From 7bc8fc8d836890f9c09cf9f030ca2e2d3dcf4254 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Thu, 12 Oct 2023 05:45:17 -0700
Subject: [PATCH 01/16] Remove context and handle cancellation internally
 instead

---
 .../artifact/download/http/progress_reporter.go        | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go b/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
index 491646b3ab5..21aca351dc4 100644
--- a/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
+++ b/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
@@ -66,7 +66,7 @@ func (dp *downloadProgressReporter) Report(ctx context.Context) {
 		defer t.Stop()
 		for {
 			select {
-			case <-ctx.Done():
+			case <-dp.done:
 				return
 			case <-dp.done:
 				return
@@ -107,6 +107,8 @@ func (dp *downloadProgressReporter) ReportComplete() {
 	for _, obs := range dp.progressObservers {
 		obs.ReportCompleted(dp.sourceURI, timePast, bytesPerSecond)
 	}
+
+	dp.close()
 }
 
 // ReportFailed reports the failure of a download to registered observers. Callers MUST call
@@ -132,4 +134,10 @@ func (dp *downloadProgressReporter) ReportFailed(err error) {
 	for _, obs := range dp.progressObservers {
 		obs.ReportFailed(dp.sourceURI, timePast, downloaded, dp.length, percentComplete, bytesPerSecond, err)
 	}
+
+	dp.close()
+}
+
+func (dp *downloadProgressReporter) close() {
+	dp.done <- struct{}{}
 }

From b6bd1ead95e30aea49850f6c4ca9eaf5697bd8d0 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Thu, 12 Oct 2023 05:47:51 -0700
Subject: [PATCH 02/16] More optimizations

---
 .../upgrade/artifact/download/http/progress_reporter.go   | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go b/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
index 21aca351dc4..3c9561937ac 100644
--- a/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
+++ b/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
@@ -107,8 +107,6 @@ func (dp *downloadProgressReporter) ReportComplete() {
 	for _, obs := range dp.progressObservers {
 		obs.ReportCompleted(dp.sourceURI, timePast, bytesPerSecond)
 	}
-
-	dp.close()
 }
 
 // ReportFailed reports the failure of a download to registered observers. Callers MUST call
@@ -134,10 +132,4 @@ func (dp *downloadProgressReporter) ReportFailed(err error) {
 	for _, obs := range dp.progressObservers {
 		obs.ReportFailed(dp.sourceURI, timePast, downloaded, dp.length, percentComplete, bytesPerSecond, err)
 	}
-
-	dp.close()
-}
-
-func (dp *downloadProgressReporter) close() {
-	dp.done <- struct{}{}
 }

From 28ce34f4682112cb8a068774714ecf0b3ba41c87 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Thu, 12 Oct 2023 09:45:53 -0700
Subject: [PATCH 03/16] Add back context

---
 .../upgrade/artifact/download/http/progress_reporter.go         | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go b/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
index 3c9561937ac..2df81be6018 100644
--- a/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
+++ b/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
@@ -66,6 +66,8 @@ func (dp *downloadProgressReporter) Report(ctx context.Context) {
 		defer t.Stop()
 		for {
 			select {
+			case <-ctx.Done():
+				return
 			case <-dp.done:
 				return
 			case <-dp.done:

From 0ec900a990dd0159ec86ab8b476cde57c6dcd1f7 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Mon, 2 Oct 2023 17:55:11 -0700
Subject: [PATCH 04/16] Adding FSM for upgrades

