chore: expose SessionID (#1793)

* chore: expose session ID

* chore: add tests for session ID

* fix: use MustCompile

Author: mdelapenya

testcontainer.go

@@ -1 +1,28 @@
 package testcontainers
+
+import "github.com/testcontainers/testcontainers-go/internal/testcontainerssession"
+
+// SessionID returns a unique session ID for the current test session. Because each Go package
+// will be run in a separate process, we need a way to identify the current test session.
+// By test session, we mean:
+//   - a single "go test" invocation (including flags)
+//   - a single "go test ./..." invocation (including flags)
+//   - the execution of a single test or a set of tests using the IDE
+//
+// As a consequence, with the sole goal of aggregating test execution across multiple
+// packages, this variable will contain the value of the parent process ID (pid) of the current process
+// and its creation date, to use it to generate a unique session ID. We are using the parent pid because
+// the current process will be a child process of:
+//   - the process that is running the tests, e.g.: "go test";
+//   - the process that is running the application in development mode, e.g. "go run main.go -tags dev";
+//   - the process that is running the tests in the IDE, e.g.: "go test ./...".
+//
+// Finally, we will hash the combination of the "testcontainers-go:" string with the parent pid
+// and the creation date of that parent process to generate a unique session ID.
+//
+// This sessionID will be used to:
+//   - identify the test session, aggregating the test execution of multiple packages in the same test session.
+//   - tag the containers created by testcontainers-go, adding a label to the container with the session ID.
+func SessionID() string {
+	return testcontainerssession.SessionID()
+}

testcontainers_test.go

@@ -0,0 +1,85 @@
+package testcontainers
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"regexp"
+	"testing"
+)
+
+func TestSessionID(t *testing.T) {
+	t.Run("SessionID() returns a non-empty string", func(t *testing.T) {
+		sessionID := SessionID()
+		if sessionID == "" {
+			t.Error("SessionID() returned an empty string")
+		}
+	})
+
+	t.Run("Multiple calls to SessionID() return the same value", func(t *testing.T) {
+		sessionID1 := SessionID()
+		sessionID2 := SessionID()
+		if sessionID1 != sessionID2 {
+			t.Errorf("SessionID() returned different values: %s != %s", sessionID1, sessionID2)
+		}
+	})
+
+	t.Run("Multiple calls to SessionID() in multiple goroutines return the same value", func(t *testing.T) {
+		sessionID1 := ""
+		sessionID2 := ""
+
+		done := make(chan bool)
+		go func() {
+			sessionID1 = SessionID()
+			done <- true
+		}()
+
+		go func() {
+			sessionID2 = SessionID()
+			done <- true
+		}()
+
+		<-done
+		<-done
+
+		if sessionID1 != sessionID2 {
+			t.Errorf("SessionID() returned different values: %s != %s", sessionID1, sessionID2)
+		}
+	})
+
+	t.Run("SessionID() from different child processes returns the same value", func(t *testing.T) {
+		args := []string{"test", "./...", "-v", "-run", "TestSessionIDHelper"}
+		env := append(os.Environ(), "TESTCONTAINERS_SESSION_ID_HELPER=1")
+
+		re := regexp.MustCompile(">>>(.*)<<<")
+
+		cmd1 := exec.Command("go", args...)
+		cmd1.Env = env
+		stdoutStderr1, err := cmd1.CombinedOutput()
+		if err != nil {
+			t.Errorf("cmd1.Run() failed with %s", err)
+		}
+		sessionID1 := re.FindString(string(stdoutStderr1))
+
+		cmd2 := exec.Command("go", args...)
+		cmd2.Env = env
+		stdoutStderr2, err := cmd2.CombinedOutput()
+		if err != nil {
+			t.Errorf("cmd2.Run() failed with %s", err)
+		}
+		sessionID2 := re.FindString(string(stdoutStderr2))
+
+		if sessionID1 != sessionID2 {
+			t.Errorf("SessionID() returned different values: %s != %s", sessionID1, sessionID2)
+		}
+	})
+}
+
+// Not a real test, used to print out the session ID
+func TestSessionIDHelper(t *testing.T) {
+	if os.Getenv("TESTCONTAINERS_SESSION_ID_HELPER") == "" {
+		t.Skip("Not a real test, used as a test helper")
+	}
+
+	fmt.Printf(">>>%s<<<\n", SessionID())
+}