Configuring trace on the web server plug-in

By configuring tracing, you can define what trace information to gather from your environment.

About this task

Configure tracing on your web server to collect specific log levels from your environment. The logs are recorded in the standard plug-in log file plugins_root/logs/web_server_name/http_plugin.log. For more information about plug-in logging, read about web server plug-in properties.

There are two types of processing in the plug-in: request processing and control processing. Request processing consists of any logic that is required to process an HTTP request, or the HTTP response from the origin server. Control processing is any processing that does not fall into the request processing category. For example, all communication with the REST service to discover routing information is considered control processing.

For trace setting, the following precedence hierarchy applies:

Default trace hierarchy
1. If the default trace specification is set, the control trace specification is used.
2. If no default trace specification is set, the NOTICE trace level is used.
Request trace hierarchy
1. If a rule matches a request, the trace specification of this rule is used.
2. If the rule does not match the request, and the DefaultRequestTraceSpec property is set, the trace specification in DefaultRequestTraceSpec property is used.
3. If the rule does not match the request, the DefaultRequestTraceSpec property is not set, but the control trace specification is set, then the control trace specification is used.
4. If none of these specifications are set, the NOTICE trace level is used.

Use the subexpression builder to build complex rule conditions from subexpression by using AND, OR, NOT, and parenthetical grouping. The rule builder validates the rule when you apply the changes, and alerts you to mismatched parentheses, and unsupported logic operators.

The operand is part of the classification rule that the run time uses to match a rule to a job. For instance, if you specify a protocol type equal to HTTP, the runtime searches for a job that has a protocol type of HTTP. The following list includes operand choices:

Table 1. HTTP request operands
Operand	Syntax	Description
Virtual host	`virtualhost`	Virtual host target of the request, which is used for configuring web applications to a particular host name.
Virtual port	`numeric`	Virtual port target of the request, which is used for configuring web applications to a particular port.
URI	`uri`	Uniform Resource Identifier Helps you identify the path of the request: if the URL is http://host:port/path?p1=v1, the path is `path`.
User ID	`userid`	Returns the user ID for the authenticated user who sent the request.
Group ID	`groupingid`	Returns a list of group names for the authenticated user who sent the request.
Request query parameter name	`queryparm$<name>`	A header name and value. For example, the expression `queryparm$timezone='EST'` tests a request to see whether the request contains an HTTP query parameter named `timezone` with a value of `EST`. To test for presence or absence of a query parameter, use one of the following forms: `queryparm$timezone IS NOT NULL queryparm$timezone IS NULL`
Request header name	`header$<name>`	A header name and value. For example, the expression `header$Host='localhost'` tests a request to see whether it contains an HTTP host header with a value of `localhost`. To test for presence or absence of the host header, use one of the following expressions: `header$Host IS NOT NULL header$Host IS NULL`
Cookie header name	`cookie$<name>`	A cookie name. For example, the expression `cookie$My_Cookie_Name='My_Cookie_Value'` tests a request to see whether it contains a cookie named `My_Cookie_Name` with a value of `My_Cookie_Value`. To test for the presence or absence of a particular cookie, use one of the following expressions: `cookie$MyCookieName IS NOT NULL cookie$MyCookieName IS NULL`
HTTP method	`HTTPMethod`	The HTTP method for the request. Possible values are POST, GET, PUT, and DELETE.
Client host	`clienthost`	The fully qualified client host name. This value is the Internet Protocol (IP) command host name. This operand does not support numeric operators such as `>, >=, <, <=`.
Client IPV4	`clientipv4`	The IP address of the client using the Internet Protocol version 4 (IPv4) dotted quad address type `n.n.n.n`.
Client IPV6	`clientipv6`	The Internet Protocol version 6 (IPv6) 128-bit address type of `x:x:x:x:x:x:x:x` following Request for Comments 1924 (RFC 1924) of the client computer.
Server host	`serverhost`	The fully qualified host name of the server. This operand does not support numeric operators such as `>, >=, <, <=`.
Server IPV4	`serveripv4`	The IP address of the server computer using the IPv4 dotted quad address type `n.n.n.n`.
Server IPV6	`serveripv6`	The IPv6 128-bit address type of `x:x:x:x:x:x:x:x` following RFC 1924 of the server computer.
Port	`port`	The listening port on which the request was received.
Protocol	`protocol`	The communications protocol that transmits the request. Currently supported protocols are HTTP, HTTPS, SOAP, and SOAPS.
Time	`time`	Used to define the date and time of day that a specific request must be honored. Two optional fields are `StartTime` and `EndTime`. If a request is received outside of the defined window, the request is not processed. The Start Time and End Time fields each have the following format: `dayOfWeek/dayOfMonth/month/year::hour:minute:second`. For example, Thursday, the 11th of April, year 2007 at 1:03:45 PM is specified as: Thu/11/Apr/2007::13:03:45 Any field can use a wildcard with the value . For example, the first of each month is specified as `/1`. The `dayofWeek` values are Sun, Mon, Tue, Wed, Thu, Fri, Sat, and the `dayOfMonth` values range1-31. The `month` value is a non-numeric value that represents the 12 months: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec. The `year` value is composed of the year's 4 digits. For example, 2007. The `hour` value is the hour of day in the 24-hour clock. For example, 8am is represented as::8. The `minute` and `second` are integers that range 0-59. The forward slash (/) is used to separate date parameters, the double colon (::) is used to separate the date parameters, and the colon (:) is used to separate the time of day parameters. The Boolean result of the entire rule in which the `time` operand is used determines the routing action taken.
Percentage	`percentage$<val>`	The percentage operand evaluates to `true`, a fixed percentage of the time. For example, `percentage$50` evaluates to `true` on average 50% of the time.
Ramp up	`rampup$<startTime>$<completionTime>`	The `rampup` operand evaluates to `true` a variable percentage of the time. It always evaluates to `false` before `<startTime>` and to `true` after `<completionTime>`. As time progresses from `<startTime>` to `<completionTime>`, it evaluates to `true`, a linearly increasing percentage. The format of `<startTime>` and `<completionTime>` is `day/month/year::hour:min:sec`. where `day` is the day of the month, `month` is one of the 12 months: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec, `year` is the four digit year, `hour` is the two digit hour of the 24 hour clock, `min` is the two digit value for minute, and `sec` is the two digit value for minute. For example, rampup$01/Jan/2007::08:00:00$01/Jan/2007::17:00:00 begins to occasionally evaluate to `true` at 8 AM on Jan 1, 2007 and always evaluates to `true` by ramp up completion time at 5 PM of the same day.

Depending on the operator that you choose, enter a value for the subexpression that you want to create. All operators evaluate to boolean values. Operators are not case-sensitive: AND is equivalent to AnD.