---
 go.mod                                        |   1 +
 go.sum                                        |   2 +
 internal/pkg/agent/application/upgrade/fsm.go | 108 ++++++++++++++++++
 .../pkg/agent/application/upgrade/fsm_test.go |  42 +++++++
 4 files changed, 153 insertions(+)
 create mode 100644 internal/pkg/agent/application/upgrade/fsm.go
 create mode 100644 internal/pkg/agent/application/upgrade/fsm_test.go

diff --git a/go.mod b/go.mod
index 847bf6d35c5..fa00c749819 100644
--- a/go.mod
+++ b/go.mod
@@ -35,6 +35,7 @@ require (
 	github.com/joeshaw/multierror v0.0.0-20140124173710-69b34d4ec901
 	github.com/josephspurrier/goversioninfo v0.0.0-20190209210621-63e6d1acd3dd
 	github.com/kardianos/service v1.2.1-0.20210728001519-a323c3813bc7
+	github.com/looplab/fsm v1.0.1
 	github.com/magefile/mage v1.15.0
 	github.com/mitchellh/gox v1.0.1
 	github.com/mitchellh/hashstructure v1.1.0
diff --git a/go.sum b/go.sum
index 708ac86b4fc..c6d2633bfea 100644
--- a/go.sum
+++ b/go.sum
@@ -1269,6 +1269,8 @@ github.com/liggitt/tabwriter v0.0.0-20181228230101-89fcab3d43de/go.mod h1:zAbeS9
 github.com/linuxkit/virtsock v0.0.0-20201010232012-f8cee7dfc7a3/go.mod h1:3r6x7q95whyfWQpmGZTu3gk3v2YkMi05HEzl7Tf7YEo=
 github.com/lithammer/dedent v1.1.0/go.mod h1:jrXYCQtgg0nJiN+StA2KgR7w6CiQNv9Fd/Z9BP0jIOc=
 github.com/lithammer/shortuuid/v3 v3.0.7/go.mod h1:vMk8ke37EmiewwolSO1NLW8vP4ZaKlRuDIi8tWWmAts=
+github.com/looplab/fsm v1.0.1 h1:OEW0ORrIx095N/6lgoGkFkotqH6s7vaFPsgjLAaF5QU=
+github.com/looplab/fsm v1.0.1/go.mod h1:PmD3fFvQEIsjMEfvZdrCDZ6y8VwKTwWNjlpEr6IKPO4=
 github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0 h1:6E+4a0GO5zZEnZ81pIr0yLvtUWk2if982qA3F3QD6H4=
 github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0/go.mod h1:zJYVVT2jmtg6P3p1VtQj7WsuWi/y4VnjVBn7F8KPB3I=
 github.com/magefile/mage v1.9.0/go.mod h1:z5UZb/iS3GoOSn0JgWuiw7dxlurVYTu+/jHXqQg881A=
diff --git a/internal/pkg/agent/application/upgrade/fsm.go b/internal/pkg/agent/application/upgrade/fsm.go
new file mode 100644
index 00000000000..4d8289baa70
--- /dev/null
+++ b/internal/pkg/agent/application/upgrade/fsm.go
@@ -0,0 +1,108 @@
+package upgrade
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/elastic/elastic-agent/pkg/core/logger"
+	"github.com/looplab/fsm"
+)
+
+const (
+	StateRequested   = "UPG_REQUESTED"
+	StateScheduled   = "UPG_SCHEDULED"
+	StateDownloading = "UPG_DOWNLOADING"
+	StateExtracting  = "UPG_EXTRACTING"
+	StateReplacing   = "UPG_REPLACING"
+	StateRestarting  = "UPG_RESTARTING"
+	StateWatching    = "UPG_WATCHING"
+	StateRollback    = "UPG_ROLLBACK"
+	StateCompleted   = "UPG_COMPLETED"
+	StateFailed      = "UPG_FAILED"
+
+	ActionSucceeded   = "succeeded"
+	ActionFailed      = "failed"
+	ActionScheduling  = "scheduling"
+	ActionRollingBack = "rolling_back"
+)
+
+type FSM struct {
+	m *fsm.FSM
+}
+
+type StateTransitionCallback func(oldState, newState, action string)
+
+// NewFSM models the following finite state machine for Elastic Agent upgrades:
+//
+//	UPG_REQUESTED
+//	├─ scheduling ─> UPG_SCHEDULED
+//	└─ succeeded ─> UPG_DOWNLOADING
+//	UPG_SCHEDULED
+//	├─ succeeded ─> UPG_DOWNLOADING
+//	└─ failed ─> UPG_FAILED
+//	UPG_DOWNLOADING
+//	├─ succeeded ─> UPG_EXTRACTING
+//	└─ failed ─> UPG_FAILED
+//	UPG_EXTRACTING
+//	├─ succeeded ─> UPG_REPLACING
+//	└─ failed ─> UPG_FAILED
+//	UPG_REPLACING
+//	├─ succeeded ─> UPG_RESTARTING
+//	└─ failed ─> UPG_FAILED
+//	UPG_RESTARTING
+//	├─ succeeded ─> UPG_WATCHING
+//	└─ failed ─> UPG_FAILED
+//	UPG_WATCHING
