Adding a Connection to Google Spanner

To add a connection to Google Spanner:

1. In the application console, navigate to the Connections page.
2. At the Add Connections panel, select the icon for the connection you want to add.
3. If the Google Spanner icon is not available, click the Add More icon to download and install the Google Spanner connector from the CData site.

For required properties, see the Settings tab.

For connection properties that are not typically required, see the Advanced tab.

Connecting to Google Spanner

By default, the CData Sync App connects to all available projects in your database. To limit the scope of your connection, set combinations of the following properties:

• InstanceId: The ID of the Google Spanner instance to which you are connecting.
• Database: The name of the Google Spanner database to connect to.
• ProjectId: The ID of the project where your Google Spanner instance resides.

Authenticating to Google Spanner

The Sync App supports using user accounts and GCP instance accounts for authentication.

The following sections discuss the available authentication schemes for Google Spanner:

• User Accounts (OAuth)
• Service Account (OAuthJWT)
• GCP Instance Account

User Accounts (OAuth)

AuthScheme must be set to OAuth in all user account flows.

Web Applications

When connecting via a Web application, you need to create and register a custom OAuth application with Google Spanner. You can then use the Sync App to acquire and manage the OAuth token values. See Creating a Custom OAuth App for more information about custom applications.

Get an OAuth Access Token

Set the following connection properties to obtain the OAuthAccessToken:

• OAuthClientId: Set this to the Client Id in your application settings.
• OAuthClientSecret: Set this to the Client Secret in your application settings.

Then call stored procedures to complete the OAuth exchange:

1. Call the GetOAuthAuthorizationURL stored procedure. Set the CallbackURL input to the Callback URL you specified in your application settings. The stored procedure returns the URL to the OAuth endpoint.
2. Navigate to the URL that the stored procedure returned in Step 1. Log in to the custom OAuth application and authorize the web application. Once authenticated, the browser redirects you to the callback URL.
3. Call the GetOAuthAccessToken stored procedure. Set AuthMode to WEB and the Verifier input to the "code" parameter in the query string of the callback URL.

Once you have obtained the access and refresh tokens, you can connect to data and refresh the OAuth access token either automatically or manually.

Automatic Refresh of the OAuth Access Token

To have the driver automatically refresh the OAuth access token, set the following on the first data connection:

• InitiateOAuth: Set this to REFRESH.
• OAuthClientId: Set this to the Client Id in your application settings.
• OAuthClientSecret: Set this to the Client Secret in your application settings.
• OAuthAccessToken: Set this to the access token returned by GetOAuthAccessToken.
• OAuthRefreshToken: Set this to the refresh token returned by GetOAuthAccessToken.
• OAuthSettingsLocation: Set this to the location where the Sync App saves the OAuth token values, which persist across connections.

On subsequent data connections, the values for OAuthAccessToken and OAuthRefreshToken are taken from OAuthSettingsLocation.

Manual Refresh of the OAuth Access Token

The only value needed to manually refresh the OAuth access token when connecting to data is the OAuth refresh token.

Use the RefreshOAuthAccessToken stored procedure to manually refresh the OAuthAccessToken after the ExpiresIn parameter value returned by GetOAuthAccessToken has elapsed, then set the following connection properties:

• OAuthClientId: Set this to the Client Id in your application settings.
• OAuthClientSecret: Set this to the Client Secret in your application settings.

Then call RefreshOAuthAccessToken with OAuthRefreshToken set to the OAuth refresh token returned by GetOAuthAccessToken. After the new tokens have been retrieved, open a new connection by setting the OAuthAccessToken property to the value returned by RefreshOAuthAccessToken.

Finally, store the OAuth refresh token so that you can use it to manually refresh the OAuth access token after it has expired.

Headless Machines

To configure the driver to use OAuth with a user account on a headless machine, you need to authenticate on another device that has an internet browser.

1. Choose one of two options:
   • Option 1: Obtain the OAuthVerifier value as described in "Obtain and Exchange a Verifier Code" below.
   • Option 2: Install the Sync App on a machine with an Internet browser and transfer the OAuth authentication values after you authenticate through the usual browser-based flow, as described in "Transfer OAuth Settings" below.
2. Then configure the Sync App to automatically refresh the access token on the headless machine.

Option 1: Obtain and Exchange a Verifier Code

To obtain a verifier code, you must authenticate at the OAuth authorization URL.

Follow the steps below to authenticate from the machine with an Internet browser and obtain the OAuthVerifier connection property.

