How do I print the full value of a string variable in delve?

The ability to configure the length of printed strings was recently added to delve. To see the full list of configuration options, run config -list;

(dlv) config -list
aliases            map[]
substitute-path    []
max-string-len     <not defined>
max-array-values   <not defined>
show-location-expr false

The one we’re interested in here is called max-string-len, which you can see is currently <not defined>. To increase the length to e.g. 1000, run

(dlv) config max-string-len 1000

Now running print myString should print the whole string.