Ban on!!!
Thanks a lot Felix for your clear explanation! Solved all my confusions.
Thanks!
On Mon, Sep 5, 2022 at 6:27 AM Felix Schumacher <
felix.schumac...@internetallee.de> wrote:
> Another important difference here (assuming this is groovy code in a
> jsr223 script), you are assigning Groovy variables, but __evalVar works on
> JMeter variables.
>
> To set a JMeter variable from within Groovy code, use vars.put("name",
> value).
>
> And to reiterate: Don't confuse ${...} from JMeter with the one from
> Groovy. JMeter will try to replace the ${...} stuff on first run (as Dmitri
> wrote).
>
> JMeter has a fallback mechanism, if it doesn't find a variable in its own
> namespace, that the expression will be used unchanged. In the case of a
> more complex expression, the result depends on the function.
>
> In your case:
>
> * ${query} (with no JMeter variable named "query") will result in
> ${query}, which is then interpreted by Groovy and accesses the Groovy
> variable "query".
>
> * The complex expression ${__evalVar(query)} will result in an empty
> string (as can be tested in the function helper dialog). (Groovy sees
> log.info('=='))
>
> Felix
> Am 05.09.22 um 09:05 schrieb Dmitri T:
>
> 1. You don't need to use __evalVar() function in Groovy, in general
> inlining JMeter Functions and Variables into scripts is not the best
> idea as only first occurrence will be cached
>
> <https://jmeter.apache.org/usermanual/component_reference.html#JSR223_Sampler>
> <https://jmeter.apache.org/usermanual/component_reference.html#JSR223_Sampler>
> so you will have the same query for all iterations even if the
> values will be changing.
> 2. If you want to utilize Groovy's string interpolation
> <https://groovy-lang.org/syntax.html#_string_interpolation>
> <https://groovy-lang.org/syntax.html#_string_interpolation> feature
> you need to use double quotation marks
> <https://groovy-lang.org/syntax.html#_double_quoted_string>
> <https://groovy-lang.org/syntax.html#_double_quoted_string> like
> "select ${column} from ${table}"
> 3. "column" and "table" variables need to be defined *before* declaring
> the "query" variable
>
>
> Suggested code change:
>
>
> column="name"
> table="customers"
> query="select ${column}from ${table}"
> log.info("${query}")
>
>
> More information on Groovy scripting in JMeter - Apache Groovy: What Is
> Groovy Used For? <https://www.blazemeter.com/blog/apache-groovy>
> <https://www.blazemeter.com/blog/apache-groovy>
>
>
> On 9/4/2022 10:31 PM, Tong Sun wrote:
>
> Hi,
>
> Fromhttps://jmeter.apache.org/usermanual/functions.html#__evalVar
>
> __evalVar
>
> The evalVar function returns the result of evaluating an expression stored
> in a variable.
>
> This allows one to read a string from a file, and process any variable
> references in it. For example, if the variable "query" contains "select
> ${column} from ${table}" and "column" and "table" contain "name" and "
> customers", then ${__evalVar(query)} will evaluate as "select name from
> customers".
>
> However, I tried it (in JM5.5), but wasn't able to make it work:
>
> query = '''select ${column} from ${table}'''
> column = "name"
> table = "customers"
>
> log.info("${query}")
> log.info('=${__evalVar(query)}=')
>
>
> but the output I got is:
>
> select ${column} from ${table}==
> How to make it work please?
>
>