1. Choose one of these options:
   • If you are using the Embedded OAuth Application click Google Spanner OAuth endpoint to open the endpoint in your browser.
   • If you are using a custom OAuth application, create the Authorization URL by setting the following properties:
     • InitiateOAuth: Set to OFF.
     • OAuthClientId: Set to the client Id assigned when you registered your application.
     • OAuthClientSecret: Set to the client secret assigned when you registered your application.
     Then call the GetOAuthAuthorizationURL stored procedure with the appropriate CallbackURL. Open the URL returned by the stored procedure in a browser.
2. Log in and grant permissions to the Sync App. You are then redirected to the callback URL, which contains the verifier code.
3. Save the value of the verifier code. Later you will set this in the OAuthVerifier connection property.

Next, you need to exchange the OAuth verifier code for OAuth refresh and access tokens. Set the following properties:

On the headless machine, set the following connection properties to obtain the OAuth authentication values:

• InitiateOAuth: Set this to REFRESH.
• OAuthVerifier: Set this to the verifier code.
• OAuthClientId: (custom applications only) Set this to the Client Id in your custom OAuth application settings.
• OAuthClientSecret: (custom applications only) Set this to the Client Secret in the custom OAuth application settings.
• OAuthSettingsLocation: Set this to persist the encrypted OAuth authentication values to the specified location.

After the OAuth settings file is generated, you need to re-set the following properties to connect:

• InitiateOAuth: Set this to REFRESH.
• OAuthClientId: (custom applications only) Set this to the client Id assigned when you registered your application.
• OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
• OAuthSettingsLocation: Set this to the location containing the encrypted OAuth authentication values. Make sure this location gives read and write permissions to the Sync App to enable the automatic refreshing of the access token.

Option 2: Transfer OAuth Settings

Prior to connecting on a headless machine, you need to create and install a connection with the driver on a device that supports an Internet browser. Set the connection properties as described in "Desktop Applications" above.

After completing the instructions in "Desktop Applications", the resulting authentication values are encrypted and written to the location specified by OAuthSettingsLocation. The default filename is OAuthSettings.txt.

Once you have successfully tested the connection, copy the OAuth settings file to your headless machine.

On the headless machine, set the following connection properties to connect to data:

• InitiateOAuth: Set this to REFRESH.
• OAuthClientId: (custom applications only) Set this to the client Id assigned when you registered your application.
• OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
• OAuthSettingsLocation: Set this to the location of your OAuth settings file. Make sure this location gives read and write permissions to the Sync App to enable the automatic refreshing of the access token.

GCP Instance Accounts

When running on a GCP virtual machine, the Sync App can authenticate using a service account tied to the virtual machine. To use this mode, set AuthScheme to GCPInstanceAccount.

This section details a selection of advanced features of the Google Spanner Sync App.

User Defined Views

The Sync App allows you to define virtual tables, called user defined views, whose contents are decided by a pre-configured query. These views are useful when you cannot directly control queries being issued to the drivers. See User Defined Views for an overview of creating and configuring custom views.

SSL Configuration

Use SSL Configuration to adjust how Sync App handles TLS/SSL certificate negotiations. You can choose from various certificate formats; see the SSLServerCert property under "Connection String Options" for more information.

Firewall and Proxy

Configure the Sync App for compliance with Firewall and Proxy, including Windows proxies and HTTP proxies. You can also set up tunnel connections.

Query Processing

The Sync App offloads as much of the SELECT statement processing as possible to Google Spanner and then processes the rest of the query in memory (client-side).

See Query Processing for more information.

Logging

See Logging for an overview of configuration settings that can be used to refine CData logging. For basic logging, you only need to set two connection properties, but there are numerous features that support more refined logging, where you can select subsets of information to be logged using the LogModules connection property.

Customizing the SSL Configuration

By default, the Sync App attempts to negotiate SSL/TLS by checking the server's certificate against the system's trusted certificate store.

To specify another certificate, see the SSLServerCert property for the available formats to do so.

Connecting Through a Firewall or Proxy

HTTP Proxies

To connect through the Windows system proxy, you do not need to set any additional connection properties. To connect to other proxies, set ProxyAutoDetect to false.

In addition, to authenticate to an HTTP proxy, set ProxyAuthScheme, ProxyUser, and ProxyPassword, in addition to ProxyServer and ProxyPort.

Other Proxies

Set the following properties:

• To use a proxy-based firewall, set FirewallType, FirewallServer, and FirewallPort.
• To tunnel the connection, set FirewallType to TUNNEL.
• To authenticate, specify FirewallUser and FirewallPassword.
• To authenticate to a SOCKS proxy, additionally set FirewallType to SOCKS5.

The CData Sync App models the data as defined within Google Spanner for the Project and Instance configured.

