Readme and docs (#52)

- Make system DB private
- Update README
- Add docs for https://pkg.go.dev/github.com/dbos-inc/dbos-transact-go

Author: maxdml

README.md

@@ -1,17 +1,23 @@
 <div align="center">
 
-# DBOS Transact: Lightweight Durable Workflows
+[![Go Reference](https://pkg.go.dev/badge/github.com/dbos-inc/dbos-transact-go.svg)](https://pkg.go.dev/github.com/dbos-inc/dbos-transact-go)
+[![Go Report Card](https://goreportcard.com/badge/github.com/dbos-inc/dbos-transact-go)](https://goreportcard.com/report/github.com/dbos-inc/dbos-transact-go)
+[![GitHub release (latest SemVer)](https://img.shields.io/github/v/release/dbos-inc/dbos-transact-go?sort=semver)](https://github.com/dbos-inc/dbos-transact-go/releases)
+
+
+# DBOS Transact: Lightweight Durable Workflow Orchestration with Postgres
 
 #### [Documentation](https://docs.dbos.dev/) &nbsp;&nbsp;•&nbsp;&nbsp;  [Examples](https://docs.dbos.dev/examples) &nbsp;&nbsp;•&nbsp;&nbsp; [Github](https://github.com/dbos-inc) &nbsp;&nbsp;•&nbsp;&nbsp; [Discord](https://discord.com/invite/jsmC6pXGgX)
 </div>
 
----
+#### This Golang version of DBOS Transact is in Alpha!
+For production ready Transacts, check our [Python](https://github.com/dbos-inc/dbos-transact-py) and [TypeScript](https://github.com/dbos-inc/dbos-transact-ts) versions.
 
-This package is in alpha -- the roadmap of missing features is listed [below](#roadmap).
+---
 
 ## What is DBOS?
 
-DBOS provides lightweight durable workflows on top of Postgres. Instead of managing your own workflow orchestrator or task queue system, you can use DBOS to add durable workflows and queues to your program in just a few lines of code.
+DBOS provides lightweight durable workflow orchestration on top of Postgres. Instead of managing your own workflow orchestrator or task queue system, you can use DBOS to add durable workflows and queues to your program in just a few lines of code.
 
 
 ## When Should I Use DBOS?
@@ -33,36 +39,67 @@ If your program ever fails, when it restarts all your workflows will automatical
 You add durable workflows to your existing Golang program by registering ordinary functions as workflows or running them as steps:
 
 ```golang
-var (
-    wf = dbos.WithWorkflow(workflow)
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/dbos-inc/dbos-transact-go/dbos"
 )
 
-func workflow(ctx context.Context, _ string) (string, error) {
-    _, err := dbos.RunAsStep(ctx, step1, "")
-    if err != nil {
-        return "", err
-    }
-    return dbos.RunAsStep(ctx, step2, "")
+func workflow(dbosCtx dbos.DBOSContext, _ string) (string, error) {
+	_, err := dbos.RunAsStep(dbosCtx, func(ctx context.Context) (string, error) {
+		return stepOne(ctx)
+	})
+	if err != nil {
+		return "", err
+	}
+	return dbos.RunAsStep(dbosCtx, func(ctx context.Context) (string, error) {
+		return stepTwo(ctx)
+	})
 }
 
-func step1(ctx context.Context, _ string) (string, error) {
-    fmt.Println("Executing step 1")
-    return "Step 1 completed", nil
+func stepOne(ctx context.Context) (string, error) {
+	fmt.Println("Step one completed!")
+	return "Step 1 completed", nil
 }
 
-func step2(ctx context.Context, _ string) (string, error) {
-    fmt.Println("Executing step 2")
-    return "Step 2 completed - Workflow finished successfully", nil
+func stepTwo(ctx context.Context) (string, error) {
+	fmt.Println("Step two completed!")
+	return "Step 2 completed - Workflow finished successfully", nil
 }
-
 func main() {
-    err := dbos.Launch()
-    if err != nil {
-        panic(err)
-    }
-    defer dbos.Shutdown()
-
-    wf(context.Background(), "hello DBOS")
+    // Initialize a DBOS context
+	ctx, err := dbos.NewDBOSContext(dbos.Config{
+		DatabaseURL: os.Getenv("DBOS_SYSTEM_DATABASE_URL"),
+		AppName:     "myapp",
+	})
+	if err != nil {
+		panic(err)
+	}
+
+    // Register a workflow
+	dbos.RegisterWorkflow(ctx, workflow)
+
+    // Launch DBOS
+	err = ctx.Launch()
+	if err != nil {
+		panic(err)
+	}
+	defer ctx.Cancel()
+
+    // Run a durable workflow and get its result
+	handle, err := dbos.RunAsWorkflow(ctx, workflow, "")
+	if err != nil {
+		panic(err)
+	}
+	res, err := handle.GetResult()
+	if err != nil {
+		panic(err)
+	}
+	fmt.Println("Workflow result:", res)
 }
 ```
 
