Log settings

Firely Server uses Serilog for logging. The logging settings are controlled in json configuration files called logsettings(.*).json. The files are read in a hierarchy, exactly like the appsettings files are. Firely Server comes with default settings in logsettings.default.json. You can adjust the way Firely Server logs its information by overriding these default settings in logsettings.json or logsettings.instance.json. You need to create this file yourself.

Alternatively you can control Log settings with Environment Variables.

Firely Server by default does nog log any Patient Health Information data, regardless of the level of the log. The only PHI part that can be included in the log is the User Name, when running with Smart authorization (so the user is identified) and including this part in the outputTemplate (see below).

Changing the log event level

Serilog defines several levels of log events. From low to high, these are Verbose, Debug, Information, Warning, Error and Fatal. You can set the minimum level you want to log, meaning that events for that level or higher will be logged. By default, Firely Server uses Error as the minimum level of recording information.

To change the level of logging, follow these steps:

Find this setting:

"MinimumLevel": {
        "Default": "Error",
},

Change the setting for Default from Error to the level you need, from the choice of Verbose, Debug, Information, Warning, Error and Fatal.

You can deviate from the default minimum level for specific namespaces. You do this by specifying the namespace and the log event level you would like for this namespace, for example:

"MinimumLevel": {
        "Default": "Error",
        "Override": {
                "Vonk": "Warning"
        }
},

Some additional namespaces you might want to log are:

Vonk.Configuration to log configuration information on startup
Vonk.Core.Licensing to show license information in your logs
Vonk.Repository.Sql.Raw to log SQL repository events for Firely Server v4.3.0 and above
Vonk.Repository.Sql to log SQL repository events for Firely Server v4.2.0 and below
Vonk.Repository.Document.Db to log MongoDB repository events
Vonk.Repository.Memory to log memory database repository events
Vonk.Core.Repository.EntryIndexerContext, set it to "Error" if you have excessive warnings about indexing (mostly when importing Synthea <https://synthea.mitre.org/downloads> data)
Microsoft to log events from the Microsoft libraries
Microsoft.AspNetCore.Diagnostics to report request handling times
Microsoft.AspNetCore.Hosting.Diagnostics to log individual requests
System to log events from the System libraries

Please note that the namespaces are evaluated in order from top to bottom, so more generic ‘catch all’ namespaces should be at the bottom of the list. So this will log events on Vonk.Repository.Sql.Raw on Information level:

"MinimumLevel": {
        "Default": "Error",
        "Override": {
                "Vonk.Repository.Sql.Raw": "Information",
                "Vonk": "Warning"
        }
},

But in this (purposefully incorrect) example the Warning level on the Vonk namespace will override the Information level on the Vonk.Repository.Sql.Raw namespace:

"MinimumLevel": {
        "Default": "Error",
        "Override": {
                "Vonk": "Warning",
                "Vonk.Repository.Sql.Raw": "Information"
        }
},

Logging individual requests

If you want to log individual requests, you can do so by adjusting the “Override” section to include Microsoft.AspNetCore.Hosting.Diagnostics:

"MinimumLevel": {
        "Default": "Error",
        "Override": {
                "Microsoft.AspNetCore.Hosting.Diagnostics": "Information"
        }
},

Here is an example of the logs when you post a Patient resource with these logsettings:

2023-08-09 10:25:55.028 +02:00 [UserId: ] [Username: ] [Information] [ReqId: 0HMSOM901IS1A:00000002] Request starting HTTP/1.1 POST http://localhost:4080/Patient application/fhir+json 164
2023-08-09 10:25:57.225 +02:00 [UserId: ] [Username: ] [Information] [ReqId: 0HMSOM901IS1A:00000002] Request finished HTTP/1.1 POST http://localhost:4080/Patient application/fhir+json 164 - 201 340 application/fhir+json;+fhirVersion=4.0;+charset=utf-8 2199.2748ms

The first log line includes on the request that was made, the second line contains information on the response of Firely Server. As you can see, the logs include information on the request type, any headers that are included, and the time it took to make this request.

Changing the sink

Another setting you can adjust is WriteTo. This tells Serilog which sink(s) to log to. Serilog provides several sinks, and for Firely Server you can use Console, File, ApplicationInsights and Seq. All of which can be wrapped in an Async sink to avoid blocking Firely Server when waiting for the sink to process the log statements.

Console

The Console sink will write to your shell.

Find the WriteTo setting:

"WriteTo": [
        {
                "Name": "Async",
                "Args": {
                        "configure": [
                                {
                                "Name": "Console",
                                "Args": {
                                        "restrictedToMinimumLevel": "Information",
                                        "outputTemplate": "{Timestamp:yyyy-MM-dd HH:mm:ss.fff zzz} {UserId} {Username} [{Level}] [ReqId: {RequestId}] {Message}{NewLine}{Exception}"
                                }
                                }
                        ]
                }
        },
        {
                //Settings for other sinks
        }

The Console is notoriously slow at processing log statements, so it is recommended to limit the number of statements for this sink. Use the restrictedToMinimumLevel to do so. Also, if you are on Windows, the Powershell command window appears to be faster than the traditional Command Line window.