The connection string properties are the various options that can be used to establish a connection. This section provides a complete list of the options you can configure in the connection string for this provider. Click the links for further details.

For more information on establishing a connection, see Establishing a Connection.

Authentication

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Property	Description
AuthScheme	The type of authentication to use when connecting to Google Spanner.
InstanceId	The id of the Google Spanner instance to which you are connecting.
Database	The name of the Google Spanner database to connect to.
DatabaseDialect	The dialect type of the connected database.
ProjectId	The id of the project where your Google Spanner instance resides.
UseGrpcEndpoint	Whether to use the Grpc endpoint or not.

OAuth

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Property	Description
OAuthClientId	The client Id assigned when you register your application with an OAuth authorization server.
OAuthClientSecret	The client secret assigned when you register your application with an OAuth authorization server.

JWT OAuth

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Property	Description
OAuthJWTCert	The JWT Certificate store.
OAuthJWTCertType	The type of key store containing the JWT Certificate.
OAuthJWTCertPassword	The password for the OAuth JWT certificate.
OAuthJWTCertSubject	The subject of the OAuth JWT certificate.
OAuthJWTIssuer	The issuer of the Java Web Token.
OAuthJWTSubject	The user subject for which the application is requesting delegated access.

SSL

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Property	Description
SSLServerCert	The certificate to be accepted from the server when connecting using TLS/SSL.

Firewall

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Property	Description
FirewallType	The protocol used by a proxy-based firewall.
FirewallServer	The name or IP address of a proxy-based firewall.
FirewallPort	The TCP port for a proxy-based firewall.
FirewallUser	The user name to use to authenticate with a proxy-based firewall.
FirewallPassword	A password used to authenticate to a proxy-based firewall.

Proxy

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Property	Description
ProxyAutoDetect	This indicates whether to use the system proxy settings or not.
ProxyServer	The hostname or IP address of a proxy to route HTTP traffic through.
ProxyPort	The TCP port the ProxyServer proxy is running on.
ProxyAuthScheme	The authentication type to use to authenticate to the ProxyServer proxy.
ProxyUser	A user name to be used to authenticate to the ProxyServer proxy.
ProxyPassword	A password to be used to authenticate to the ProxyServer proxy.
ProxySSLType	The SSL type to use when connecting to the ProxyServer proxy.
ProxyExceptions	A semicolon separated list of destination hostnames or IPs that are exempt from connecting through the ProxyServer .

Logging

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Property	Description
LogModules	Core modules to be included in the log file.

Schema

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Property	Description
Location	A path to the directory that contains the schema files defining tables, views, and stored procedures.
BrowsableSchemas	This property restricts the schemas reported to a subset of the available schemas. For example, BrowsableSchemas=SchemaA,SchemaB,SchemaC.
Tables	This property restricts the tables reported to a subset of the available tables. For example, Tables=TableA,TableB,TableC.
Views	Restricts the views reported to a subset of the available tables. For example, Views=ViewA,ViewB,ViewC.
Schema	The schema which will be used by default.

Miscellaneous

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Property	Description
DataBoostEnabled	For the case of a partitioned query, setting this this field to true means the request is executed with Spanner Data Boost independent compute resources.
MaxRows	Limits the number of rows returned when no aggregation or GROUP BY is used in the query. This takes precedence over LIMIT clauses.
Other	These hidden properties are used only in specific use cases.
PseudoColumns	This property indicates whether or not to include pseudo columns as columns to the table.
QueryPartitionMode	Configures what type of query the provider creates and how it extracts the data from the source.
QueryPassthrough	This option passes the query to the Google Spanner server as is.
Timeout	The value in seconds until the timeout error is thrown, canceling the operation.
UserDefinedViews	A filepath pointing to the JSON configuration file containing your custom views.

This section provides a complete list of the Authentication properties you can configure in the connection string for this provider.

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Property	Description
AuthScheme	The type of authentication to use when connecting to Google Spanner.
InstanceId	The id of the Google Spanner instance to which you are connecting.
Database	The name of the Google Spanner database to connect to.
DatabaseDialect	The dialect type of the connected database.
ProjectId	The id of the project where your Google Spanner instance resides.
UseGrpcEndpoint	Whether to use the Grpc endpoint or not.

The type of authentication to use when connecting to Google Spanner.

Remarks

• Auto: Lets the driver decide automatically based on the other connection properties you have set.
• OAuth: Set this to perform OAuth authentication using a standard user account.
• OAuthJWT: Set this to perform OAuth authentication using an OAuth service account.
• GCPInstanceAccount: Set this to get Access Token from Google Cloud Platform instance.

