Add conn param and conn-skip flag to diagnostics command (#4946)

Add CONN param to control protocol so the elastic-agent can use CONN as
an additional parameter when requesting diagnostics actions. The CONN
param will be used to execute the optional connection request
diagnostics and included by default. Add a conn-skip flag to the
diagnostics command that will not send the CONN param so request
diagnostics are skipped.

changelog/fragments/1718660806-Add-diagnostics-skip-conn-flag.yaml

@@ -0,0 +1,32 @@
+# Kind can be one of:
+# - breaking-change: a change to previously-documented behavior
+# - deprecation: functionality that is being removed in a later release
+# - bug-fix: fixes a problem in a previous version
+# - enhancement: extends functionality but does not break or fix existing behavior
+# - feature: new functionality
+# - known-issue: problems that we are aware of in a given version
+# - security: impacts on the security of a product or a user’s deployment.
+# - upgrade: important information for someone upgrading from a prior version
+# - other: does not fit into any of the other categories
+kind: enhancement
+
+# Change summary; a 80ish characters long description of the change.
+summary: Add diagnostics skip-conn flag
+
+# Long description; in case the summary is not enough to describe the change
+# this field accommodate a description without length limits.
+# NOTE: This field will be rendered only for breaking-change and known-issue kinds at the moment.
+description: Add --skip-conn flag to elastic-agent diagnostics subcommand to skip collecting connection request diagnostics.
+
+# Affected component; a word indicating the component this changeset affects.
+component:
+
+# PR URL; optional; the PR number that added the changeset.
+# If not present is automatically filled by the tooling finding the PR where this changelog fragment has been added.
+# NOTE: the tooling supports backports, so it's able to fill the original PR number instead of the backport PR number.
+# Please provide it if you are adding a fragment for a different PR.
+pr: https://github.com/elastic/elastic-agent/pull/4946
+
+# Issue URL; optional; the GitHub issue related to this changeset (either closes or is part of).
+# If not present is automatically filled by the tooling with the issue linked to the PR number.
+#issue: https://github.com/owner/repo/1234

control_v2.proto

@@ -260,6 +260,7 @@ message DiagnosticAgentRequest {
 // DiagnosticAgentRequestAdditional is an enum of additional diagnostic metrics that can be requested from Elastic Agent.
 enum AdditionalDiagnosticRequest {
   CPU = 0;
+  CONN = 1;
 }
 
 // DiagnosticComponentsRequest is the message to request diagnostics from individual components.

internal/pkg/agent/cmd/diagnostics.go

@@ -36,6 +36,7 @@ func newDiagnosticsCommand(_ []string, streams *cli.IOStreams) *cobra.Command {
 
 	cmd.Flags().StringP("file", "f", "", "name of the output diagnostics zip archive")
 	cmd.Flags().BoolP("cpu-profile", "p", false, "wait to collect a CPU profile")
+	cmd.Flags().BoolP("skip-conn", "", false, "Skip connection request diagnostics")
 	cmd.Flags().Bool("exclude-events", false, "do not collect events log file")
 
 	return cmd
@@ -64,7 +65,8 @@ func diagnosticCmd(streams *cli.IOStreams, cmd *cobra.Command) error {
 	defer f.Close()
 
 	cpuProfile, _ := cmd.Flags().GetBool("cpu-profile")
-	agentDiag, unitDiags, compDiags, err := collectDiagnostics(ctx, streams, cpuProfile)
+	connSkip, _ := cmd.Flags().GetBool("skip-conn")
+	agentDiag, unitDiags, compDiags, err := collectDiagnostics(ctx, streams, cpuProfile, connSkip)
 	if err != nil {
 		return fmt.Errorf("failed collecting diagnostics: %w", err)
 	}
@@ -77,7 +79,7 @@ func diagnosticCmd(streams *cli.IOStreams, cmd *cobra.Command) error {
 	return nil
 }
 
-func collectDiagnostics(ctx context.Context, streams *cli.IOStreams, cpuProfile bool) ([]client.DiagnosticFileResult, []client.DiagnosticUnitResult, []client.DiagnosticComponentResult, error) {
+func collectDiagnostics(ctx context.Context, streams *cli.IOStreams, cpuProfile, connSkip bool) ([]client.DiagnosticFileResult, []client.DiagnosticUnitResult, []client.DiagnosticComponentResult, error) {
 	daemon := client.New()
 	err := daemon.Connect(ctx)
 	if err != nil {
@@ -86,10 +88,13 @@ func collectDiagnostics(ctx context.Context, streams *cli.IOStreams, cpuProfile
 	defer daemon.Disconnect()
 
 	var additionalDiags []cproto.AdditionalDiagnosticRequest
+	if !connSkip {
+		additionalDiags = append(additionalDiags, cproto.AdditionalDiagnosticRequest_CONN)
+	}
 	if cpuProfile {
 		// console will just hang while we wait for the CPU profile; print something so user doesn't get confused
 		fmt.Fprintf(streams.Out, "Creating diagnostics archive, waiting for CPU profile...\n")
-		additionalDiags = []cproto.AdditionalDiagnosticRequest{cproto.AdditionalDiagnosticRequest_CPU}
+		additionalDiags = append(additionalDiags, cproto.AdditionalDiagnosticRequest_CPU)
 	}
 
 	agentDiag, err := daemon.DiagnosticAgent(ctx, additionalDiags)