Backport MongoDB hosts array support to 3.x

Backport MongoDB integration fix from main branch to resolve broken
connection strings when using modern configuration format with hosts
array instead of legacy host/port parameters.

The current 3.x template generates malformed MongoDB URIs
(mongodb://user:pass@:/admin with missing host:port) when users
provide modern 'hosts' array parameters. This occurs because the
template expects old-style 'host' and 'port' keys but receives
'hosts' array from modern configurations, causing nil values in
the connection string.

Changes:
- Add dual-path template logic supporting both formats
- Modern configs with 'hosts' array use hosts format (works correctly)
- Legacy configs with 'host'/'port' use connection string (backward compatible)
- Add support for new MongoDB monitoring parameters:
  - dbm: Database Monitoring feature
  - database_autodiscovery: Auto-discovery of databases
  - reported_database_hostname: Custom hostname for metrics
- Update documentation to deprecate host/port in favor of hosts
- Add RSpec tests for modern hosts array format
- Update CHANGELOG for unreleased changes

Template changes:
- Check if server['hosts'] exists and has elements
- If yes: render modern hosts array format with fields
- If no: fall back to legacy connection string format
- Add dbm, database_autodiscovery, reported_database_hostname rendering

Documentation changes:
- Move hosts, dbm, database_autodiscovery, reported_database_hostname to top
- Mark host and port as deprecated with recommendation to use hosts
- Update examples to show modern hosts array format
- Add link to official Datadog MongoDB integration docs

Test changes:
- Add test context for hosts array configuration
- Verify hosts array renders correctly
- Verify all new parameters render correctly
- Maintain backward compatibility with existing tests

Tested:
- pdk validate: PASSED
- Full test suite: 4895 examples, 0 failures, 63 pending
- Syntax validation: PASSED

Refs: 9472fc7
Refs: DataDog#838
Signed-off-by: Jaremy Hatler <j.hatler@xsolla.com>

Author: jhatlerxsolla

CHANGELOG.md

@@ -1,6 +1,10 @@
 Changes
 =======
 
+# Unreleased
+
+* [BUGFIX] Backport MongoDB hosts array support from main to fix broken connection strings with modern configuration format
+
 # 3.24.0 / 2025-02-25
 
 * [BUGFIX] Fix incorrect SSL parameter data type for postgres integration ([#824])

manifests/integrations/mongo.pp

@@ -2,19 +2,26 @@
 #
 # This class will install the necessary configuration for the mongo integration
 #
+# See the sample mongo.d/conf.yaml for all available configuration options
+# https://github.com/DataDog/integrations-core/blob/master/mongo/datadog_checks/mongo/data/conf.yaml.example
+#
 # NOTE: In newer versions of the Datadog Agent, the ssl parameters will be deprecated in favor the tls variants
 #
 # Parameters:
+#   $hosts
+#       Array of hosts host (and optional port number) where the mongod instance is running
+#   $dbm
+#       Enable the Database Monitoring feature
+#   $database_autodiscovery
+#       Enable the Database Autodiscovery feature
+#   $reported_database_hostname
+#       Optional database hostname override the mongodb hostname detected by the Agent from mongodb admin command serverStatus
 #   $additional_metrics
 #       Optional array of additional metrics
 #   $database
 #       Optionally specify database to query. Defaults to 'admin'
-#   $host:
-#       The host mongo is running on. Defaults to '127.0.0.1'
 #   $password
 #       Optionally specify password for connection
-#   $port
-#       The port mongo is running on. Defaults to 27017
 #   $ssl
 #       Optionally enable SSL for connection
 #   $ssl_ca_certs
@@ -37,6 +44,12 @@
 #       Optional array of tags
 #   $username
 #       Optionally specify username for connection
+#   $host:
+#       Deprecated use $hosts instead
+#       The host mongo is running on. Defaults to '127.0.0.1'
+#   $port
+#       Deprecated use $hosts instead
+#       The port mongo is running on. Defaults to 27017
 #
 # Sample Usage (Older Agent Versions):
 #
@@ -73,19 +86,20 @@
 #      {
 #        'additional_metrics' => ['top'],
 #        'database'           => 'database_name',
-#        'host'               => 'localhost',
+#        'hosts'              => ['localhost:27017'],
 #        'password'           => 'mongo_password',
-#        'port'               => '27017',
 #        'tls'                => true,
 #        'tls_ca_file'       => '/path/to/ca.pem',
 #        'tls_allow_invalid_certificates'      => false,
 #        'tls_certificate_key_file'       => '/path/to/combined.pem',
 #        'tags'               => ['optional_tag1', 'optional_tag2'],
 #        'username'           => 'mongo_username',
+#        'dbm'                => true,
+#        'database_autodiscovery' => {'enabled' => true},
+#        'reported_database_hostname' => 'mymongodbhost',
 #      },
 #      {
-#        'host'               => 'localhost',
-#        'port'               => '27018',
+#        'hosts'              => ['localhost:27017'],
 #        'tags'               => [],
 #        'additional_metrics' => [],
 #        'collections'        => [],

