feat(host_sysctl): add host sysctl collector (#1676)

* feat(host_sysctl): add host sysctl collector

* chore: add examples

* Update pkg/collect/host_sysctl.go

Co-authored-by: Evans Mungai <[email protected]>

* chore: use sysctl package vs exec calls

* chore: make linter happy

* chore: make schemas

* chore: go back to sysctl exec

* chore: make linter happy

---------

Co-authored-by: Evans Mungai <[email protected]>

Author: JGAntunes

config/crds/troubleshoot.sh_collectors.yaml

@@ -17393,6 +17393,13 @@ spec:
                       - CIDRRangeAlloc
                       - desiredCIDR
                       type: object
+                    sysctl:
+                      properties:
+                        collectorName:
+                          type: string
+                        exclude:
+                          type: BoolString
+                      type: object
                     systemPackages:
                       properties:
                         amzn:

config/crds/troubleshoot.sh_hostcollectors.yaml

@@ -1719,6 +1719,13 @@ spec:
                       - CIDRRangeAlloc
                       - desiredCIDR
                       type: object
+                    sysctl:
+                      properties:
+                        collectorName:
+                          type: string
+                        exclude:
+                          type: BoolString
+                      type: object
                     systemPackages:
                       properties:
                         amzn:

config/crds/troubleshoot.sh_hostpreflights.yaml

@@ -1719,6 +1719,13 @@ spec:
                       - CIDRRangeAlloc
                       - desiredCIDR
                       type: object
+                    sysctl:
+                      properties:
+                        collectorName:
+                          type: string
+                        exclude:
+                          type: BoolString
+                      type: object
                     systemPackages:
                       properties:
                         amzn:

config/crds/troubleshoot.sh_supportbundles.yaml

@@ -20366,6 +20366,13 @@ spec:
                       - CIDRRangeAlloc
                       - desiredCIDR
                       type: object
+                    sysctl:
+                      properties:
+                        collectorName:
+                          type: string
+                        exclude:
+                          type: BoolString
+                      type: object
                     systemPackages:
                       properties:
                         amzn:

examples/collect/host/sysctl.yaml

@@ -0,0 +1,8 @@
+apiVersion: troubleshoot.sh/v1beta2
+kind: HostCollector
+metadata:
+  name: sysctl
+spec:
+  collectors:
+    - sysctl:
+        collectorName: sysctl

examples/preflight/host/sysctl.yaml

@@ -0,0 +1,10 @@
+apiVersion: troubleshoot.sh/v1beta2
+kind: HostPreflight
+metadata:
+  name: sysctl
+spec:
+  collectors:
+    - sysctl:
+        collectorName: sysctl
+  #TODO add analyzer once implemented
+  analyzers: []

pkg/apis/troubleshoot/v1beta2/hostcollector_shared.go

@@ -231,6 +231,10 @@ type HostDNS struct {
 	Hostnames         []string `json:"hostnames" yaml:"hostnames"`
 }
 
+type HostSysctl struct {
+	HostCollectorMeta `json:",inline" yaml:",inline"`
+}
+
 type HostCollect struct {
 	CPU                          *CPU                              `json:"cpu,omitempty" yaml:"cpu,omitempty"`
 	Memory                       *Memory                           `json:"memory,omitempty" yaml:"memory,omitempty"`
@@ -260,6 +264,7 @@ type HostCollect struct {
 	HostCGroups                  *HostCGroups                      `json:"cgroups,omitempty" yaml:"cgroups,omitempty"`
 	HostDNS                      *HostDNS                          `json:"dns,omitempty" yaml:"dns,omitempty"`
 	NetworkNamespaceConnectivity *HostNetworkNamespaceConnectivity `json:"networkNamespaceConnectivity,omitempty" yaml:"networkNamespaceConnectivity,omitempty"`
+	HostSysctl                   *HostSysctl                       `json:"sysctl,omitempty" yaml:"sysctl,omitempty"`
 }
 
