
		Platform: apiClient,
		Token:    token,
	}, nil
}

The scim:users:readwrite scope grants permission to query existing user attributes and apply PATCH operations. The SDK caches the token and automatically appends the Authorization: Bearer <token> header to subsequent requests.

Implementation

Step 1: Parse SAML assertion and extract custom attributes

SAML assertions are XML documents containing an <AttributeStatement> block. Each <Attribute> element carries a Name and one or more <AttributeValue> children. The parser extracts these into a map for downstream validation.

package main

import (
	"encoding/xml"
	"fmt"
)

type SAMLAttribute struct {
	XMLName  xml.Name `xml:"Attribute"`
	Name     string   `xml:"Name,attr"`
	Values   []string `xml:"AttributeValue"`
}

type SAMLAssertion struct {
	XMLName xml.Name `xml:"Assertion"`
	AttributeStatement struct {
		Attributes []SAMLAttribute `xml:"AttributeStatement>Attribute"`
	} `xml:"AttributeStatement"`
}

func ParseSAMLAssertion(xmlData []byte) (map[string][]string, error) {
	var assertion SAMLAssertion
	err := xml.Unmarshal(xmlData, &assertion)
	if err != nil {
		return nil, fmt.Errorf("saml xml unmarshal failed: %w", err)
	}

	extracted := make(map[string][]string)
	for _, attr := range assertion.AttributeStatement.Attributes {
		if len(attr.Values) == 0 {
			continue
		}
		extracted[attr.Name] = attr.Values
	}
	return extracted, nil
}

The XML parser ignores empty attributes and returns a clean map. This approach avoids XPath dependencies and keeps the binary footprint minimal.

Step 2: Validate attributes against a schema definition

Genesys Cloud extension attributes have strict type requirements. The mapping service enforces a schema that declares expected attribute names, data types, and multi-value support. Invalid attributes are rejected before reaching the API.

package main

import (
	"fmt"
	"strings"
)

type AttributeSchema struct {
	Name        string
	AllowedType string // "string" or "int"
	IsMultiVal  bool
}

var schemaDefinition = map[string]AttributeSchema{
	"custom_department": {Name: "custom_department", AllowedType: "string", IsMultiVal: false},
	"custom_cost_center": {Name: "custom_cost_center", AllowedType: "int", IsMultiVal: false},
	"custom_roles": {Name: "custom_roles", AllowedType: "string", IsMultiVal: true},
}

func ValidateAttributes(raw map[string][]string) (map[string][]string, []string, error) {
	valid := make(map[string][]string)
	failed := []string{}

	for name, values := range raw {
		schema, exists := schemaDefinition[name]
		if !exists {
			failed = append(failed, fmt.Sprintf("unknown attribute: %s", name))
			continue
		}

		if !schema.IsMultiVal && len(values) > 1 {
			failed = append(failed, fmt.Sprintf("single-value attribute %s received %d values", name, len(values)))
			continue
		}

		if schema.AllowedType == "int" {
			for _, v := range values {
				if _, err := fmt.Sscanf(v, "%d", new(int)); err != nil {
					failed = append(failed, fmt.Sprintf("attribute %s expected int, got: %s", name, v))
					continue
				}
			}
		}

		valid[name] = values
	}

	return valid, failed, nil
}

The validation step catches type mismatches and schema violations early. This prevents unnecessary API calls and reduces 400 Bad Request responses from Genesys Cloud.

Step 3: Handle length limits and resolve multi-valued conflicts

Genesys Cloud extension attributes enforce a 500-character limit for string values. The handler truncates values that exceed 250 characters and falls back to a SHA256 hash when they exceed 400 characters. Multi-valued attributes require a merge strategy to prevent accidental data loss.

package main

import (
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"strings"
)

const (
	MaxStringLen = 500
	TruncateThreshold = 250
	HashThreshold = 400
)

func ProcessAttributeValue(value string) string {
	if len(value) <= TruncateThreshold {
		return value
	}
	if len(value) <= HashThreshold {
		// Truncate and append indicator
		return value[:TruncateThreshold] + "..."
	}
	// Hash long strings to preserve uniqueness within limits
	hash := sha256.Sum256([]byte(value))
	return "HASH:" + hex.EncodeToString(hash[:])[:36]
}

func MergeMultiValued(existing []string, incoming []string) []string {
	seen := make(map[string]bool)
	merged := []string{}

	for _, v := range existing {
		if !seen[v] {
			seen[v] = true
			merged = append(merged, v)
		}
	}

	for _, v := range incoming {
		processed := ProcessAttributeValue(v)
		if !seen[processed] {
			seen[processed] = true
			merged = append(merged, processed)
		}
	}

	return merged
}

The truncation logic preserves data integrity while respecting platform limits. The merge function deduplicates values and applies length processing to incoming data before combining it with existing values.

