create-runtime-setting

Create a new RuntimeSetting implementation for the Datadog Agent. RuntimeSettings are settings that can be read and changed at runtime via: - The CLI: `agent config get <setting>`, `agent config set <setting> <value>`, `agent config list-runtime` - The HTTP API: `GET /config/{setting}`, `POST /config/{setting}` ## Instructions ### Step 1: Gather information from the user Use `AskUserQuestion` to collect the following. If `$ARGUMENTS` provides the setting name, skip that question. 1. **Setting name** (the config key, e.g. `log_payloads`, `dogstatsd_stats`): the name used to register and access the setting via the API. 2. **Value type**: What type of value does this setting hold? - Boolean (true/false) - Integer - String - String slice (list of strings) 3. **Description**: A human-readable description of what this setting controls (shown in `/config/list-runtime`). 4. **Hidden**: Should this setting be hidden from the public runtime settings list? (default: false) 5. **Scope**: Where should this setting live? - **Shared** (`pkg/config/settings/`) — Used by multiple agent services (agent, trace-agent, process-agent, etc.) - **Agent-specific** (`cmd/agent/subcommands/run/internal/settings/`) — Only used by the core agent 6. **Config key**: The `datadog.yaml` config key this setting maps to (e.g. `log_payloads`, `internal_profiling.enabled`). Often the same as the setting name, but can differ. 7. **Which services should register it**: Ask which services should have this setting registered: - Core Agent (`cmd/agent/subcommands/run/command.go`) - Cluster Agent (`cmd/cluster-agent/subcommands/start/command.go`) - Trace Agent (`cmd/trace-agent/subcommands/run/command.go`) - Process Agent (`cmd/process-agent/subcommands/run/command.go`) - Security Agent (`cmd/security-agent/subcommands/runtime/command.go`) - System Probe (`cmd/system-probe/subcommands/run/command.go`) - DogStatsD (`cmd/dogstatsd/subcommands/start/command.go`) ### Step 2: Read reference examples from the codebase Before writing any code, read the appropriate reference files to follow existing patterns exactly. 1. **Read the interface** defined in `comp/core/settings/component.go` to understand the `RuntimeSetting` methods. 2. **Read an existing implementation** matching the chosen value type. Use `Glob` with pattern `pkg/config/settings/runtime_setting_*.go` to list available examples, then read one that matches the desired type (boolean, integer, string, etc.). 3. **Read the test file** alongside the chosen reference to see the test pattern. 4. **Read a registration site**: Look at one of the `command.go` files listed in Step 1.7 to see how settings are added to the `Settings` map. ### Step 3: Create the RuntimeSetting implementation file **File naming convention**: `runtime_setting_<feature_name>.go` **File location**: - Shared: `pkg/config/settings/runtime_setting_<feature>.go` - Agent-specific: `cmd/agent/subcommands/run/internal/settings/runtime_setting_<feature>.go` Create the implementation following the patterns from the reference file read in Step 2. Every RuntimeSetting needs: 1. **Struct** with a `ConfigKey string` field 2. **Constructor** `New<Name>RuntimeSetting()` that sets the config key 3. **`Description()`** — returns the human-readable description 4. **`Hidden()`** — returns whether hidden from list-runtime 5. **`Name()`** — returns the config key 6. **`Get(config)`** — reads the current value using the appropriate typed getter 7. **`Set(config, v, source)`** — validates/converts the input value, then calls `config.Set()` **Type conversion in Set()**: for Boolean and Integer types, use the `GetBool(v)` / `GetInt(v)` helper functions from `pkg/config/settings` — these handle string-to-type conversion. For agent-specific settings, import the helpers via `settings "github.com/DataDog/datadog-agent/pkg/config/settings"`. ### Step 4: Create a unit test file Create a test file alongside the implementation: `runtime_setting_<feature>_test.go` Follow the test patterns from the reference test file read in Step 2. The test should verify: - `Name()`, `Description()`, `Hidden()` return expected values - `Get` returns the correct value from config - `Set` with a valid value updates the config - `Set` with a string representation works (e.g. `"true"`/`"false"` for bools) - `Set` with an invalid value returns an error ### Step 5: Register the setting Find the `settings.Params` provider in the appropriate `command.go` file(s) for each selected service (from Step 1.7). Add the new setting to the `Settings` map following the existing pattern in that file. The import alias convention and registration format are visible in the existing entries. ### Step 6: Verify 1. Run the new test: ```bash dda inv test --targets=<package_path> ``` 2. Run the linter on changed files: ```bash dda inv linter.go ``` 3. Report the results to the user. If tests or linting fail, fix the issues. ## Important Notes - The `RuntimeSetting` interface is defined in `comp/core/settings/component.go` - Helper functions `GetBool` and `GetInt` are in `pkg/config/settings/runtime_setting.go` - All `Set` methods receive a `model.Source` parameter for config source tracking — always pass it through to `config.Set()` - Settings are exposed via HTTP at `/config/{setting_name}` (GET to read, POST to write) and via the CLI: `agent config get <setting>`, `agent config set <setting> <value>`, `agent config list-runtime` - Follow existing code style: use the same comment patterns, error formatting, and naming conventions as existing RuntimeSettings ## Usage - `/create-runtime-setting` — Interactive: prompts for all details - `/create-runtime-setting my_new_setting` — Pre-fills the setting name, prompts for the rest