Replace {version} in launch args

[skral]

It makes sense to replace the {version} tokens in the app args as well. The docs state this behavior too.
And you can't replace the token inside the before_app_launch hook because only the cleaned version string is passed.

[robblau]

Hi there, we're getting this functionality going and had a question about the fallback logic if versions are configured by the arg is None. What is the workflow that ends up in that situation?

Feels like if we do that for args we should do it everywhere to be consistent.

[robblau]

Ok... seeing consistent behavior with _get_app_path. More news soon on this PR soon.

[kporangehat]

Rather than duplicating the code that does the version replacement logic, how about breaking that out to it's own method as well? Something like this (untested):

    def _apply_version_to_setting(self, raw_string, version=None):
        """
        Replace any version tokens  contained in the raw_string with the appropriate version value from 
        the app settings. 

        If version is None, then no version has been specified and we will return the first version 
        from the versions list in the settings. If no versions have been defined in the settings, then 
        we return the raw_string since there's no replacement to do.

        :param raw_string: the raw string potentially containing the version tokens (eg. {version}, 
                           {v0}, ...) we will be replacing. This string could represent a number of 
                           things including a path, an args string, etc. 
        :param version: version string to use for the token replacement. 
        :returns: string with version tokens replaced with their appropriate values
        """
        if version is None:
            # there are two reasons version could be None
            # 1. if versions have not been configured, the raw string is assumed valid
            # 2. if versions has been configured, but no specific version was requested, then we 
            #    expand with the first element in the versions list, and use it as the default
            versions = self.get_setting("versions")
            if versions:
               return self._translate_version_tokens(raw_string, versions[0])
            else:
               return raw_string
        else:
            return self._translate_version_tokens(raw_string, version)

    def _get_app_path(self, version=None):
        """ Return the platform specific app path, performing version substitution. """
        platform_name = {"linux2": "linux", "darwin": "mac", "win32": "windows"}[sys.platform]
        raw_app_path = self.get_setting("%s_path" % platform_name, "")

        return self._apply_version_to_setting(raw_app_path)

    def _get_app_args(self, version=None):
        """ Return the platform specific app path, performing version substitution. """
        platform_name = {"linux2": "linux", "darwin": "mac", "win32": "windows"}[sys.platform]
        raw_app_args = self.get_setting("%s_args" % platform_name, "")

        return self._apply_version_to_setting(raw_app_args)

[kporangehat]

Sebastian,

I went ahead and made these changes in #30 and it's now in QA on our end. Thanks for the submission. Your approach was slightly different than my original idea and ultimately we liked yours better. Appreciate it! 🎉