Substituting environment variables into HOCON config

Shin · July 7, 2016, 9:30am

Hi,

How would I pass environment variables so that they’re substituted into the typesafe/hocon config files?

For example, I’m trying to do
collectorPort=8080 ./snowplow-stream-collector-0.7.0 --config ~/downloads/collector.conf

So that I can change the port for dev, test and prod environments.

Thanks,

Shin · July 7, 2016, 12:29pm

The error raised is
Exception in thread "main" com.typesafe.config.ConfigException$NotResolved: port has not been resolved, you need to call Config#resolve(), see API docs for Config#resolve()

But nowhere in the code does resolve() get called so I think substitution is just not going to work at all.

github.com

Endource/snowplow/blob/r81-kangaroo-island-emu/2-collectors/scala-stream-collector/src/main/scala/com.snowplowanalytics.snowplow.collectors/scalastream/ScalaCollectorApp.scala#L71


    generated.Settings.version,
    generated.Settings.organization)
  )
)


// Mandatory config argument
val config = parser.option[Config](List("config"), "filename",
  "Configuration file.") { (c, opt) =>
  val file = new File(c)
  if (file.exists) {
    ConfigFactory.parseFile(file)
  } else {
    parser.usage("Configuration file \"%s\" does not exist".format(c))
    ConfigFactory.empty()
  }
}


parser.parse(args)


val rawConf = config.value.getOrElse(throw new RuntimeException("--config option must be provided"))
val collectorConfig = new CollectorConfig(rawConf)

The typesafe docs recommend using ConfigFactory.load() because it will call resolve for you whereas we’re only doing a parse. I’ll try to submit a PR if it works.

Shin · July 7, 2016, 5:15pm

Raised PR: https://github.com/snowplow/snowplow/pull/2798 https://github.com/snowplow/kinesis-s3/pull/67

alex · July 7, 2016, 8:09pm

Thanks @Shin! Much appreciated…

christoph-buente · July 8, 2016, 10:14am

Thx @Shin, i actually tried to do exactly that, but i always thought, i was doing it wrong. So i gave up on environment variables.

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Substituting environment variables into HOCON config

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