Running cloud trace with webpack

[smousa]

When I try to start my nodejs service with trace, I see the following error:
ERROR:@google-cloud/trace-agent: TraceAgent#start: Tracing might not work as the following modules were loaded before the trace agent was initialized: [...]
and it lists every package dependency in my package.json.

I placed the declaration at the top of index.js:
require('@google-cloud/trace-agent').start({projectId: 'projectId'})

Which is where my webpack config js points to:

 module.exports = merge(baseWebpackConfig, {
    mode: "development",
    entry: ['webpack/hot/poll?500', './server/index'],
    ....
})

Do you know if I am doing something wrong?

[kjin]

We currently do not support webpack, since we assume that required modules reside in node_modules. I will look into whether we can support this -- but I'm not sure if it's possible.

[ofrobots]

@smousa can you include some details on your motivation to use webpack on a server side project? As @kjin said, this is a use-case we have not considered up till now. We would like to understand why/how this is being used to figure what solutions might be possible.

[smousa]

Thanks for the reply. What I have been using webpack was primarily for hot module reloading. But I think I found a workaround for my immediate issue, which is to initialize tracing in a separate file, like trace.js, require the index and have webpack load trace.js first:

trace.js:

require('@google-cloud/trace-agent').start({samplingRate:0})                                                                                                                                                       
require('./index')

webpack.*.conf.js

module.exports = merge(baseWebpackConfig, {                                     
    mode: "development",                                                        
    entry: ['webpack/hot/poll?500', './server/trace'],                          
    watch: true,                                                                
    externals: [nodeExternals({whitelist:['webpack/hot/poll?500']})],
    ....

[soldair]

We've done some tests and found that we cannot not support webpack or bundlers at all at this point.
They "require" files in a way that we cannot instrument them.

[mrdulin]

@soldair

It seems trace agent really doesn't support webpack, but it supports typescript compiler. I have tested it. Here is the repo:
https://github.com/mrdulin/nodejs-gcp/tree/master/src/stackdriver/trace/webpacked-server-code

So, if I use typescript as my server-side code and I want to use trace agent. I can't use webpack or bundlers to compile my code? The suggestion is to use typescript compiler?

[kjin]

Ultimately what is preventing us from working with transpiled code is whether require is re-implemented as part of the transpilation. TypeScript outputs require statements with no modification to its implementation, while AFAIK webpack will re-define require to reference other blocks of code in the same code, which violates our current assumption that it is the require that Node provides us.

[mrdulin]

@kjin Thanks for explaining. I have to choose TypeScript compiler instead of choosing webpack.

And I want to know do you have any plans for supporting webpack? Or, it's an impossible feature?

[kjin]

I would not expect TypeScript and webpack are not mutually exclusive, as they have fairly different purposes. That being said, unfortunately, we have no plans to support webpack, apologies for that!

[ghost]

Any updates on this? Is webpack support on your roadmap?