Postgres: Switch the datasource plugin from lib/pq to pgx (#81353)

* postgres: switch from lib/pq to pgx

* postgres: improved tls handling

pkg/tsdb/grafana-postgresql-datasource/tls/tls_test_helpers.go

@@ -0,0 +1,105 @@
+package tls
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"math/big"
+	"os"
+	"time"
+)
+
+func CreateRandomRootCertBytes() ([]byte, error) {
+	cert := x509.Certificate{
+		SerialNumber: big.NewInt(42),
+		Subject: pkix.Name{
+			CommonName: "test1",
+		},
+		NotBefore:             time.Now(),
+		NotAfter:              time.Now().AddDate(10, 0, 0),
+		IsCA:                  true,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+		KeyUsage:              x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
+		BasicConstraintsValid: true,
+	}
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		return nil, err
+	}
+
+	bytes, err := x509.CreateCertificate(rand.Reader, &cert, &cert, &key.PublicKey, key)
+	if err != nil {
+		return nil, err
+	}
+
+	return pem.EncodeToMemory(&pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: bytes,
+	}), nil
+}
+
+func CreateRandomClientCert() ([]byte, []byte, error) {
+	caKey, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	keyBytes := pem.EncodeToMemory(&pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: x509.MarshalPKCS1PrivateKey(key),
+	})
+
+	caCert := x509.Certificate{
+		SerialNumber: big.NewInt(42),
+		Subject: pkix.Name{
+			CommonName: "test1",
+		},
+		NotBefore:             time.Now(),
+		NotAfter:              time.Now().AddDate(10, 0, 0),
+		IsCA:                  true,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
+		KeyUsage:              x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
+		BasicConstraintsValid: true,
+	}
+
+	cert := x509.Certificate{
+		SerialNumber: big.NewInt(2019),
+		Subject: pkix.Name{
+			CommonName: "test1",
+		},
+		NotBefore:   time.Now(),
+		NotAfter:    time.Now().AddDate(10, 0, 0),
+		ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
+		KeyUsage:    x509.KeyUsageDigitalSignature,
+	}
+
+	certData, err := x509.CreateCertificate(rand.Reader, &cert, &caCert, &key.PublicKey, caKey)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	certBytes := pem.EncodeToMemory(&pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: certData,
+	})
+
+	return keyBytes, certBytes, nil
+}
+
+func newMockReadFile(data map[string]([]byte)) ReadFileFunc {
+	return func(path string) ([]byte, error) {
+		bytes, ok := data[path]
+		if !ok {
+			return nil, os.ErrNotExist
+		}
+		return bytes, nil
+	}
+}