postgres provider: add support for "allow" and "prefer" SSL modes

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

docs/full-configuration.md

@@ -241,7 +241,7 @@ The configuration file contains the following sections:
   - `port`, integer. Database port. Leave empty for drivers `sqlite`, `bolt` and `memory`
   - `username`, string. Database user. Leave empty for drivers `sqlite`, `bolt` and `memory`
   - `password`, string. Database password. Leave empty for drivers `sqlite`, `bolt` and `memory`
-  - `sslmode`, integer. Used for drivers `mysql` and `postgresql`. 0 disable TLS connections, 1 require TLS, 2 set TLS mode to `verify-ca` for driver `postgresql` and `skip-verify` for driver `mysql`, 3 set TLS mode to `verify-full` for driver `postgresql` and `preferred` for driver `mysql`
+  - `sslmode`, integer. Used for drivers `mysql` and `postgresql`. 0 disable TLS connections, 1 require TLS, 2 set TLS mode to `verify-ca` for driver `postgresql` and `skip-verify` for driver `mysql`, 3 set TLS mode to `verify-full` for driver `postgresql` and `preferred` for driver `mysql`, 4 set the TLS mode to `prefer` for driver `postgresql`, 5 set the TLS mode to `allow` for driver `postgresql`
   - `root_cert`, string. Path to the root certificate authority used to verify that the server certificate was signed by a trusted CA
   - `disable_sni`, boolean. Allows to opt out Server Name Indication (SNI) for TLS connections. Default: `false`
   - `target_session_attrs`, string. This is a `postgresql` and `cockroachdb` specific option. It determines whether the session must have certain properties to be acceptable. It's typically used in combination with multiple host names to select the first acceptable alternative among several hosts. Supported values: `any`, `read-write`, `read-only`, `primary`, `standby`, `prefer-standby`. If empty, `any` is assumed. If you explicitly set `any` the connections will be randomly distributed among the specified hosts

go.mod

@@ -36,7 +36,7 @@ require (
 	github.com/hashicorp/go-hclog v1.5.0
 	github.com/hashicorp/go-plugin v1.4.10
 	github.com/hashicorp/go-retryablehttp v0.7.4
-	github.com/jackc/pgx/v5 v5.4.2
+	github.com/jackc/pgx/v5 v5.4.3
 	github.com/jlaffaye/ftp v0.0.0-20201112195030-9aae4d151126
 	github.com/klauspost/compress v1.16.7
 	github.com/lestrrat-go/jwx/v2 v2.0.11

go.sum

@@ -307,8 +307,8 @@ github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsI
 github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
 github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a h1:bbPeKD0xmW/Y25WS6cokEszi5g+S0QxI/d45PkRi7Nk=
 github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
-github.com/jackc/pgx/v5 v5.4.2 h1:u1gmGDwbdRUZiwisBm/Ky2M14uQyUP65bG8+20nnyrg=
-github.com/jackc/pgx/v5 v5.4.2/go.mod h1:q6iHT8uDNXWiFNOlRqJzBTaSH3+2xCXkokxHZC5qWFY=
+github.com/jackc/pgx/v5 v5.4.3 h1:cxFyXhxlvAifxnkKKdlxv8XqUf59tDlYjnV5YYfsJJY=
+github.com/jackc/pgx/v5 v5.4.3/go.mod h1:Ig06C2Vu0t5qXC60W8sqIthScaEnFvojjj9dSljmHRA=
 github.com/jhump/protoreflect v1.6.0 h1:h5jfMVslIg6l29nsMs0D8Wj17RDVdNYti0vDN/PZZoE=
 github.com/jmespath/go-jmespath v0.4.0 h1:BEgLn5cpjn8UN1mAw4NjwDrS35OdebyEtFe+9YPoQUg=
 github.com/jmespath/go-jmespath v0.4.0/go.mod h1:T8mJZnbsbmF+m6zOOFylbeCJqk5+pHWvzYPziyZiYoo=

internal/dataprovider/dataprovider.go

@@ -3414,6 +3414,10 @@ func getSSLMode() string {
 			return "verify-ca"
 		case 3:
 			return "verify-full"
+		case 4:
+			return "prefer"
+		case 5:
+			return "allow"
 		}
 	} else if config.Driver == MySQLDataProviderName {
 		if config.requireCustomTLSForMySQL() {