Deploying updated health checks

gateway/Dockerfile

@@ -12,4 +12,4 @@ RUN go build -o /go/bin/porters
 
 EXPOSE 9000
 
-CMD ["porters", "gateway"]
+CMD ["sh", "-c", "ulimit -n 65536 && exec /go/bin/porters gateway"]

gateway/go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/lib/pq v1.10.9
 	github.com/prometheus/client_golang v1.19.0
 	github.com/redis/go-redis/v9 v9.4.0
+	golang.org/x/sys v0.25.0
 )
 
 require (
@@ -18,6 +19,5 @@ require (
 	github.com/prometheus/client_model v0.5.0 // indirect
 	github.com/prometheus/common v0.48.0 // indirect
 	github.com/prometheus/procfs v0.12.0 // indirect
-	golang.org/x/sys v0.16.0 // indirect
 	google.golang.org/protobuf v1.33.0 // indirect
 )

gateway/go.sum

@@ -34,8 +34,8 @@ github.com/redis/go-redis/v9 v9.4.0 h1:Yzoz33UZw9I/mFhx4MNrB6Fk+XHO1VukNcCa1+lwy
 github.com/redis/go-redis/v9 v9.4.0/go.mod h1:hdY0cQFCN4fnSYT6TkisLufl/4W5UIXyv0b/CLO2V2M=
 github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
-golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
-golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
+golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
 google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

gateway/proxy/health.go

@@ -1,14 +1,71 @@
 package proxy
 
 import (
+	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
+	"os"
+	"porters/common"
 	"porters/db"
+
+	"golang.org/x/sys/unix"
 )
 
-// TODO other healthchecks should be added
+type HealthStatus struct {
+	CacheHealth *common.HealthCheckStatus `json:"cache_health"` // Use the correct type here
+}
+
+// New function to check file descriptor health and log the results using slog
+func checkFileDescriptorHealth() bool {
+	var rLimit unix.Rlimit
+
+	// Get the max number of allowed file descriptors
+	err := unix.Getrlimit(unix.RLIMIT_NOFILE, &rLimit)
+	if err != nil {
+		slog.Error("Error retrieving file descriptor limit", "error", err)
+		return false
+	}
+
+	// Get the actual number of file descriptors in use
+	files, err := os.ReadDir("/proc/self/fd")
+	if err != nil {
+		slog.Error("Error reading /proc/self/fd", "error", err)
+		return false
+	}
+	fdUsage := uint64(len(files))
+
+	healthy := fdUsage < rLimit.Cur*80/100
+
+	// Log the file descriptor information using slog
+	slog.Info("File Descriptor Usage",
+		"max", rLimit.Cur,
+		"used", fdUsage,
+		"healthy", healthy)
+
+	return healthy
+}
+
+// Update your healthHandler to log file descriptor health but not expose it
 func healthHandler(resp http.ResponseWriter, req *http.Request) {
-	hc := (&db.Cache{}).Healthcheck()
+	// Existing cache health check
+	cacheHealth := (&db.Cache{}).Healthcheck()
+
+	// Log file descriptor health and determine if the server is healthy
+	fdHealthy := checkFileDescriptorHealth()
+
+	// Only return the non-sensitive health information (cache health)
+	healthStatus := HealthStatus{
+		CacheHealth: cacheHealth,
+	}
+
+	// Marshal the health status into JSON
 	resp.Header().Set("Content-Type", "application/json")
-	io.WriteString(resp, hc.ToJson())
+
+	if fdHealthy {
+		io.WriteString(resp, healthStatus.CacheHealth.ToJson())
+	} else {
+		resp.WriteHeader(http.StatusInternalServerError)
+		io.WriteString(resp, fmt.Sprintf(`{"error": "file descriptor limit exceeded"}`))
+	}
 }