+//	├─ succeeded ─> UPG_COMPLETED
+//	├─ rolling_back ─> UPG_ROLLBACK
+//	└─ failed ─> UPG_FAILED
+//	UPG_ROLLBACK
+//	├─ succeeded ─> UPG_COMPLETED
+//	└─ failed ─> UPG_FAILED
+//
+// It accepts an onAction callback that will be called any time a transition from one
+// state to the next is performed.
+func NewFSM(log *logger.Logger, onTransition StateTransitionCallback) *FSM {
+	return &FSM{
+		m: fsm.NewFSM(
+			StateRequested,
+			fsm.Events{
+				{Name: ActionScheduling, Src: []string{StateRequested}, Dst: StateScheduled},
+				{Name: ActionSucceeded, Src: []string{StateRequested, StateScheduled}, Dst: StateDownloading},
+				{Name: ActionSucceeded, Src: []string{StateDownloading}, Dst: StateExtracting},
+				{Name: ActionSucceeded, Src: []string{StateExtracting}, Dst: StateReplacing},
+				{Name: ActionSucceeded, Src: []string{StateReplacing}, Dst: StateRestarting},
+				{Name: ActionSucceeded, Src: []string{StateRestarting}, Dst: StateWatching},
+				{Name: ActionSucceeded, Src: []string{StateWatching}, Dst: StateCompleted},
+				{Name: ActionRollingBack, Src: []string{StateWatching}, Dst: StateRollback},
+				{Name: ActionSucceeded, Src: []string{StateRollback}, Dst: StateCompleted},
+				{Name: ActionFailed, Src: []string{StateScheduled, StateDownloading, StateExtracting, StateReplacing, StateRestarting, StateWatching, StateRollback}, Dst: StateFailed},
+			},
+			fsm.Callbacks{
+				"enter_state": func(_ context.Context, e *fsm.Event) {
+					// Log state entry
+					log.Infow(
+						"transitioning upgrade state machine",
+						"from", e.Src, "to", e.Dst, "action", e.Event,
+					)
+
+					// Call onTransition
+					onTransition(e.Src, e.Dst, e.Event)
+				},
+			},
+		),
+	}
+}
+
+func (f *FSM) Transition(ctx context.Context, action string, args ...interface{}) error {
+	current := f.Current()
+	if err := f.m.Event(ctx, action, args...); err != nil {
+		return fmt.Errorf("unable to transition from [%s] with action [%s]: %w", current, action, err)
+	}
+
+	return nil
+}
+
+func (f *FSM) Current() string {
+	return f.m.Current()
+}
diff --git a/internal/pkg/agent/application/upgrade/fsm_test.go b/internal/pkg/agent/application/upgrade/fsm_test.go
new file mode 100644
index 00000000000..08860faa502
--- /dev/null
+++ b/internal/pkg/agent/application/upgrade/fsm_test.go
@@ -0,0 +1,42 @@
+package upgrade
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/elastic/elastic-agent/pkg/core/logger"
+)
+
+func TestFSM(t *testing.T) {
+	l, obs := logger.NewTesting("upgrade_fsm")
+	cb := func(oldState, newState, action string) {
+		// TODO
+	}
+
+	fsm := NewFSM(l, cb)
+
+	// Test that valid transition succeeds
+	err := fsm.Transition(context.Background(), ActionSucceeded)
+	require.NoError(t, err)
+	require.Equal(t, StateDownloading, fsm.Current())
+	require.Equal(t, 1, obs.Len())
+
+	log := obs.TakeAll()[0]
+	require.Equal(t, "transitioning upgrade state machine", log.Message)
+	require.Equal(t, "from", log.Context[0].Key)
+	require.Equal(t, StateRequested, log.Context[0].String)
+	require.Equal(t, "to", log.Context[1].Key)
+	require.Equal(t, StateDownloading, log.Context[1].String)
+
+	// Test that invalid transition returns error
+	err = fsm.Transition(context.Background(), ActionRollingBack)
+	require.Error(t, err)
+	require.EqualError(t, err, fmt.Sprintf(
+		"unable to transition from [%[1]s] with action [%[2]s]: event %[2]s inappropriate in current state %[1]s",
+		StateDownloading, ActionRollingBack,
+	))
+	require.Equal(t, 0, obs.Len())
+}

