Check if template exists before download.

[sswaroopgupta]

If there is an error to initialize project. Error downloading file: https://downloads.gauge.org/templates/<plugin>.zip.
404 Not Found - Refer build logs https://build.getgauge.io/go/tab/build/detail/Csharp-FT/1293/specs/1/linux

Failed Step: Initialize a project named "Data_Driven_execution" without example spec
        Specification: specs/advanced_topics/data_driven_execution/scenario_with_unused_table_values/SpecWithDataTableValues.spec:6
        Error Message: java.lang.Exception: Unable to initialize gauge project.
        STDERR:



        STDOUT:

        Downloading csharp.zip
        Error ----------------------------------

        Failed to initialize project. Error downloading file: https://downloads.gauge.org/templates/csharp.zip.
        404 Not Found

        Get Support ----------------------------
        	Docs:          https://docs.gauge.org
        	Bugs:          https://github.com/getgauge/gauge/issues
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        Your Environment Information -----------
        	linux, 0.9.8, 503b4c7
        	csharp (0.10.3), html-report (4.0.4), java (0.6.7), xml-report (0.2.1)

        Stacktrace: 
        com.thoughtworks.gauge.test.common.builders.ProjectBuilder.build(ProjectBuilder.java:27)
        com.thoughtworks.gauge.test.implementation.ProjectInit.projectInitWithoutHelloWorldSpec(ProjectInit.java:42)

It should be initialized with the offline template

This is applicable only to the basic template
example - gauge init csharp

This is a master issue. This can be done for all language plugins.

[sriv]

There is no csharp template. so this isn't an optimization.

gauge init csharp should always use the language runner for template generation.

in any case, if the internet is unavailable, gauge should fall back to the runner.

Any hints on how to replicate this?

[sriv]

fix should be available in nightly >= 25/4/2018

gauge sends a HEAD request to check if requested template exists in the template repository, and on receiving a 404 it used to error out. Now gauge is a little more strict. only on explicitly receiving a 200 shall gauge attempt to download. This prevents false positives if the server sends a 5XX or 4XX response.