Settings for the Console sink:

outputTemplate: What information will be in each log line. Besides regular text you can use placeholders for information from the log statement:

{Timestamp:yyyy-MM-dd HH:mm:ss.fff zzz}: When this was logged, with formatting

{UserId}: Technical id of the logged in user - if applicable

{Username}: Name of the logged in user - if applicable

{Application}: Name of the application (in case other applications are logging to the same sink). Is set to Vonk at the bottom of the logsettings file

{Level}: Level of the log, see the values in Changing the log event level

{MachineName}: Name of the machine hosting the Firely Server instance. Especially useful when running multiple instances all logging to the same file.

{RequestId}: Unique id of the web request, useful to correlate log statements

{Message}}: Actual message being logged

{Exception}: If an error is logged, Firely Server may include the original exception. That is then formatted here.

{SourceContext}: The class from which the log statement originated (this is usually not needed by end users).

{NewLine}: Well, ehh, continue on the next line,

{CorrelationId}: In case you want to follow requests across multiple containers, you can set the CorrelationId to be included in the logs. See below.

restrictedToMinimumLevel: Only log messages from this level up are sent to this sink.

File

The File sink will write to a file, possibly rolling it by interval or size.

Find the WriteTo setting:

"WriteTo": [
        {
        {
                //Settings for Console
        }
        },
        {
        "Name": "Async",
        "Args": {
                "configure": [
                        {
                        "Name": "File",
                        "Args": {
                                "path": "%temp%/vonk.log",
                                "rollingInterval": "Day",
                                "fileSizeLimitBytes": "",
                                "retainedFileCountLimit": "7",
                                "outputTemplate": "{Timestamp:yyyy-MM-dd HH:mm:ss.fff zzz} {UserId} {Username} [{Application}] [{Level}] [Machine: {MachineName}] [ReqId: {RequestId}] {Message}{NewLine}{Exception}",
                                "restrictedToMinimumLevel": "Verbose"
                        }
                        }
                ]
        }
        },
        {
                //Settings for Azure ApplicationInsights
        }

Under File, change the location of the logfiles by editing the value for path. For example:
```
{
        "Name": "RollingFile",
        "Args": {
                "path": "c:/logfiles/vonk.log"
        }
},
```
Other values that you can set for the File log are:
- rollingInterval: When this interval expires, the log system will start a new file. The start datetime of each interval is added to the filename. Valid values are Infinite, Year, Month, Day, Hour, Minute.
- fileSizeLimitBytes: Limit the size of the log file, which is 1GB by default. When it is full, the log system will start a new file.
- retainedFileCountLimit: If more than this number of log files is written, the oldest will be deleted. Default value is 31. Explicitly setting it to an empty value means files are never deleted.
- outputTemplate: as described for Console.
- restrictedToMinimumLevel: as described for Console.

Application Insights

Firely Server can also log to Azure Application Insights (“Application Insights Telemetry”). What you need to do:

Create an Application Insights instance on Azure.
Get the ConnectionString from the Properties blade of this instance.

Add the correct sink to the logsettings.json:

"WriteTo": [
        {
                "Name": "ApplicationInsights",
                "Args": {
                        "connectionString": "[your connection string here]",
                        "telemetryConverter": "Serilog.Sinks.ApplicationInsights.TelemetryConverters.TraceTelemetryConverter, Serilog.Sinks.ApplicationInsights"
                        "restrictedToMinimumLevel": "Verbose" //Or a higher level
                }
        },
],

This also enables Dependency Tracking for access to your database. This works for both SQL Server and MongoDB. And for the log sent to Seq if you enabled that.
If you set the level for Application Insights to Verbose, and combine that with Database details, you get all the database commands right into Application Insights.

Seq

Seq is a web interface to easily inspect structured logs.

For the Seq sink, you can also specify arguments. One of them is the server URL for your Seq server:

"WriteTo": [
        {
                "Name": "Seq",
                "Args": { "serverUrl": "http://localhost:5341" }
        }

Change serverUrl to the URL of your Seq server
restrictedToMinimumLevel: as described for Console.

Elasticsearch

Elasticsearch is a search engine based on the Lucene library. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents.

For the Elasticsearch sink, you can also specify arguments. One of them is the nodeUris for your Elasticsearch server:

"WriteTo": [
        {
                "Name": "Elasticsearch",
                "Args": {
                        "nodeUris": "http://localhost:9200",
                        "connectionGlobalHeaders": "Authorization=..."
                }
        }

Change nodeUris to the URL of your Elasticsearch node
Change connectionGlobalHeaders: if you need to add headers to the request. For example, if you need to authenticate to your Elasticsearch server, you can add the Authorization header here.
restrictedToMinimumLevel: as described for Console.
More details can be found in sinks Github repo and Elasticsearch docs.

MongoDb

Firely Server can also log to MongoDb.