Table 2. Trace specification operators
Operator	Description
Equals Ignore Case (EQUALSIGNORECASE)	Equals ignore case operator. The case of the strings is ignored. `'ABC' EQUALSIGNORECASE 'abc'` is true. `('ABC' = 'abc')` is false.
Not Equals (< >)	The not equal operator expresses that the operand value is not equal to the value you enter.
In (IN)	For `string IN list of strings` evaluates to true if the first string exactly matches (case sensitive) the second string. For example: `'adrian' in ('keith','eric','kalyan','david', 'adrian and etc')` is false. `'adrian' in ('tom','adrian')` is true. `'adrian' in ('Tom','Adrian')`is false. `integer IN list of integers`: `1 in (1,2,3,4,5)` is true. `6 in (1,2,3,4,5)` is false.
Like (LIKE)	Expresses pattern matching for string operand values. The value must contain the wildcard character (`%`) in the position where the pattern matching is expected to start. For example, the expression: `host LIKE %blanca` matches the word `blanca` and any other word that ends in `blanca`, while the expression: `host LIKE blanca%` matches the word `blanca` and any other word that starts with `blanca`. The expression: `host LIKE %blanca%` matches the word `blanca` and any word that has the token `blanca` embedded in it.
Like Ignore Case (LIKEIGNORECASE)	This operator expresses pattern matching for string operand values. The case of the strings is ignored.
Is Not Null (IS NOT NULL)	A validation of the query shows that the requested parameter exists.
Concatenate (+)	This operator evaluates `'abc'+'def'` to `'abcdef'`.
Like In (LIKEIN)	This operator expresses `string likein (string1, string2, string3,...)` evaluates to true if the string preceding `likein` matches one or more of the strings (`stringN`).
Is Null (IS NULL)	A validation of the query shows that the requested parameter does not exist. Tests for an operand that has a `NULL` value.
Equals ( = )	The equality operator expresses a match in case-sensitive match.
Greater Than (>)	Evaluates to the standard logical result.
Greater Than or Equals (>=)	Evaluates to the standard logical result.
Less Than (<)	Evaluates to the standard logical result.
Less Than or Equals (<=)	Evaluates to the standard logical result.
Between (BETWEEN)	Used with `AND` to select a range of values inclusive of the first (low) value and the last (high) value. Together, they operate on numbers and dates values.

Procedure

To select your trace specification and log detail level, follow this procedure:
1. Select your trace specification and log detail level.
  In the administrative console, click Servers > Server types > Web servers > web_server_name > Intelligent Management > Trace specification and expand the trace specification tree. Click a trace specification to select one of the following log levels:
  - EMERG
  - ALERT
  - CRITICAL
  - ERROR
  - WARNING
  - NOTICE
  - INFO
  - DEBUG
  - OFF
  In the specified log sequence, if you select a log level, you enable trace for all preceding log levels. If you do not configure your trace specification, NOTICE logs are recorded by default. You can select multiple specifications. Your selected settings and levels display in the trace window. Multiple specifications are separated by a comma:
```
control:INFO, control.stateChange:DEBUG
```
  In this example, INFO logs are recorded for the control specification. DEBUG logs are recorded for the specification sequence: control.stateChange.
2. Click Apply, and the runtime trace on your web server is configured based on your selection.
  In the specified log sequence, if you select a log level, you enable trace for all preceding log levels. If you do not configure your trace specification, NOTICE logs are recorded by default. You can select multiple specifications. Your selected settings and levels display in the trace window. Multiple specifications are separated by a comma:
```
control:INFO, control.stateChange:DEBUG
```
  In this example, INFO logs are recorded for the control specification. DEBUG logs are recorded for the specification sequence: control.stateChange.
To enter a trace specification rule, follow this procedure:
1. Define the trace rule.
  In the administrative console, click Servers > Server types > Web servers > web_server_name > Intelligent Management > Trace specification. Enter the trace condition in the Edit condition field, or use the Subexpression builder to generate a new expression. Click Syntax help for more information about the trace condition syntax.
2. Click Apply.
  The runtime trace on your web server is now configured based on your new request trace condition.
To select your request trace specification and log detail level, follow this procedure:
1. Select your request trace specification and log detail level.
  In the administrative console, click Servers > Server types > Web servers > web_server_name > Intelligent Management > Trace specification and expand the request trace specification tree. Click a conditional trace specification to select one of the following log levels:
  - EMERG
  - ALERT
  - CRITICAL
  - ERROR
  - WARNING
  - NOTICE
  - INFO
  - DEBUG
  - OFF
2. Click Apply, and the runtime trace on your web server is configured based on your selection.
  In the specified log sequence, if you select a log level, you enable trace for all preceding log levels. If you do not configure your trace specification, NOTICE logs are recorded by default. You can select multiple specifications. Your selected settings and levels display in the trace window. Multiple specifications are separated by a comma. Example:
```
http:INFO, http.request.select.affinity.break:DEBUG
```
  In this example, INFO logs are recorded for the http specification. DEBUG logs are recorded for the specification sequence: http.request.select.affinity.break

Results

You configured tracing on your web server plug-in.