spec/classes/datadog_agent_integrations_mongo_spec.rb

@@ -27,6 +27,32 @@
         it { is_expected.to contain_file(conf_file).without_content(%r{tags:}) }
       end
 
+      context 'with one mongo host defined in hosts array' do
+        let(:params) do
+          {
+            servers: [
+              {
+                'hosts' => ['localhost:27017'],
+                'username' => 'user',
+                'password' => 'pass',
+                'database' => 'admin',
+                'dbm' => true,
+                'database_autodiscovery' => { 'enabled' => true },
+                'reported_database_hostname' => 'mongohost',
+              },
+            ],
+          }
+        end
+
+        it { is_expected.to contain_file(conf_file).with_content(%r{- hosts:\s+- localhost:27017}) }
+        it { is_expected.to contain_file(conf_file).with_content(%r{username: user}) }
+        it { is_expected.to contain_file(conf_file).with_content(%r{password: pass}) }
+        it { is_expected.to contain_file(conf_file).with_content(%r{database: admin}) }
+        it { is_expected.to contain_file(conf_file).with_content(%r{dbm: true}) }
+        it { is_expected.to contain_file(conf_file).with_content(%r{database_autodiscovery:\s+enabled: true}) }
+        it { is_expected.to contain_file(conf_file).with_content(%r{reported_database_hostname: mongohost}) }
+      end
+
       context 'with one mongo' do
         let(:params) do
           {

templates/agent-conf.d/mongo.yaml.erb

@@ -4,7 +4,24 @@ init_config:
 
 instances:
 <% @servers.each do |server| -%>
+  <% if !server['hosts'].nil? && server['hosts'].any? -%>
+  - hosts:
+    <%- server['hosts'].each do |host| -%>
+      - <%= host %>
+    <%- end -%>
+    <%- if !server['username'].nil? -%>
+      username: <%= server['username'] %>
+    <%- end -%>
+    <%- if !server['password'].nil? -%>
+      password: <%= server['password'] %>
+    <%- end -%>
+    <%- if !server['database'].nil? -%>
+      database: <%= server['database'] %>
+    <%- end -%>
+  <%- end -%>
+  <% if server['hosts'].nil? -%>
   - server: mongodb://<%= server['username'] %><%= ":" unless server['password'].nil? %><%= server['password'] %><%= "@" unless server['username'].nil? %><%= server['host'] %>:<%= server['port'] %>/<%= server['database'] %>
+  <%- end -%>
   <%- if !server['tags'].nil? && server['tags'].any? -%>
     tags:
     <%- server['tags'].each do |tag| -%>
@@ -50,4 +67,16 @@ instances:
       - <%= collection %>
     <%- end -%>
   <%- end -%>
+  <%- if !server['dbm'].nil? -%>
+    dbm: <%= server['dbm'] %>
+  <%- end -%>
+  <%- if !server['database_autodiscovery'].nil? -%>
+    database_autodiscovery:
+    <%- if !server['database_autodiscovery']['enabled'].nil? -%>
+      enabled: <%= server['database_autodiscovery']['enabled'] %>
+    <%- end -%>
+  <%- end -%>
+  <%- if !server['reported_database_hostname'].nil? -%>
+    reported_database_hostname: <%= server['reported_database_hostname'] %>
+  <%- end -%>
 <% end -%>