Settings

Philter has settings to control how it operates. The settings and how to configure each are described below.

Configuring Philter

The Philter Settings File

Philter’s settings file is application.properties. This file is located in Philter’s installation directory, which is most likely /opt/philter. All changes to this files requires Philter to be restarted for the changes to take affect. To restart Philter execute the following commands:

sudo systemctl restart philter.service
sudo systemctl restart philter-ner.service

Using Environment Variables

Properties set via environment variables take precedence over properties set in Philter's settings file.

All following properties can also be set as environment variables by prepending PHILTER_ to the property name and changing periods to underscores. For example, the property filter.profiles.directory can be set using the environment variable PHILTER_FILTER_PROFILES_DIRECTORY by:

export PHILTER_FILTER_PROFILES_DIRECTORY=/profiles/

Setting or changing an environment variable requires Philter to be restarted. To restart Philter execute the following commands:

sudo systemctl restart philter.service
sudo systemctl restart philter-ner.service

Policies

Setting	Description	Allowed Values	Default Value
`filter.policies.directory`	The directory in which to look for policies.	Any valid directory path.	`./policies/`

Span Disambiguation

These values configure Philter's span disambiguation feature to determine the most appropriate type of sensitive information when duplicate spans are identified. In a deployment of multiple Philter instances, you must enable the cache service for span disambiguation to work as expected.

	Description	Allowed Values	Default Value
`span.disambiguation.enabled`	Whether or not to enable span disambiguation.	`true`, `false`	`false`

Metrics

These values configure how Philter reports metrics during its operations. For more information on the metrics collected and reported see Metrics. Philter can report metrics via JMX, Prometheus, Datadog, and Amazon CloudWatch. You may enable any combination of metrics services, or none of them to disable metrics reporting.

Setting	Description	Allowed Values	Default Value
`metrics.prefix`	A value used to prefix metric names.	Any value	`philter`
`metrics.hostname`	A means for differentiating metrics across multiple instances of Philter.	Any value	None

JMX Metric Reporting

Setting	Description	Allowed Values	Default Value
`metrics.jmx.enabled`	Enables metrics reporting via JMX.	`true`, `false`	`false`

Prometheus Metric Reporting

Metrics will be published to an HTTP endpoint when enabled. By default, the metrics endpoint is http://philter-ip:9100/metrics. This path can be modified via the settings listed below.

Setting	Description	Allowed Values	Default Value
`metrics.prometheus.enabled`	Enables metrics reporting via an HTTP endpoint.	`true`, `false`	`false`
`metrics.prometheus.port`	The port on which the metrics HTTP server listens.	Any valid port number.	`9100`
`metrics.prometheus.metrics`	The context at which the metrics HTTP server listens.	Any valid HTTP context.	`metrics`

Datadog Metric Reporting

Metrics will be published to Datadog when enabled.

Setting	Description	Allowed Values	Default Value
`metrics.datadog.enabled`	Enables metrics reporting via Datadog.	`true`, `false`	`false`
`metrics.datadog.apikey`	Your Datadog API key.	Any valid Datadog API key.	None

Amazon CloudWatch Metric Reporting

Metrics will be published to CloudWatch when enabled. The value of metrics.hostname will be used as a dimension for the metrics.

Setting	Description	Allowed Values	Default Value
`metrics.cloudwatch.enabled`	Enables metrics reporting via AWS CloudWatch.	`true`, `false`	`false`
`metrics.cloudwatch.region`	The AWS CloudWatch region.	Any valid AWS region name.	`us-east-1`
`metrics.cloudwatch.namespace`	The AWS CloudWatch namespace for the metrics.	Any valid CloudWatch Metrics namespace name.	None

AWS CloudWatch Credentials

Philter will look for AWS credentials following the default AWS credentials chain (environment variables, default credentials file, instance profile credentials). When running in AWS using an instance profile via an IAM role is the preferred method. When not possible, using environment variables is recommended and can be set as shown below:

export AWS_ACCESS_KEY_ID="your-access-key"
export AWS_SECRET_ACCESS_KEY="your-secret-key"

AWS IAM Role

The IAM user or role being used must have PutMetricData permissions. An example policy is shown below.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor0",
            "Effect": "Allow",
            "Action": [
                "cloudwatch:PutMetricData"
            ],
            "Resource": "*"
        }
    ]
}

SSL/TLS

By default, Philter is pre-configured for two-way SSL/TLS connections to both Philter's API and Philter's UI. However, client certificates are "wanted" but not "required." This can be changed to require client certificates in Philter's settings (described below under Two-Way SSL/TLS).