The id of the Google Spanner instance to which you are connecting.

Remarks

The address of the Google Spanner instance to which you are connecting. You can find this value at instance overview. Instances will be listed once you select Spanner from the Google Cloud Console Menu.

The name of the Google Spanner database to connect to.

Remarks

The name of the Google Spanner database to connect to.

The dialect type of the connected database.

Remarks

The dialect type of the connected database.

DatabaseDialect controls the dialect to work with. The default is GoogleStandardSQL, the Spanner native dialect. Set this property to PostgreSQL to use that dialect instead.

The id of the project where your Google Spanner instance resides.

Remarks

The id of the project where your Google Spanner instance resides. You can find this value by going to Google Cloud Console and clicking the project name at the top left screen. The ProjectId is displayed on the Id column of the matching project.

Whether to use the Grpc endpoint or not.

Remarks

This property determines whether or not the Grpc endpoint will be used. Most proxies will not work with the Grpc endpoint. If set to false, the protobuf endpoint will be used. The latter has issues with NULL values, but proxies will work on it.

This section provides a complete list of the OAuth properties you can configure in the connection string for this provider.

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Property	Description
OAuthClientId	The client Id assigned when you register your application with an OAuth authorization server.
OAuthClientSecret	The client secret assigned when you register your application with an OAuth authorization server.

The client Id assigned when you register your application with an OAuth authorization server.

Remarks

As part of registering an OAuth application, you will receive the OAuthClientId value, sometimes also called a consumer key, and a client secret, the OAuthClientSecret.

The client secret assigned when you register your application with an OAuth authorization server.

Remarks

As part of registering an OAuth application, you will receive the OAuthClientId, also called a consumer key. You will also receive a client secret, also called a consumer secret. Set the client secret in the OAuthClientSecret property.

This section provides a complete list of the JWT OAuth properties you can configure in the connection string for this provider.

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Property	Description
OAuthJWTCert	The JWT Certificate store.
OAuthJWTCertType	The type of key store containing the JWT Certificate.
OAuthJWTCertPassword	The password for the OAuth JWT certificate.
OAuthJWTCertSubject	The subject of the OAuth JWT certificate.
OAuthJWTIssuer	The issuer of the Java Web Token.
OAuthJWTSubject	The user subject for which the application is requesting delegated access.

The JWT Certificate store.

Remarks

The name of the certificate store for the client certificate.

The OAuthJWTCertType field specifies the type of the certificate store specified by OAuthJWTCert. If the store is password protected, specify the password in OAuthJWTCertPassword.

OAuthJWTCert is used in conjunction with the OAuthJWTCertSubject field in order to specify client certificates. If OAuthJWTCert has a value, and OAuthJWTCertSubject is set, a search for a certificate is initiated. Please refer to the OAuthJWTCertSubject field for details.

Designations of certificate stores are platform-dependent.

The following are designations of the most common User and Machine certificate stores in Windows:

MY	A certificate store holding personal certificates with their associated private keys.
CA	Certifying authority certificates.
ROOT	Root certificates.
SPC	Software publisher certificates.

In Java, the certificate store normally is a file containing certificates and optional private keys.

When the certificate store type is PFXFile, this property must be set to the name of the file. When the type is PFXBlob, the property must be set to the binary contents of a PFX file (i.e. PKCS12 certificate store).

The type of key store containing the JWT Certificate.

Remarks

This property can take one of the following values:

USER	For Windows, this specifies that the certificate store is a certificate store owned by the current user. Note: This store type is not available in Java.
MACHINE	For Windows, this specifies that the certificate store is a machine store. Note: this store type is not available in Java.
PFXFILE	The certificate store is the name of a PFX (PKCS12) file containing certificates.
PFXBLOB	The certificate store is a string (base-64-encoded) representing a certificate store in PFX (PKCS12) format.
JKSFILE	The certificate store is the name of a Java key store (JKS) file containing certificates. Note: this store type is only available in Java.
JKSBLOB	The certificate store is a string (base-64-encoded) representing a certificate store in Java key store (JKS) format. Note: this store type is only available in Java.
PEMKEY_FILE	The certificate store is the name of a PEM-encoded file that contains a private key and an optional certificate.
PEMKEY_BLOB	The certificate store is a string (base64-encoded) that contains a private key and an optional certificate.
PUBLIC_KEY_FILE	The certificate store is the name of a file that contains a PEM- or DER-encoded public key certificate.
PUBLIC_KEY_BLOB	The certificate store is a string (base-64-encoded) that contains a PEM- or DER-encoded public key certificate.
SSHPUBLIC_KEY_FILE	The certificate store is the name of a file that contains an SSH-style public key.
SSHPUBLIC_KEY_BLOB	The certificate store is a string (base-64-encoded) that contains an SSH-style public key.
P7BFILE	The certificate store is the name of a PKCS7 file containing certificates.
PPKFILE	The certificate store is the name of a file that contains a PPK (PuTTY Private Key).
XMLFILE	The certificate store is the name of a file that contains a certificate in XML format.
XMLBLOB	The certificate store is a string that contains a certificate in XML format.
GOOGLEJSON	The certificate store is the name of a JSON file containing the service account information. Only valid when connecting to a Google service.
GOOGLEJSONBLOB	The certificate store is a string that contains the service account JSON. Only valid when connecting to a Google service.