@@ -90,36 +127,56 @@ You can add queues to your workflows in just a couple lines of code.
 They don't require a separate queueing service or message broker&mdash;just Postgres.
 
 ```golang
-var (
-    queue  = dbos.NewWorkflowQueue("example-queue")
-    taskWf = dbos.WithWorkflow(task)
+package main
+
+import (
+    "fmt"
+    "os"
+    "time"
+
+    "github.com/dbos-inc/dbos-transact-go/dbos"
 )
 
-func task(ctx context.Context, i int) (int, error) {
-    time.Sleep(5 * time.Second)
+func task(ctx dbos.DBOSContext, i int) (int, error) {
+    ctx.Sleep(5 * time.Second)
     fmt.Printf("Task %d completed\n", i)
     return i, nil
 }
 
 func main() {
-    err := dbos.Launch()
+    // Initialize a DBOS context
+    ctx, err := dbos.NewDBOSContext(dbos.Config{
+        DatabaseURL: os.Getenv("DBOS_SYSTEM_DATABASE_URL"),
+        AppName:     "myapp",
+    })
     if err != nil {
         panic(err)
     }
-    defer dbos.Shutdown()
 
+    // Register the workflow and create a durable queue
+    dbos.RegisterWorkflow(ctx, task)
+    queue := dbos.NewWorkflowQueue(ctx, "queue")
+
+    // Launch DBOS
+    err = ctx.Launch()
+    if err != nil {
+        panic(err)
+    }
+    defer ctx.Cancel()
+
+    // Enqueue tasks and gather results
     fmt.Println("Enqueuing workflows")
     handles := make([]dbos.WorkflowHandle[int], 10)
     for i := range 10 {
-        handle, err := taskWf(context.Background(), i, dbos.WithQueue(queue.Name))
+        handle, err := dbos.RunAsWorkflow(ctx, task, i, dbos.WithQueue(queue.Name))
         if err != nil {
             panic(fmt.Sprintf("failed to enqueue step %d: %v", i, err))
         }
         handles[i] = handle
     }
     results := make([]int, 10)
     for i, handle := range handles {
-        result, err := handle.GetResult(context.Background())
+        result, err := handle.GetResult()
         if err != nil {
             panic(fmt.Sprintf("failed to get result for step %d: %v", i, err))
         }
@@ -130,47 +187,115 @@ func main() {
 ```
 </details>
 