Step 4: Construct and send SCIM PATCH requests

Genesys Cloud SCIM endpoints use RFC 6902 JSON Patch. The handler fetches the current user profile, calculates the delta, and issues a PATCH request. The SDK abstracts the HTTP layer, but the underlying request follows standard SCIM conventions.

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"time"

	"github.com/mypurecloud/platform-client-go/platformclientv2"
)

type JSONPatchOp struct {
	Op    string `json:"op"`
	Path  string `json:"path"`
	Value any    `json:"value,omitempty"`
}

func UpdateSCIMUser(client *GenesysClient, userId string, attributes map[string][]string) error {
	// Fetch existing user to resolve multi-valued conflicts
	userApi := platformclientv2.NewUsersApi(client.Platform)
	user, resp, err := userApi.GetScimV2User(context.Background(), userId, false, false, nil, nil)
	if err != nil {
		if resp.StatusCode == http.StatusUnauthorized || resp.StatusCode == http.StatusForbidden {
			return fmt.Errorf("scim authorization failed (status %d): %w", resp.StatusCode, err)
		}
		if resp.StatusCode == http.StatusTooManyRequests {
			return fmt.Errorf("rate limit exceeded, retry after %s: %w", resp.Header.Get("Retry-After"), err)
		}
		return fmt.Errorf("failed to fetch user %s: %w", userId, err)
	}

	patchOps := []JSONPatchOp{}

	for name, values := range attributes {
		// Map custom attribute name to Genesys extension attribute path
		extName := fmt.Sprintf("attr_%s", strings.ReplaceAll(strings.ToLower(name), " ", "_"))
		path := fmt.Sprintf("/urn:ietf:params:scim:schemas:extension:genesys:2.0:User/extensionAttributes/%s", extName)

		var targetValue any
		if schema, exists := schemaDefinition[name]; exists && schema.IsMultiVal {
			// Extract existing values from user profile
			existing := []string{}
			if user.ExtensionAttributes != nil {
				if val, ok := user.ExtensionAttributes[extName]; ok {
					if arr, ok := val.([]interface{}); ok {
						for _, v := range arr {
							existing = append(existing, fmt.Sprintf("%v", v))
						}
					}
				}
			}
			merged := MergeMultiValued(existing, values)
			targetValue = merged
		} else {
			processed := ProcessAttributeValue(values[0])
			targetValue = processed
		}

		patchOps = append(patchOps, JSONPatchOp{
			Op:    "replace",
			Path:  path,
			Value: targetValue,
		})
	}

	if len(patchOps) == 0 {
		return nil
	}

	// Serialize patch body
	body, err := json.Marshal(map[string]any{
		"ops": patchOps,
	})
	if err != nil {
		return fmt.Errorf("json marshal failed: %w", err)
	}

	// Execute PATCH via SDK
	_, resp, err = userApi.PatchScimV2User(context.Background(), userId, string(body), nil)
	if err != nil {
		if resp.StatusCode == http.StatusTooManyRequests {
			// Implement exponential backoff in production
			time.Sleep(2 * time.Second)
			_, _, err = userApi.PatchScimV2User(context.Background(), userId, string(body), nil)
			if err != nil {
				return fmt.Errorf("scim patch retry failed: %w", err)
			}
		}
		return fmt.Errorf("scim patch failed (status %d): %w", resp.StatusCode, err)
	}

	return nil
}

The SDK call PatchScimV2User translates to a PATCH request against /api/v2/scim/v2/Users/{userId}. The request body follows RFC 6902 strictly. Genesys Cloud returns 204 No Content on success.

HTTP Request/Response Cycle Reference:

PATCH /api/v2/scim/v2/Users/a1b2c3d4-e5f6-7890-abcd-ef1234567890 HTTP/1.1
Host: usw2.mygen.com
Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...
Content-Type: application/json
Accept: application/json

{
  "ops": [
    {
      "op": "replace",
      "path": "/urn:ietf:params:scim:schemas:extension:genesys:2.0:User/extensionAttributes/attr_custom_department",
      "value": "Engineering"
    },
    {
      "op": "replace",
      "path": "/urn:ietf:params:scim:schemas:extension:genesys:2.0:User/extensionAttributes/attr_custom_roles",
      "value": ["admin", "agent", "supervisor"]
    }
  ]
}

HTTP/1.1 204 No Content
X-Request-Id: req_8f7e6d5c4b3a2910
X-Response-Time: 124ms

Step 5: Structured logging for mapping failures

IdP configuration debugging requires precise failure traces. The handler uses Go 1.21 slog to emit structured logs that capture attribute names, validation errors, and HTTP status codes without leaking sensitive PII.

package main

import (
	"log/slog"
	"os"
)

var logger = slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
	Level: slog.LevelInfo,
}))

func LogMappingFailure(userId string, failedAttrs []string, err error) {
	logger.Error("saml_to_scim_mapping_failed",
		slog.String("userId", userId),
		slog.Any("failed_attributes", failedAttrs),
		slog.String("reason", err.Error()),
		slog.Time("timestamp", time.Now()),
	)
}

The logger outputs JSON lines that integrate directly with Elasticsearch, Datadog, or Genesys Cloud Observability. Each failure record includes the exact attributes that triggered validation or transformation rules.