One-Way SSL/TLS

In one-way SSL/TLS, Philter's API is configured to accept connections only over SSL/TLS. This can help prevent a man-in-the-middle attack.

When Philter is deployed via the AWS Marketplace, Microsoft Azure Marketplace, or Google Cloud Marketplace, one-way SSL/TLS will be enabled by default with a self-signed certificate. It is recommended you replace this self-signed certificate with a valid certificate for your organization. When configured, the SSL/TLS listener will be available on the port defined by server.port, which is 8080 by default.

To enable Philter's SSL/TLS listener, provide the following properties:

Setting	Description	Allowed Values	Default Value
`server.ssl.key-store-type`	The type of keystore.	`PKCS12` or `JKS`	None
`server.ssl.key-store`	Full path to the keystore file.	File path.	None
`server.ssl.key-store-password`	The keystore’s password.	A valid password.	None
`server.ssl.key-alias`	The certificate alias in the keystore.	A valid alias.	None

An example configuration to enable SSL is shown below:

# SSL certificate settings
security.require-ssl=true
server.ssl.key-store-type=PKCS12
server.ssl.key-store=/opt/philter/ssl/philter.p12
server.ssl.key-store-password=Password123!
server.ssl.key-alias=philter
server.ssl.client-auth=none

The command that generated the self-signed certificate referenced by the above configuration is:

keytool -genkeypair -keypass Password123! -dname "CN=philter, O=philter, C=US\ -alias philter -keyalg RSA -keysize 4096 -storepass Password123! -storetype PKCS12 -keystore /opt/philter/ssl/philter.p12 -validity 3650

Two-Way SSL/TLS

In two-way SSL/TLS connections, both the client and the server verify each other's identity. A certificate authority (CA) generates a server certificate and a client certificate along with the corresponding private keys.

To configure Philter to use two-way SSL/TLS, set the configuration to set server.ssl.client-auth to need and to specify the location of the trust store and the trust store password. (Please contact us for assistance with creating self-signed certificates.)

# SSL certificate settings
security.require-ssl=true
server.ssl.key-store-type=PKCS12
server.ssl.key-store=/opt/philter/ssl/philter.p12
server.ssl.key-store-password=Password123!
server.ssl.key-alias=philter
server.ssl.client-auth=need
server.ssl.trust-store=/path/to/truststure.jks
server.ssl.trust-store-password=changeit

All clients of the Philter API must now present a valid certificate signed by the same CA as the server certificate to be granted access to Philter's API.

In the example curl command below to filter text, we are providing the client certificate and the client private key in the API request.

curl -vvvv -k --cert client.crt --key client.key -H "Content-type: text/plain" "https://localhost:8080/api/filter" --data "George Washington was president and his ssn was 123-45-6789."

Cache Service

The cache service is required to use consistent anonymization and policies stored in Amazon S3. Philter supports Redis as the backend cache. When Redis is not used, an in-memory cache is used instead. The in-memory cache is not recommended because all contents will be stored in memory on the local Philter instance.

The cache will contain sensitive information. It is important that you take the necessary precautions to secure the cache itself and all communication between Philter and the cache.

Setting	Description	Allowed Values	Default Value
`cache.redis.enabled`	Whether or not to use Redis as the cache.	`true`, `false`	`false`
`cache.redis.host`	The hostname or IP address of the Redis cache.	Any valid Redis endpoint.	None
`cache.redis.port`	The Redis cache port.	Any valid port.	`6379`
`cache.redis.auth.token`	The Redis auth token.	Any valid token.	None
`cache.redis.ssl`	Whether or not to use SSL for communication with the Redis cache.	`true`, `false`	`false`

The following Redis settings are only required when using a self-signed SSL certificate.

Setting	Description	Allowed Values	Default Value
`cache.redis.truststore`	The path to the trust store.	Any valid file path.	None
`cache.redis.truststore.password`	The trust store password.	Any valid file path.	None
`cache.redis.keystore`	The path to the keystore.	Any valid file path.	None
`cache.redis.keystore.password`	The keystore password.	Any valid file path.	None

Advanced Settings

Setting	Description	Allowed Values	Default Value
`ner.timeout.sec`	Controls the timeout in seconds when performing name entity recognition. Longer text may require longer processing times.	An integer value	`600`
`ner.max.idle.connections`	The maximum number of idle connections to maintain for the named entity recognition. More connections may improve performance in some cases.	An integer value.	`30`
`ner.keep.alive.duration.ms`	The amount of time in milliseconds to keep named entity recognition connections alive. Longer text may require longer processing times.	An integer value.	`60`

Last modified: 08 November 2023