From 5682966e9e0ec240780c155bb7be1cec9189c0a8 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Mon, 2 Oct 2023 18:49:34 -0700
Subject: [PATCH 05/16] Implementing TODO

---
 internal/pkg/agent/application/upgrade/fsm.go |  7 +-
 .../pkg/agent/application/upgrade/fsm_test.go | 69 ++++++++++++++-----
 2 files changed, 59 insertions(+), 17 deletions(-)

diff --git a/internal/pkg/agent/application/upgrade/fsm.go b/internal/pkg/agent/application/upgrade/fsm.go
index 4d8289baa70..a5469cc893d 100644
--- a/internal/pkg/agent/application/upgrade/fsm.go
+++ b/internal/pkg/agent/application/upgrade/fsm.go
@@ -1,11 +1,16 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
 package upgrade
 
 import (
 	"context"
 	"fmt"
 
-	"github.com/elastic/elastic-agent/pkg/core/logger"
 	"github.com/looplab/fsm"
+
+	"github.com/elastic/elastic-agent/pkg/core/logger"
 )
 
 const (
diff --git a/internal/pkg/agent/application/upgrade/fsm_test.go b/internal/pkg/agent/application/upgrade/fsm_test.go
index 08860faa502..b116b022fb6 100644
--- a/internal/pkg/agent/application/upgrade/fsm_test.go
+++ b/internal/pkg/agent/application/upgrade/fsm_test.go
@@ -1,42 +1,79 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
 package upgrade
 
 import (
 	"context"
 	"fmt"
+	"sync/atomic"
 	"testing"
 
 	"github.com/stretchr/testify/require"
+	"go.uber.org/zap/zaptest/observer"
 
 	"github.com/elastic/elastic-agent/pkg/core/logger"
 )
 
 func TestFSM(t *testing.T) {
 	l, obs := logger.NewTesting("upgrade_fsm")
+
+	var cbCallCounter atomic.Int64
 	cb := func(oldState, newState, action string) {
-		// TODO
+		cbCallCounter.Add(1)
 	}
 