+<details><summary><strong>🎫 Exactly-Once Event Processing</strong></summary>
+
+####
+
+Use DBOS to build reliable webhooks, event listeners, or Kafka consumers by starting a workflow exactly-once in response to an event.
+Acknowledge the event immediately while reliably processing it in the background.
+
+For example:
+
+```golang
+_, err := dbos.RunAsWorkflow(ctx, task, i, dbos.WithWorkflowID(exactlyOnceEventID))
+```
+</details>
+
+<details><summary><strong>📅 Durable Scheduling</strong></summary>
+
+####
+
+Schedule workflows using cron syntax, or use durable sleep to pause workflows for as long as you like (even days or weeks) before executing.
+
+```golang
+dbos.RegisterWorkflow(dbosCtx, func(ctx dbos.DBOSContext, scheduledTime time.Time) (string, error) {
+    return fmt.Sprintf("Workflow executed at %s", scheduledTime), nil
+}, dbos.WithSchedule("* * * * * *")) // Every second
+```
+
+You can add a durable sleep to any workflow with a single line of code.
+It stores its wakeup time in Postgres so the workflow sleeps through any interruption or restart, then always resumes on schedule.
+
+```golang
+func workflow(ctx dbos.DBOSContext, duration time.Duration) (string, error) {
+    ctx.Sleep(duration)
+    return fmt.Sprintf("Workflow slept for %s", duration), nil
+}
+
+handle, err := dbos.RunAsWorkflow(dbosCtx, workflow, time.Second*5)
+_, err = handle.GetResult()
+```
+
+</details>
+
+<details><summary><strong>📫 Durable Notifications</strong></summary>
+
+####
+
+Pause your workflow executions until a notification is received, or emit events from your workflow to send progress updates to external clients.
+All notifications are stored in Postgres, so they can be sent and received with exactly-once semantics.
+Set durable timeouts when waiting for events, so you can wait for as long as you like (even days or weeks) through interruptions or restarts, then resume once a notification arrives or the timeout is reached.
+
+For example, build a reliable billing workflow that durably waits for a notification from a payments service, processing it exactly-once:
+
+```golang
+func sendWorkflow(ctx dbos.DBOSContext, message string) (string, error) {
+    err := dbos.Send(ctx, dbos.WorkflowSendInput[string]{
+        DestinationID: "receiverID",
+        Topic:         "topic",
+        Message:       message,
+    })
+}
+
+func receiveWorkflow(ctx dbos.DBOSContext, topic string) (string, error) {
+    return dbos.Recv[string](ctx, dbos.WorkflowRecvInput{Topic: topic, Timeout: 48 * time.Hour})
+}
+
+// Start a receiver in the background
+recvHandle, err := dbos.RunAsWorkflow(dbosCtx, receiveWorkflow, "topic", dbos.WithWorkflowID("receiverID"))
+
+// Send a message
+sendHandle, err := dbos.RunAsWorkflow(dbosCtx, sendWorkflow, "hola!")
+_, err = sendHandle.GetResult()
+
+// Eventually get the response
+recvResult, err := recvHandle.GetResult()
+```
+
+</details>
+
+
 ## DBOS workflows
 
 A workflow can be any function with the following signature:
 ```golang
-type WorkflowFunc[P any, R any] func(ctx context.Context, input P) (R, error)
+type GenericWorkflowFunc[P any, R any] func(ctx context.Context, input P) (R, error)
 ```
 
-`P` and `R` must be concrete types (not `any`).
+To register a workflow call `dbos.RegisterWorkflow(dbosCtx, workflow)` after having initialized a DBOS Context. Workflows can only be registered before DBOS is launched.
 
-Workflows must be registered with DBOS using the `WithWorkflow` method before DBOS is launched.
 
 Workflows can run steps, which can be any function with the following signature:
 ```golang
-type StepFunc[P any, R any] func(ctx context.Context, input P) (R, error)
+type GenericStepFunc[R any] func(ctx context.Context) (R, error)
 ```
 
-To run a step within a workflow, use `RunAsStep`. Importantly, you must pass to `RunAsStep` the context received in the workflow function.
+To run a step within a workflow, use `RunAsStep`. Importantly, you must pass to `RunAsStep` the context received in the workflow function (see examples above.)
 
 The input and output of workflows and steps are memoized in your Postgres database for workflow recovery. Under the hood, DBOS uses the [encoding/gob](https://pkg.go.dev/encoding/gob) package for serialization (this means that only exported fields will be memoized and types without exported fields will generate an error.)
 
-## Roadmap:
-* logging for DBOS internals -- consider accepting a user provided logger
-* OTel trace generation and export
-* OTel logs -- consider leveraging the user provided logger
-* config?
-* go doc
-* workflows send and recv
-* workflows set and get event
-* workflow cancellation maps
-* queue dedup
-* queue priority
-* workflow timeouts
-* DBOS Client
-* datasources & transactions
-
 ## Getting started
 
 Install the DBOS Transact package in your program:
 
 ```shell
-github.com/dbos-inc/dbos-transact-go
+go get github.com/dbos-inc/dbos-transact-go
 ```
 
-You can store and export a Postgres connection string in the `DBOS_SYSTEM_DATABASE_URL` environment variable for DBOS to manage your workflows state. By default, DBOS will use `postgres://postgres:${PGPASSWORD}@localhost:5432/dbos?sslmode=disable`.
+You can store and export a Postgres connection string in the `DBOS_SYSTEM_DATABASE_URL` environment variable for DBOS to manage your workflows state. By default, DBOS will use `postgres://postgres:${PGPASSWORD}@localhost:5432/dbos?sslmode=disable`.
+
+
+## ⭐️ Like this project?
+
+[Star it on GitHub](https://github.com/dbos-inc/dbos-transact-go)  
+[![GitHub Stars](https://img.shields.io/github/stars/dbos-inc/dbos-transact-go?style=social)](https://github.com/dbos-inc/dbos-transact-go)