 // GetName gets the name of the collector

pkg/apis/troubleshoot/v1beta2/zz_generated.deepcopy.go

@@ -101,6 +101,8 @@ func GetHostCollector(collector *troubleshootv1beta2.HostCollect, bundlePath str
 		return &CollectHostDNS{collector.HostDNS, bundlePath}, true
 	case collector.NetworkNamespaceConnectivity != nil:
 		return &CollectHostNetworkNamespaceConnectivity{collector.NetworkNamespaceConnectivity, bundlePath}, true
+	case collector.HostSysctl != nil:
+		return &CollectHostSysctl{collector.HostSysctl, bundlePath}, true
 	default:
 		return nil, false
 	}

pkg/collect/host_collector.go

@@ -0,0 +1,88 @@
+package collect
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"os/exec"
+	"regexp"
+
+	"github.com/pkg/errors"
+	troubleshootv1beta2 "github.com/replicatedhq/troubleshoot/pkg/apis/troubleshoot/v1beta2"
+	"k8s.io/klog/v2"
+)
+
+// Ensure `CollectHostSysctl` implements `HostCollector` interface at compile time.
+var _ HostCollector = (*CollectHostSysctl)(nil)
+
+// Helper var to allow stubbing `exec.Command` for tests
+var execCommand = exec.Command
+
+const HostSysctlPath = `host-collectors/system/sysctl.json`
+
+type CollectHostSysctl struct {
+	hostCollector *troubleshootv1beta2.HostSysctl
+	BundlePath    string
+}
+
+func (c *CollectHostSysctl) Title() string {
+	return hostCollectorTitleOrDefault(c.hostCollector.HostCollectorMeta, "Sysctl")
+}
+
+func (c *CollectHostSysctl) IsExcluded() (bool, error) {
+	return isExcluded(c.hostCollector.Exclude)
+}
+
+func (c *CollectHostSysctl) Collect(progressChan chan<- interface{}) (map[string][]byte, error) {
+	klog.V(2).Info("Running sysctl collector")
+	cmd := execCommand("sysctl", "-a")
+	out, err := cmd.Output()
+	if err != nil {
+		klog.V(2).ErrorS(err, "failed to run sysctl")
+		if exitErr, ok := err.(*exec.ExitError); ok {
+			return nil, errors.Wrapf(err, "failed to run sysctl exit-code=%d stderr=%s", exitErr.ExitCode(), exitErr.Stderr)
+		} else {
+			return nil, errors.Wrap(err, "failed to run sysctl")
+		}
+	}
+	values := parseSysctlParameters(out)
+
+	payload, err := json.Marshal(values)
+	if err != nil {
+		klog.V(2).ErrorS(err, "failed to marshal data to json")
+		return nil, errors.Wrap(err, "failed to marshal data to json")
+	}
+
+	output := NewResult()
+	output.SaveResult(c.BundlePath, HostSysctlPath, bytes.NewBuffer(payload))
+	klog.V(2).Info("Finished writing JSON output")
+	return output, nil
+}
+
+// Linux sysctl outputs <key> = <value> where in Darwin you get <key> : <value>
+// where <value> can be a string, number or multiple space separated strings
+var sysctlLineRegex = regexp.MustCompile(`(\S+)\s*(=|:)\s*(.*)$`)
+
+func parseSysctlParameters(output []byte) map[string]string {
+	scanner := bufio.NewScanner(bytes.NewReader(output))
+
+	result := map[string]string{}
+	for scanner.Scan() {
+		l := scanner.Text()
+		// <1:key> <2:separator> <3:value>
+		matches := sysctlLineRegex.FindStringSubmatch(l)
+
+		switch len(matches) {
+		// there are no matches for the value and separator, ignore and log
+		case 0, 1, 2:
+			klog.V(2).Infof("skipping sysctl line since we found no matches for it: %s", l)
+		// key exists but value could be empty, register as an empty string value but log something for reference
+		case 3:
+			klog.V(2).Infof("found no value for sysctl line, keeping it with an empty value: %s", l)
+			result[matches[1]] = ""
+		default:
+			result[matches[1]] = matches[3]
+		}
+	}
+	return result
+}