 	fsm := NewFSM(l, cb)
+	require.Equal(t, int64(0), cbCallCounter.Load())
+
+	// Test that valid transitions succeed
+	t.Run("valid_transition", func(t *testing.T) {
+		// UPG_REQUESTED ─── scheduling ───> UPG_SCHEDULED
+		err := fsm.Transition(context.Background(), ActionScheduling)
+		verifyValidTransition(t, fsm, obs, err, cbCallCounter.Load(), StateRequested, StateScheduled, 1)
+
+		// UPG_SCHEDULED ─── succeeded ───> UPG_DOWNLOADING
+		err = fsm.Transition(context.Background(), ActionSucceeded)
+		verifyValidTransition(t, fsm, obs, err, cbCallCounter.Load(), StateScheduled, StateDownloading, 2)
+
+		// UPG_DOWNLOADING ─── failed ───> UPG_FAILED
+		err = fsm.Transition(context.Background(), ActionFailed)
+		verifyValidTransition(t, fsm, obs, err, cbCallCounter.Load(), StateDownloading, StateFailed, 3)
+	})
+
+	// Test that an invalid transition returns error
+	t.Run("invalid_transition", func(t *testing.T) {
+		// UPG_FAILED ─── rolling_back ───> error
+		err := fsm.Transition(context.Background(), ActionRollingBack)
+		require.Error(t, err)
+		require.EqualError(t, err, fmt.Sprintf(
+			"unable to transition from [%[1]s] with action [%[2]s]: event %[2]s inappropriate in current state %[1]s",
+			StateFailed, ActionRollingBack,
+		))
+		require.Equal(t, int64(3), cbCallCounter.Load())
+		require.Equal(t, 0, obs.Len())
+	})
+}
+
+func verifyValidTransition(
+	t *testing.T,
+	upgradeFSM *FSM, obs *observer.ObservedLogs,
+	actualErr error, actualCBCallCounter int64,
+	expectedStartState, expectedEndState string,
+	expectedCBCallCounter int64,
+) {
+	t.Helper()
 
-	// Test that valid transition succeeds
-	err := fsm.Transition(context.Background(), ActionSucceeded)
-	require.NoError(t, err)
-	require.Equal(t, StateDownloading, fsm.Current())
+	require.NoError(t, actualErr)
+	require.Equal(t, expectedEndState, upgradeFSM.Current())
 	require.Equal(t, 1, obs.Len())
+	require.Equal(t, expectedCBCallCounter, actualCBCallCounter)
 
 	log := obs.TakeAll()[0]
 	require.Equal(t, "transitioning upgrade state machine", log.Message)
 	require.Equal(t, "from", log.Context[0].Key)
-	require.Equal(t, StateRequested, log.Context[0].String)
+	require.Equal(t, expectedStartState, log.Context[0].String)
 	require.Equal(t, "to", log.Context[1].Key)
-	require.Equal(t, StateDownloading, log.Context[1].String)
-
-	// Test that invalid transition returns error
-	err = fsm.Transition(context.Background(), ActionRollingBack)
-	require.Error(t, err)
-	require.EqualError(t, err, fmt.Sprintf(
-		"unable to transition from [%[1]s] with action [%[2]s]: event %[2]s inappropriate in current state %[1]s",
-		StateDownloading, ActionRollingBack,
-	))
-	require.Equal(t, 0, obs.Len())
+	require.Equal(t, expectedEndState, log.Context[1].String)
 }

From ba3e4f7b226d8c2171a7fc4507ed66c34cb0e52a Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Wed, 4 Oct 2023 05:41:18 -0700
Subject: [PATCH 06/16] WIP

---
 internal/pkg/agent/application/upgrade/fsm.go | 113 ------------------
 .../pkg/agent/application/upgrade/fsm_test.go |  79 ------------
 .../pkg/agent/application/upgrade/state.go    |  24 ++++
 .../application/upgrade/step_download.go      |   3 +-
 4 files changed, 25 insertions(+), 194 deletions(-)
 delete mode 100644 internal/pkg/agent/application/upgrade/fsm.go
 delete mode 100644 internal/pkg/agent/application/upgrade/fsm_test.go
 create mode 100644 internal/pkg/agent/application/upgrade/state.go

