ConfigTailor

ConfigTailor is a hierarchical configuration compiler that produces a config file for all of your environments.

ConfigTailor makes it easy to manage your application configuration across any dimension including regions, regions, and cloud accounts. ConfigTailor is used to produce JSON configuration files that are consumed by your application in different environments.

Extensions

ConfigTailor allows you to substitute and extend JSON values from parent directories config.json. For example, at the top level you can add a config.json file with a global default value that you can override in subdirectories.

In the example above, we define in the top level root that "env": "root" and "name":"root". While prod, dev, and test are all subdirectories. We then override "env" in each subdirectory while only overriding "name" in prod. This results in both values overwritten in prod while only "name" is plumbed from root in "dev" and "test".

Example Config

Follow a directory pattern like:

config
├── config.json
├── dev
│   └── config.json
└── prod
    └── region
        └── config.json

file: config/config.json

{
    "global_value": "set_everywhere",
}

Variable Substitution

Example using the variable region.

file: config/prod/region/config.json

{
    "base_uri": "$region.telophase.dev"
}

Then you can run configtailor with a region mapping region:us-west-2,us-east-1,eu-west-1:

configtailor compile --rootpath=config --mappings=region:us-west-2,us-east-1,eu-west-1

Example output for config_generated/prod/us-west-2/config.json:

{
    "global_value": "set_everywhere",
    "base_uri": "us-west-2.telophase.dev"
}

While also outputting the following files:

• config_generated/prod/us-west-2/config.json
• config_generated/prod/us-east-1/config.json
• config_generated/prod/eu-west-1/config.json
• config_generated/dev/config.json

View more detailed outputs by looking in the example directory and the corresponding generated files in example_generated.

Installing

Install the configtailor CLI via go.

go install github.com/santiago-labs/configtailor@latest

Why?

In recent years, cell architecture has become more popular.

Application configuration becomes more complex with cell architecture. Copy and pasting config files is prone to errors, so we built ConfigTailor to edit all of our cell's configs in a single location.

For our configuration, we want:

• version control
• a single source of truth for each region's config

ConfigTailor enables this through a simple CLI that compiles configuration files from a source directory structure.

Obligatory Plug

If you like this project, at Telophase we are building tools to make it easier to make your application multi-region or stand up cells. We'd love to chat if you are building out cell infrastructure. Reach out to us at team@telophase.dev