The password for the OAuth JWT certificate.

Remarks

If the certificate store is of a type that requires a password, this property is used to specify that password in order to open the certificate store.

This is not required when using the GOOGLEJSON OAuthJWTCertType. Google JSON keys are not encrypted.

The subject of the OAuth JWT certificate.

Remarks

When loading a certificate the subject is used to locate the certificate in the store.

If an exact match is not found, the store is searched for subjects containing the value of the property.

If a match is still not found, the property is set to an empty string, and no certificate is selected.

The special value "*" picks the first certificate in the certificate store.

The certificate subject is a comma separated list of distinguished name fields and values. For instance "CN=www.server.com, OU=test, C=US, [email protected]". Common fields and their meanings are displayed below.

Field	Meaning
CN	Common Name. This is commonly a host name like www.server.com.
O	Organization
OU	Organizational Unit
L	Locality
S	State
C	Country
E	Email Address

If a field value contains a comma it must be quoted.

The issuer of the Java Web Token.

Remarks

The issuer of the Java Web Token. Enter the value of a delegated user Email Address.

This is not required when using the GOOGLEJSON OAuthJWTCertType. Google JSON keys contain a copy of the issuer account.

The issuer of the Java Web Token. Enter the value of a delegated user Email Address.

This is not required when using the GOOGLEJSON OAuthJWTCertType. Google JSON keys contain a copy of the issuer account.

The user subject for which the application is requesting delegated access.

Remarks

The user subject for which the application is requesting delegated access. Enter the value of the Service Account Email.

The user subject for which the application is requesting delegated access. Enter the value of the Service Account Email.

This section provides a complete list of the SSL properties you can configure in the connection string for this provider.

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Property	Description
SSLServerCert	The certificate to be accepted from the server when connecting using TLS/SSL.

The certificate to be accepted from the server when connecting using TLS/SSL.

Remarks

If using a TLS/SSL connection, this property can be used to specify the TLS/SSL certificate to be accepted from the server. Any other certificate that is not trusted by the machine is rejected.

This property can take the following forms:

Description	Example
A full PEM Certificate (example shortened for brevity)	-----BEGIN CERTIFICATE----- MIIChTCCAe4CAQAwDQYJKoZIhv......Qw== -----END CERTIFICATE-----
A path to a local file containing the certificate	C:\cert.cer
The public key (example shortened for brevity)	-----BEGIN RSA PUBLIC KEY----- MIGfMA0GCSq......AQAB -----END RSA PUBLIC KEY-----
The MD5 Thumbprint (hex values can also be either space or colon separated)	ecadbdda5a1529c58a1e9e09828d70e4
The SHA1 Thumbprint (hex values can also be either space or colon separated)	34a929226ae0819f2ec14b4a3d904f801cbb150d

If not specified, any certificate trusted by the machine is accepted.

Use '*' to signify to accept all certificates. Note that this is not recommended due to security concerns.

This section provides a complete list of the Firewall properties you can configure in the connection string for this provider.

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Property	Description
FirewallType	The protocol used by a proxy-based firewall.
FirewallServer	The name or IP address of a proxy-based firewall.
FirewallPort	The TCP port for a proxy-based firewall.
FirewallUser	The user name to use to authenticate with a proxy-based firewall.
FirewallPassword	A password used to authenticate to a proxy-based firewall.

The protocol used by a proxy-based firewall.

Remarks

This property specifies the protocol that the Sync App will use to tunnel traffic through the FirewallServer proxy. Note that by default, the Sync App connects to the system proxy; to disable this behavior and connect to one of the following proxy types, set ProxyAutoDetect to false.