diff --git a/internal/pkg/agent/application/upgrade/fsm.go b/internal/pkg/agent/application/upgrade/fsm.go
deleted file mode 100644
index a5469cc893d..00000000000
--- a/internal/pkg/agent/application/upgrade/fsm.go
+++ /dev/null
@@ -1,113 +0,0 @@
-// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
-// or more contributor license agreements. Licensed under the Elastic License;
-// you may not use this file except in compliance with the Elastic License.
-
-package upgrade
-
-import (
-	"context"
-	"fmt"
-
-	"github.com/looplab/fsm"
-
-	"github.com/elastic/elastic-agent/pkg/core/logger"
-)
-
-const (
-	StateRequested   = "UPG_REQUESTED"
-	StateScheduled   = "UPG_SCHEDULED"
-	StateDownloading = "UPG_DOWNLOADING"
-	StateExtracting  = "UPG_EXTRACTING"
-	StateReplacing   = "UPG_REPLACING"
-	StateRestarting  = "UPG_RESTARTING"
-	StateWatching    = "UPG_WATCHING"
-	StateRollback    = "UPG_ROLLBACK"
-	StateCompleted   = "UPG_COMPLETED"
-	StateFailed      = "UPG_FAILED"
-
-	ActionSucceeded   = "succeeded"
-	ActionFailed      = "failed"
-	ActionScheduling  = "scheduling"
-	ActionRollingBack = "rolling_back"
-)
-
-type FSM struct {
-	m *fsm.FSM
-}
-
-type StateTransitionCallback func(oldState, newState, action string)
-
-// NewFSM models the following finite state machine for Elastic Agent upgrades:
-//
-//	UPG_REQUESTED
-//	├─ scheduling ─> UPG_SCHEDULED
-//	└─ succeeded ─> UPG_DOWNLOADING
-//	UPG_SCHEDULED
-//	├─ succeeded ─> UPG_DOWNLOADING
-//	└─ failed ─> UPG_FAILED
-//	UPG_DOWNLOADING
-//	├─ succeeded ─> UPG_EXTRACTING
-//	└─ failed ─> UPG_FAILED
-//	UPG_EXTRACTING
-//	├─ succeeded ─> UPG_REPLACING
-//	└─ failed ─> UPG_FAILED
-//	UPG_REPLACING
-//	├─ succeeded ─> UPG_RESTARTING
-//	└─ failed ─> UPG_FAILED
-//	UPG_RESTARTING
-//	├─ succeeded ─> UPG_WATCHING
-//	└─ failed ─> UPG_FAILED
-//	UPG_WATCHING
-//	├─ succeeded ─> UPG_COMPLETED
-//	├─ rolling_back ─> UPG_ROLLBACK
-//	└─ failed ─> UPG_FAILED
-//	UPG_ROLLBACK
-//	├─ succeeded ─> UPG_COMPLETED
-//	└─ failed ─> UPG_FAILED
-//
-// It accepts an onAction callback that will be called any time a transition from one
-// state to the next is performed.
-func NewFSM(log *logger.Logger, onTransition StateTransitionCallback) *FSM {
-	return &FSM{
-		m: fsm.NewFSM(
-			StateRequested,
-			fsm.Events{
-				{Name: ActionScheduling, Src: []string{StateRequested}, Dst: StateScheduled},
-				{Name: ActionSucceeded, Src: []string{StateRequested, StateScheduled}, Dst: StateDownloading},
-				{Name: ActionSucceeded, Src: []string{StateDownloading}, Dst: StateExtracting},
-				{Name: ActionSucceeded, Src: []string{StateExtracting}, Dst: StateReplacing},
-				{Name: ActionSucceeded, Src: []string{StateReplacing}, Dst: StateRestarting},
-				{Name: ActionSucceeded, Src: []string{StateRestarting}, Dst: StateWatching},
-				{Name: ActionSucceeded, Src: []string{StateWatching}, Dst: StateCompleted},
-				{Name: ActionRollingBack, Src: []string{StateWatching}, Dst: StateRollback},
-				{Name: ActionSucceeded, Src: []string{StateRollback}, Dst: StateCompleted},
-				{Name: ActionFailed, Src: []string{StateScheduled, StateDownloading, StateExtracting, StateReplacing, StateRestarting, StateWatching, StateRollback}, Dst: StateFailed},
-			},
-			fsm.Callbacks{
