# Modifying Service Configs

> Modifying Service Configs is an Agent Skill for devops & security published in the golemcloud/golem repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.

Modifying service configuration types or defaults. Use when changing config structs, adding config fields, or updating default values for any Golem service.

- Skill name: `modifying-service-configs`
- Category: [DevOps & Security](https://www.openparable.com/skill/devops-security/1)
- Source: https://github.com/golemcloud/golem/blob/HEAD/.agents/skills/modifying-service-configs/SKILL.md
- Repository: golemcloud/golem (1,605 GitHub stars when collected)

## SKILL.md

# Modifying Service Configs

Golem services use a configuration system built on [Figment](https://github.com/SergioBenitez/Figment) via a custom `ConfigLoader`. Configuration defaults are serialized to TOML and env-var reference files that are checked into the repository and validated in CI.

## How Configuration Works

Each service has a configuration struct that implements:
- `Default` — provides default values
- `Serialize` / `Deserialize` — for TOML and env-var serialization
- `SafeDisplay` — for logging without exposing secrets

Services load config by merging (in order): defaults → TOML file → environment variables.

## Service Config Locations

| Service | Config struct | File |
|---------|--------------|------|
| Worker Executor | `GolemConfig` | `golem-worker-executor/src/services/golem_config.rs` |
| Worker Service | `WorkerServiceConfig` | `golem-worker-service/src/config.rs` |
| Registry Service | `RegistryServiceConfig` | `golem-registry-service/src/config.rs` |
| Shard Manager | `ShardManagerConfig` | `golem-shard-manager/src/shard_manager_config.rs` |
| Compilation Service | `ServerConfig` | `golem-component-compilation-service/src/config.rs` |

The all-in-one `golem` binary has its own merged config that combines multiple service configs.

## Modifying a Config

### Step 1: Edit the config struct

Add, remove, or modify fields in the appropriate config struct. Update the `Default` implementation if default values change.

### Step 2: Regenerate config files

```shell
cargo make generate-configs
```

This builds the service binaries and runs them with `--dump-config-default-toml` and `--dump-config-default-env-var` flags, producing reference files that reflect the current `Default` implementation.

### Step 3: Verify

```shell
cargo make build
```

### Step 4: Check configs match

CI runs `cargo make check-configs` which regenerates configs and diffs them against committed files. If this fails, you forgot to run `cargo make generate-configs`.

## Adding a New Config Field

1. Add the field to the config struct with a `serde` attribute if needed
2. Set its default value in the `Default` impl
3. Run `cargo make generate-configs` to update reference files
4. If the field requires a new environment variable, the env-var mapping is derived automatically from the field path

## Removing a Config Field

1. Remove the field from the struct and `Default` impl
2. Run `cargo make generate-configs`
3. Check for any code that references the removed field

## Nested Config Types

Many config structs compose sub-configs (e.g., `GolemConfig` contains `WorkersServiceConfig`, `BlobStoreServiceConfig`, etc.). When modifying a sub-config type that's shared across services, regenerate configs for all affected services — `cargo make generate-configs` handles this automatically.

## Checklist

1. Config struct modified with appropriate `serde` attributes
2. `Default` implementation updated
3. `cargo make generate-configs` run
4. Generated TOML and env-var files committed
5. `cargo make build` succeeds
6. `cargo make check-configs` passes (CI validation)
7. `cargo make fix` run before PR

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Source: https://www.openparable.com/skill/devops-security/modifying-service-configs (OpenParable). Cite the canonical URL above.