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".