Complete Working Example

The following script combines all components into a single executable module. Replace the placeholder credentials and SAML payload before execution.

package main

import (
	"context"
	"fmt"
	"log/slog"
	"os"
	"time"

	"github.com/mypurecloud/platform-client-go/platformclientv2"
)

func main() {
	logger = slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelInfo}))

	// 1. Initialize Genesys Cloud client
	client, err := NewGenesysClient("usw2", "YOUR_CLIENT_ID", "YOUR_CLIENT_SECRET")
	if err != nil {
		logger.Error("initialization_failed", slog.String("error", err.Error()))
		os.Exit(1)
	}

	// 2. Simulate incoming SAML assertion XML
	samlPayload := []byte(`<?xml version="1.0"?>
	<saml2:Assertion xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion" ID="assertion_123" IssueInstant="2024-01-15T10:00:00Z" Version="2.0">
		<saml2:AttributeStatement>
			<saml2:Attribute Name="custom_department">
				<saml2:AttributeValue>Global Engineering Division</saml2:AttributeValue>
			</saml2:Attribute>
			<saml2:Attribute Name="custom_roles">
				<saml2:AttributeValue>agent</saml2:AttributeValue>
				<saml2:AttributeValue>supervisor</saml2:AttributeValue>
			</saml2:Attribute>
			<saml2:Attribute Name="custom_cost_center">
				<saml2:AttributeValue>4582</saml2:AttributeValue>
			</saml2:Attribute>
		</saml2:AttributeStatement>
	</saml2:Assertion>`)

	// 3. Parse and validate
	extracted, err := ParseSAMLAssertion(samlPayload)
	if err != nil {
		logger.Error("saml_parse_error", slog.String("error", err.Error()))
		os.Exit(1)
	}

	valid, failed, err := ValidateAttributes(extracted)
	if len(failed) > 0 {
		LogMappingFailure("unknown", failed, fmt.Errorf("validation rejected attributes"))
	}

	// 4. Push to SCIM
	userId := "a1b2c3d4-e5f6-7890-abcd-ef1234567890"
	err = UpdateSCIMUser(client, userId, valid)
	if err != nil {
		LogMappingFailure(userId, nil, err)
		os.Exit(1)
	}

	logger.Info("scim_update_complete", slog.String("userId", userId), slog.Int("attributes_processed", len(valid)))
}

The script initializes the platform client, parses a static SAML payload, validates against the schema, applies length/merge logic, and executes the SCIM PATCH. Error paths terminate with structured logs.

Common Errors & Debugging

Error: 401 Unauthorized or 403 Forbidden

  • Cause: The OAuth client lacks the scim:users:readwrite scope, or the token expired.
  • Fix: Verify the client credentials in the Genesys Cloud admin console under Integrations. Regenerate the token and ensure the Authorization header matches the Bearer format.
  • Code adjustment: The NewGenesysClient function returns the exact HTTP status code. Wrap the token acquisition in a retry loop if the IdP token endpoint is throttling.

Error: 429 Too Many Requests

  • Cause: The SCIM endpoint enforces per-tenant rate limits. Bulk SAML events trigger cascading retries.
  • Fix: Implement exponential backoff with jitter. The UpdateSCIMUser function demonstrates a single retry. Production systems should use a worker pool with token buckets.
  • Code adjustment: Read the Retry-After header and sleep accordingly before reissuing the PATCH.

Error: 400 Bad Request (SCIM Schema Mismatch)

  • Cause: The path in the JSON Patch operation does not match an existing extension attribute in Genesys Cloud, or the value type violates the schema.
  • Fix: Confirm the extension attribute exists in Genesys Cloud under People > Profiles > Extension Attributes. Ensure the attr_ prefix matches exactly.
  • Code adjustment: Validate the extName construction against a pre-synced attribute registry before building the patch array.

Error: XML Unmarshal Panic or Empty Map

  • Cause: The SAML assertion uses a different namespace prefix or contains encrypted attributes.
  • Fix: Standardize the IdP output to use urn:oasis:names:tc:SAML:2.0:assertion. Disable attribute encryption for integration endpoints, or implement a decryption step using the IdP private key before parsing.
  • Code adjustment: Add namespace-agnostic parsing by iterating over xml.Name.Space and xml.Name.Local instead of strict struct tags.

Official References