Type	Default Port	Description
TUNNEL	80	When this is set, the Sync App opens a connection to Google Spanner and traffic flows back and forth through the proxy.
SOCKS4	1080	When this is set, the Sync App sends data through the SOCKS 4 proxy specified by FirewallServer and FirewallPort and passes the FirewallUser value to the proxy, which determines if the connection request should be granted.
SOCKS5	1080	When this is set, the Sync App sends data through the SOCKS 5 proxy specified by FirewallServer and FirewallPort. If your proxy requires authentication, set FirewallUser and FirewallPassword to credentials the proxy recognizes.

To connect to HTTP proxies, use ProxyServer and ProxyPort. To authenticate to HTTP proxies, use ProxyAuthScheme, ProxyUser, and ProxyPassword.

The name or IP address of a proxy-based firewall.

Remarks

This property specifies the IP address, DNS name, or host name of a proxy allowing traversal of a firewall. The protocol is specified by FirewallType: Use FirewallServer with this property to connect through SOCKS or do tunneling. Use ProxyServer to connect to an HTTP proxy.

Note that the Sync App uses the system proxy by default. To use a different proxy, set ProxyAutoDetect to false.

The TCP port for a proxy-based firewall.

Remarks

This specifies the TCP port for a proxy allowing traversal of a firewall. Use FirewallServer to specify the name or IP address. Specify the protocol with FirewallType.

The user name to use to authenticate with a proxy-based firewall.

Remarks

The FirewallUser and FirewallPassword properties are used to authenticate against the proxy specified in FirewallServer and FirewallPort, following the authentication method specified in FirewallType.

A password used to authenticate to a proxy-based firewall.

Remarks

This property is passed to the proxy specified by FirewallServer and FirewallPort, following the authentication method specified by FirewallType.

This section provides a complete list of the Proxy properties you can configure in the connection string for this provider.

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Property	Description
ProxyAutoDetect	This indicates whether to use the system proxy settings or not.
ProxyServer	The hostname or IP address of a proxy to route HTTP traffic through.
ProxyPort	The TCP port the ProxyServer proxy is running on.
ProxyAuthScheme	The authentication type to use to authenticate to the ProxyServer proxy.
ProxyUser	A user name to be used to authenticate to the ProxyServer proxy.
ProxyPassword	A password to be used to authenticate to the ProxyServer proxy.
ProxySSLType	The SSL type to use when connecting to the ProxyServer proxy.
ProxyExceptions	A semicolon separated list of destination hostnames or IPs that are exempt from connecting through the ProxyServer .

This indicates whether to use the system proxy settings or not.

Remarks

This takes precedence over other proxy settings, so you'll need to set ProxyAutoDetect to FALSE in order use custom proxy settings.

To connect to an HTTP proxy, see ProxyServer. For other proxies, such as SOCKS or tunneling, see FirewallType.

The hostname or IP address of a proxy to route HTTP traffic through.

Remarks

The hostname or IP address of a proxy to route HTTP traffic through. The Sync App can use the HTTP, Windows (NTLM), or Kerberos authentication types to authenticate to an HTTP proxy.

If you need to connect through a SOCKS proxy or tunnel the connection, see FirewallType.

By default, the Sync App uses the system proxy. If you need to use another proxy, set ProxyAutoDetect to false.

The TCP port the ProxyServer proxy is running on.

Remarks

The port the HTTP proxy is running on that you want to redirect HTTP traffic through. Specify the HTTP proxy in ProxyServer. For other proxy types, see FirewallType.

The authentication type to use to authenticate to the ProxyServer proxy.

Remarks

This value specifies the authentication type to use to authenticate to the HTTP proxy specified by ProxyServer and ProxyPort.

Note that the Sync App will use the system proxy settings by default, without further configuration needed; if you want to connect to another proxy, you will need to set ProxyAutoDetect to false, in addition to ProxyServer and ProxyPort. To authenticate, set ProxyAuthScheme and set ProxyUser and ProxyPassword, if needed.

The authentication type can be one of the following:

• BASIC: The Sync App performs HTTP BASIC authentication.
• DIGEST: The Sync App performs HTTP DIGEST authentication.
• NEGOTIATE: The Sync App retrieves an NTLM or Kerberos token based on the applicable protocol for authentication.
• PROPRIETARY: The Sync App does not generate an NTLM or Kerberos token. You must supply this token in the Authorization header of the HTTP request.

If you need to use another authentication type, such as SOCKS 5 authentication, see FirewallType.

A user name to be used to authenticate to the ProxyServer proxy.

Remarks

The ProxyUser and ProxyPassword options are used to connect and authenticate against the HTTP proxy specified in ProxyServer.

You can select one of the available authentication types in ProxyAuthScheme. If you are using HTTP authentication, set this to the user name of a user recognized by the HTTP proxy. If you are using Windows or Kerberos authentication, set this property to a user name in one of the following formats:

user@domain
domain\user

A password to be used to authenticate to the ProxyServer proxy.

