adding version check

pkg/diagnostic/prom/version/check.go

@@ -0,0 +1,108 @@
+package version
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	net "net/http"
+	"os"
+	"os/exec"
+
+	"github.com/cloudzero/cloudzero-agent-validator/pkg/config"
+	"github.com/cloudzero/cloudzero-agent-validator/pkg/diagnostic"
+	"github.com/cloudzero/cloudzero-agent-validator/pkg/logging"
+	"github.com/cloudzero/cloudzero-agent-validator/pkg/status"
+	"github.com/sirupsen/logrus"
+)
+
+const DiagnosticPrometheusVersion = config.DiagnosticPrometheusVersion
+
+type checker struct {
+	cfg    *config.Settings
+	logger *logrus.Entry
+}
+
+func NewProvider(ctx context.Context, cfg *config.Settings) diagnostic.Provider {
+	return &checker{
+		cfg: cfg,
+		logger: logging.NewLogger().
+			WithContext(ctx).WithField(logging.OpField, "prom"),
+	}
+}
+
+func (c *checker) Check(ctx context.Context, _ *net.Client, accessor status.Accessor) error {
+	if len(c.cfg.Prometheus.Executable) == 0 {
+		accessor.AddCheck(&status.StatusCheck{
+			Name:  DiagnosticPrometheusVersion,
+			Error: "no prometheus binary available at configured location",
+		})
+		return nil
+	}
+
+	versionData, err := c.GetVersion(ctx)
+	if err != nil {
+		accessor.AddCheck(
+			&status.StatusCheck{
+				Name:  DiagnosticPrometheusVersion,
+				Error: err.Error(),
+			})
+		return nil
+	}
+
+	accessor.WriteToReport(func(s *status.ClusterStatus) {
+		s.AgentVersion = string(versionData)
+		s.Checks = append(s.Checks, &status.StatusCheck{Name: DiagnosticPrometheusVersion, Passing: true})
+	})
+	return nil
+}
+
+func (c *checker) GetVersion(ctx context.Context) ([]byte, error) {
+	executable := c.cfg.Prometheus.Executable
+	if len(executable) == 0 {
+		return nil, fmt.Errorf("no prometheus binary available at configured location")
+	}
+
+	fi, err := os.Stat(executable)
+	if os.IsNotExist(err) {
+		return nil, fmt.Errorf("prometheus executable not found: %w", err)
+	}
+	if fi.Mode()&0111 == 0 {
+		return nil, fmt.Errorf("prometheus executable is not executable: %s", executable)
+	}
+
+	// create the raw output fle
+	rawOutput, err := os.CreateTemp(os.TempDir(), ".promver.*")
+	if err != nil {
+		return nil, fmt.Errorf("failed to create raw prometheus version output file: %w", err)
+	}
+	defer func() {
+		_ = rawOutput.Close()
+		_ = os.Remove(rawOutput.Name())
+	}()
+
+	// Build the command and Exec the scanner
+	cmd := exec.CommandContext(ctx, executable, "--version")
+
+	// capture the output
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	cmd.Stdout = rawOutput
+
+	// Now run the app
+	if err := cmd.Run(); err != nil {
+		return nil, fmt.Errorf("failed to run prometheus: %w", err)
+	}
+
+	// make sure all bytes are written from the standard output
+	if err := rawOutput.Sync(); err != nil {
+		return nil, fmt.Errorf("failed to sync raw prometheus output file: %w", err)
+	}
+
+	// seek to the beginning of the file for reading.
+	if _, err := rawOutput.Seek(0, 0); err != nil {
+		return nil, fmt.Errorf("failed to seek to the beginning of the raw prometheus output file: %w", err)
+	}
+
+	// read the results into a byte slice
+	return os.ReadFile(rawOutput.Name())
+}

pkg/diagnostic/prom/version/check_test.go

@@ -0,0 +1,74 @@
+package version_test
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/cloudzero/cloudzero-agent-validator/pkg/config"
+	"github.com/cloudzero/cloudzero-agent-validator/pkg/diagnostic/prom/version"
+	"github.com/cloudzero/cloudzero-agent-validator/pkg/status"
+)
+
+func makeReport() status.Accessor {
+	return status.NewAccessor(&status.ClusterStatus{})
+}
+
+func TestChecker_GetVersion(t *testing.T) {
+	tests := []struct {
+		name       string
+		executable string
+		expected   bool
+	}{
+		{
+			name:       "ExecutableNotFound",
+			executable: "/path/to/nonexistent/prometheus",
+			expected:   false,
+		},
+		{
+			name:       "ExecutableEmpty",
+			executable: "",
+			expected:   false,
+		},
+		{
+			name:       "Success",
+			executable: getPromExecutablePath(),
+			expected:   true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := &config.Settings{
+				Prometheus: config.Prometheus{
+					Executable: tt.executable,
+				},
+			}
+			provider := version.NewProvider(context.Background(), cfg)
+			accessor := makeReport()
+
+			err := provider.Check(context.Background(), nil, accessor)
+			assert.NoError(t, err)
+
+			accessor.ReadFromReport(func(s *status.ClusterStatus) {
+				assert.Len(t, s.Checks, 1)
+				for _, c := range s.Checks {
+					assert.Equal(t, tt.expected, c.Passing)
+				}
+				if tt.expected {
+					assert.NotEmpty(t, s.AgentVersion)
+				}
+			})
+		})
+	}
+}
+
+func getPromExecutablePath() string {
+	wd, err := os.Getwd()
+	if err != nil {
+		panic(err)
+	}
+	return wd + "/testdata/prometheus"
+}

pkg/diagnostic/prom/version/testdata/prometheus

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+echo "  prometheus, version 2.50.1 (branch: HEAD, revision: 8c9b0285360a0b6288d76214a75ce3025bce4050)"
+echo "  build user:       root@6213bb3ee580"
+echo "  build date:       20240226-11:38:47"
+echo "  go version:       go1.21.7"
+echo "  platform:         linux/arm64"
+echo "  tags:             netgo,builtinassets,stringlabels"