Sridharan Kuppa skuppa

Merge collection by group by

case class Channel(name: String,
                  deviceIds: List[String])

object Channel {
  def copy(c: Channel, newDevicesIds: List[String]) = c.copy(deviceIds = if(c.deviceIds == newDevicesIds) c.deviceIds else c.deviceIds ::: newDevicesIds)
}

def mergeDevices(channels: List[Channel]): Channel = { channels.foldLeft(channels.head) ((r, c) =&gt; Channel.copy(r, c.deviceIds)) }

Export keychain into plain text

security dump-keychain -d login.keychain > keychain.txt

-- account : username
-- data : password

Images

Delete untagged docker images

docker rmi $(docker images -q --filter "dangling=true")

Logs

Read the docker log

docker logs -f

Spring boot property loading order

Spring Boot looks for properties using a specific order:

Command line arguments
Java System properties (System.getProperties())
OS environment variables
JNDI attributes from java:comp/env
A RandomValuePropertySource that only has properties in random.*
Application properties outside of your packaged jar (application.properties including YAML and profile variants)
Application properties packaged inside your jar (application.properties including YAML and profile variants)

When Bad Request happens, most of the problem is in the data serialization and de-serialization. To get the detailed stack trace add the following in the log4j configuration or similar for logback.

    <logger name="org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod">
        <level value="trace"/>
    </logger>

Managing ESXi requires one needs to have vSphere ESXi Cli tool to be installed. But, ESXi server itself has commands to manage the guest OS.

Login to console

ssh root@esxihost

Get all guest vms

# vim-cmd vmsvc/getallvms

JDBC Driver

Name	Value
artifact	postgresql:postgresql:8.4-702.jdbc3
driver	org.postgresql.Driver
JDBC url	jdbc:postgresql://localhost:5432/testdb

Connecting Heroku Postgres

Use ssl to true and sslfactory as NonValidatingFactory

Remove staged file after updating the `.gitignore`

$ echo 'out/' >> .gitignore
$ git rm -r --cached out/

Shelve Changes using Branch

If file is not committed locally

Tips to work with heroku

Adding key to heroku

It is required so you can push code heroku's git server and deploy

# Make sure the keys are available
ssh-add -l

# Add keys to heroku
heroku keys:add

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