Remarks

This property is used to authenticate to an HTTP proxy server that supports NTLM (Windows), Kerberos, or HTTP authentication. To specify the HTTP proxy, you can set ProxyServer and ProxyPort. To specify the authentication type, set ProxyAuthScheme.

If you are using HTTP authentication, additionally set ProxyUser and ProxyPassword to HTTP proxy.

If you are using NTLM authentication, set ProxyUser and ProxyPassword to your Windows password. You may also need these to complete Kerberos authentication.

For SOCKS 5 authentication or tunneling, see FirewallType.

By default, the Sync App uses the system proxy. If you want to connect to another proxy, set ProxyAutoDetect to false.

The SSL type to use when connecting to the ProxyServer proxy.

Remarks

This property determines when to use SSL for the connection to an HTTP proxy specified by ProxyServer. This value can be AUTO, ALWAYS, NEVER, or TUNNEL. The applicable values are the following:

AUTO	Default setting. If the URL is an HTTPS URL, the Sync App will use the TUNNEL option. If the URL is an HTTP URL, the component will use the NEVER option.
ALWAYS	The connection is always SSL enabled.
NEVER	The connection is not SSL enabled.
TUNNEL	The connection is through a tunneling proxy. The proxy server opens a connection to the remote host and traffic flows back and forth through the proxy.

A semicolon separated list of destination hostnames or IPs that are exempt from connecting through the ProxyServer .

Remarks

The ProxyServer is used for all addresses, except for addresses defined in this property. Use semicolons to separate entries.

Note that the Sync App uses the system proxy settings by default, without further configuration needed; if you want to explicitly configure proxy exceptions for this connection, you need to set ProxyAutoDetect = false, and configure ProxyServer and ProxyPort. To authenticate, set ProxyAuthScheme and set ProxyUser and ProxyPassword, if needed.

This section provides a complete list of the Logging properties you can configure in the connection string for this provider.

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Property	Description
LogModules	Core modules to be included in the log file.

Core modules to be included in the log file.

Remarks

Only the modules specified (separated by ';') will be included in the log file. By default all modules are included.

See the Logging page for an overview.

This section provides a complete list of the Schema properties you can configure in the connection string for this provider.

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Property	Description
Location	A path to the directory that contains the schema files defining tables, views, and stored procedures.
BrowsableSchemas	This property restricts the schemas reported to a subset of the available schemas. For example, BrowsableSchemas=SchemaA,SchemaB,SchemaC.
Tables	This property restricts the tables reported to a subset of the available tables. For example, Tables=TableA,TableB,TableC.
Views	Restricts the views reported to a subset of the available tables. For example, Views=ViewA,ViewB,ViewC.
Schema	The schema which will be used by default.

A path to the directory that contains the schema files defining tables, views, and stored procedures.

Remarks

The path to a directory which contains the schema files for the Sync App (.rsd files for tables and views, .rsb files for stored procedures). The folder location can be a relative path from the location of the executable. The Location property is only needed if you want to customize definitions (for example, change a column name, ignore a column, and so on) or extend the data model with new tables, views, or stored procedures.

If left unspecified, the default location is "%APPDATA%\\CData\\GoogleSpanner Data Provider\\Schema" with %APPDATA% being set to the user's configuration directory:

Platform	%APPDATA%
Windows	The value of the APPDATA environment variable
Linux	~/.config

This property restricts the schemas reported to a subset of the available schemas. For example, BrowsableSchemas=SchemaA,SchemaB,SchemaC.

Remarks

Listing the schemas from databases can be expensive. Providing a list of schemas in the connection string improves the performance.

This property restricts the tables reported to a subset of the available tables. For example, Tables=TableA,TableB,TableC.

Remarks

Listing the tables from some databases can be expensive. Providing a list of tables in the connection string improves the performance of the Sync App.

This property can also be used as an alternative to automatically listing views if you already know which ones you want to work with and there would otherwise be too many to work with.

Specify the tables you want in a comma-separated list. Each table should be a valid SQL identifier with any special characters escaped using square brackets, double-quotes or backticks. For example, Tables=TableA,[TableB/WithSlash],WithCatalog.WithSchema.`TableC With Space`.

Note that when connecting to a data source with multiple schemas or catalogs, you will need to provide the fully qualified name of the table in this property, as in the last example here, to avoid ambiguity between tables that exist in multiple catalogs or schemas.

Restricts the views reported to a subset of the available tables. For example, Views=ViewA,ViewB,ViewC.

Remarks

Listing the views from some databases can be expensive. Providing a list of views in the connection string improves the performance of the Sync App.