Add the correct sink to the logsettings.json:

"WriteTo": [
        {
                "Name": "MongoDBBson",
                "Args": {
                "databaseUrl": "mongodb://username:password@localhost:27017/<db name>",
                "collectionName": "vonklogs",
                "cappedMaxSizeMb": "1024",
                "cappedMaxDocuments": "50000",
                "rollingInterval": "Month"
                }
        }

Change databaseUrl to match your MongoDb server.
Change collection name where you want to store logs
restrictedToMinimumLevel: as described for Console.

AWS Cloudwatch

Firely Server can also log to AWS Cloudwatch. What you need to do:

Create a user with restricted privilages in AWS that can write to Cloudwatch
Configure the machine with the Firely Server instance with the credentials of this AWS account
These 2 steps are described here

Add the correct sink to the logsettings.json:

"WriteTo": [
        {
                "Name": "AmazonCloudWatch",
                "Args": {
                        "logGroup": "<the name of your log group>",
                        "logStreamPrefix": "<the description to prefix your log stream>",
                        "restrictedToMinimumLevel": "Verbose" //Or a higher level
                }
        },
],

Splunk

Firely Server can also log to Splunk. What you need to do:

Setup a Splunk environment as described by the Splunk documentation
Create a HTTP Event Collector for the application, save the Token Value for later use
Check in the Global Settings in the HTTP Event Collector screen which port is used

Add the correct sink to the logsettings.json:

    "WriteTo": [
            {
    "Name": "EventCollector",
    "Args": {
        "splunkHost": "<splunk endpoint>", // e.g. https://splunk:8088
        "eventCollectorToken": "<token value>"
    }
}
    ],

Database details

Whether you use MongoDB or SQL Server, you can have Firely Server log in detail what happens towards your database. Just set the appropriate loglevel to ‘Verbose’:

"MinimumLevel": {
        "Default": "Error",
        "Override": {
                "Vonk.Repository": "Verbose"
        }
},

You can also control the logsettings for the different repositories more finely granulated:

"MinimumLevel": {
        "Default": "Error",
        "Override": {
                // (for versions before FS 4.6.0)
                "Vonk.Repository.Sql": "Verbose",
                // OR (for FS 4.6.0 or later AND if Sql.Raw is enabled)
                "Vonk.Repository.Sql.Raw": "Verbose",
                // OR (for MongoDb)
                "Vonk.Repository.Document.Db": "Verbose",
                // OR (for SQLite)
                "Vonk.Repository": "Verbose",
                "Microsoft.EntityFrameworkCore": "Verbose"
        }
},

Remember to adjust your sink settings so that "restrictedToMinimumLevel": "Verbose" is set. If you do so you probably don’t want all this detail in your console sink, so you can limit the level for that, see Console above.

SQL query parameter logging

It might be useful to log SQL queries that Firely Server executes against your database. You can get even more insights into what is happening when SQL query parameter values also get logged. However, this cannot be enabled by default due to data privacy concerns.

You can enable SQL query parameter values logging by setting the LogSqlQueryParameterValues to true for the corresponding database in your appsettings.instance.json. Example:

{
        "Administration": {
                "SqlDbOptions": {
                        "ConnectionString": "<connection string>",
                        "LogSqlQueryParameterValues": true // Add this line to your config file to log SQL query param values for your SQL Server Administration database
                }
        },
        // OR:
        {
                "SQLiteDbOptions": {
                        "ConnectionString": "<connection string>",
                        "LogSqlQueryParameterValues": true // Add this line to your config file to log SQL query param values for your Sqlite Data database
                }
        }
}

Setting CorrelationId for tracing requests across multiple services

Firely Server can log a RequestId to identify individual requests, but this is an auto-generated GUID and cannot be adjusted. This is tricky if you want to log requests across multiple services/containers, how to recognize a particular request from EHR to Firely Server if the RequestId is set automatically? As an answer to this, it is possible to set a CorrelationId for requests. The CorrelationId can be set manually by adding a header to the request that needs to be traced. Note that you can give any name to this header, as long as it matches the headerKey in the “Enrich” section of your logsettings. This section needs to be adjusted to include the WithCorrelationIdHeader setting:

"Enrich": [
        "FromLogContext",
        "WithMachineName",
        {
        "Name": "WithCorrelationIdHeader",
        "Args": {
                "headerKey": "custom-correlation-id"
                }
        }
],

Be sure to add [CorrId: {CorrelationId}] to your “outputTemplate” settings to view the CorrelationId in the logs. Below is an example of the resulting loglines when the custom-correlation-id header is set to “My custom correlation Id”:

2023-08-09 11:22:15.901 +02:00 [UserId: ] [Username: ] [Information] [ReqId: 0HMSON8FK36UF:00000002] [CorrId: My custom correlation Id] Request starting HTTP/1.1 GET http://localhost:4080/Patient - -
2023-08-09 11:22:17.884 +02:00 [UserId: ] [Username: ] [Information] [ReqId: 0HMSON8FK36UF:00000002] [CorrId: My custom correlation Id] Request finished HTTP/1.1 GET http://localhost:4080/Patient - - - 200 6642 application/fhir+json;+fhirVersion=4.0;+charset=utf-8 1986.1211ms

Note that if this header is not included in the request, Firely Server will automatically assign a GUID to CorrelationId.