This property can also be used as an alternative to automatically listing views if you already know which ones you want to work with and there would otherwise be too many to work with.

Specify the views you want in a comma-separated list. Each view should be a valid SQL identifier with any special characters escaped using square brackets, double-quotes or backticks. For example, Views=ViewA,[ViewB/WithSlash],WithCatalog.WithSchema.`ViewC With Space`.

Note that when connecting to a data source with multiple schemas or catalogs, you will need to provide the fully qualified name of the table in this property, as in the last example here, to avoid ambiguity between tables that exist in multiple catalogs or schemas.

The schema which will be used by default.

Remarks

The schema which will be used by default.

This section provides a complete list of the Miscellaneous properties you can configure in the connection string for this provider.

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Property	Description
DataBoostEnabled	For the case of a partitioned query, setting this this field to true means the request is executed with Spanner Data Boost independent compute resources.
MaxRows	Limits the number of rows returned when no aggregation or GROUP BY is used in the query. This takes precedence over LIMIT clauses.
Other	These hidden properties are used only in specific use cases.
PseudoColumns	This property indicates whether or not to include pseudo columns as columns to the table.
QueryPartitionMode	Configures what type of query the provider creates and how it extracts the data from the source.
QueryPassthrough	This option passes the query to the Google Spanner server as is.
Timeout	The value in seconds until the timeout error is thrown, canceling the operation.
UserDefinedViews	A filepath pointing to the JSON configuration file containing your custom views.

For the case of a partitioned query, setting this this field to true means the request is executed with Spanner Data Boost independent compute resources.

Remarks

For the case of a partitioned query, setting this this field to true means the request is executed with Spanner Data Boost independent compute resources.

Limits the number of rows returned when no aggregation or GROUP BY is used in the query. This takes precedence over LIMIT clauses.

Remarks

Limits the number of rows returned when no aggregation or GROUP BY is used in the query. This takes precedence over LIMIT clauses.

These hidden properties are used only in specific use cases.

Remarks

The properties listed below are available for specific use cases. Normal driver use cases and functionality should not require these properties.

Specify multiple properties in a semicolon-separated list.

Integration and Formatting

DefaultColumnSize	Sets the default length of string fields when the data source does not provide column length in the metadata. The default value is 2000.
ConvertDateTimeToGMT	Determines whether to convert date-time values to GMT, instead of the local time of the machine.
RecordToFile=filename	Records the underlying socket data transfer to the specified file.

This property indicates whether or not to include pseudo columns as columns to the table.

Remarks

This setting is particularly helpful in Entity Framework, which does not allow you to set a value for a pseudo column unless it is a table column. The value of this connection setting is of the format "Table1=Column1, Table1=Column2, Table2=Column3". You can use the "*" character to include all tables and all columns; for example, "*=*".

Configures what type of query the provider creates and how it extracts the data from the source.

Remarks

Disabled	Setting QueryPartitionMode to Disabled results in an attempt to partition the queries.
Adaptive	Setting QueryPartitionMode to Adaptive results in an attempt to partition the queries but reverts to its default behavior if the query does not support partitioning.
Enabled	Setting QueryPartitionMode to Enabled partitions the queries but throws an error if the queries do not support partitioning.

This option passes the query to the Google Spanner server as is.

Remarks

When this is set, queries are passed through directly to Google Spanner.

The value in seconds until the timeout error is thrown, canceling the operation.

Remarks

If Timeout = 0, operations do not time out. The operations run until they complete successfully or until they encounter an error condition.

If Timeout expires and the operation is not yet complete, the Sync App throws an exception.

A filepath pointing to the JSON configuration file containing your custom views.

Remarks

User Defined Views are defined in a JSON-formatted configuration file called UserDefinedViews.json. The Sync App automatically detects the views specified in this file.

You can also have multiple view definitions and control them using the UserDefinedViews connection property. When you use this property, only the specified views are seen by the Sync App.

This User Defined View configuration file is formatted as follows:

• Each root element defines the name of a view.
• Each root element contains a child element, called query, which contains the custom SQL query for the view.

For example:

{
	"MyView": {
		"query": "SELECT * FROM [CData].[GoogleSpanner].Customer WHERE MyColumn = 'value'"
	},
	"MyView2": {
		"query": "SELECT * FROM MyTable WHERE Id IN (1,2,3)"
	}
}

Use the UserDefinedViews connection property to specify the location of your JSON configuration file. For example:

"UserDefinedViews", C:\Users\yourusername\Desktop\tmp\UserDefinedViews.json

Note that the specified path is not embedded in quotation marks.