-				"enter_state": func(_ context.Context, e *fsm.Event) {
-					// Log state entry
-					log.Infow(
-						"transitioning upgrade state machine",
-						"from", e.Src, "to", e.Dst, "action", e.Event,
-					)
-
-					// Call onTransition
-					onTransition(e.Src, e.Dst, e.Event)
-				},
-			},
-		),
-	}
-}
-
-func (f *FSM) Transition(ctx context.Context, action string, args ...interface{}) error {
-	current := f.Current()
-	if err := f.m.Event(ctx, action, args...); err != nil {
-		return fmt.Errorf("unable to transition from [%s] with action [%s]: %w", current, action, err)
-	}
-
-	return nil
-}
-
-func (f *FSM) Current() string {
-	return f.m.Current()
-}
diff --git a/internal/pkg/agent/application/upgrade/fsm_test.go b/internal/pkg/agent/application/upgrade/fsm_test.go
deleted file mode 100644
index b116b022fb6..00000000000
--- a/internal/pkg/agent/application/upgrade/fsm_test.go
+++ /dev/null
@@ -1,79 +0,0 @@
-// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
-// or more contributor license agreements. Licensed under the Elastic License;
-// you may not use this file except in compliance with the Elastic License.
-
-package upgrade
-
-import (
-	"context"
-	"fmt"
-	"sync/atomic"
-	"testing"
-
-	"github.com/stretchr/testify/require"
-	"go.uber.org/zap/zaptest/observer"
-
-	"github.com/elastic/elastic-agent/pkg/core/logger"
-)
-
-func TestFSM(t *testing.T) {
-	l, obs := logger.NewTesting("upgrade_fsm")
-
-	var cbCallCounter atomic.Int64
-	cb := func(oldState, newState, action string) {
-		cbCallCounter.Add(1)
-	}
-
-	fsm := NewFSM(l, cb)
-	require.Equal(t, int64(0), cbCallCounter.Load())
-
-	// Test that valid transitions succeed
-	t.Run("valid_transition", func(t *testing.T) {
-		// UPG_REQUESTED ─── scheduling ───> UPG_SCHEDULED
-		err := fsm.Transition(context.Background(), ActionScheduling)
-		verifyValidTransition(t, fsm, obs, err, cbCallCounter.Load(), StateRequested, StateScheduled, 1)
-
-		// UPG_SCHEDULED ─── succeeded ───> UPG_DOWNLOADING
-		err = fsm.Transition(context.Background(), ActionSucceeded)
-		verifyValidTransition(t, fsm, obs, err, cbCallCounter.Load(), StateScheduled, StateDownloading, 2)
-
-		// UPG_DOWNLOADING ─── failed ───> UPG_FAILED
-		err = fsm.Transition(context.Background(), ActionFailed)
-		verifyValidTransition(t, fsm, obs, err, cbCallCounter.Load(), StateDownloading, StateFailed, 3)
-	})
-
-	// Test that an invalid transition returns error
-	t.Run("invalid_transition", func(t *testing.T) {
-		// UPG_FAILED ─── rolling_back ───> error
-		err := fsm.Transition(context.Background(), ActionRollingBack)
-		require.Error(t, err)
-		require.EqualError(t, err, fmt.Sprintf(
-			"unable to transition from [%[1]s] with action [%[2]s]: event %[2]s inappropriate in current state %[1]s",
-			StateFailed, ActionRollingBack,
-		))
-		require.Equal(t, int64(3), cbCallCounter.Load())
-		require.Equal(t, 0, obs.Len())
-	})
-}
-
-func verifyValidTransition(
-	t *testing.T,
-	upgradeFSM *FSM, obs *observer.ObservedLogs,
-	actualErr error, actualCBCallCounter int64,
-	expectedStartState, expectedEndState string,
-	expectedCBCallCounter int64,
-) {
-	t.Helper()
-
-	require.NoError(t, actualErr)
-	require.Equal(t, expectedEndState, upgradeFSM.Current())
-	require.Equal(t, 1, obs.Len())
-	require.Equal(t, expectedCBCallCounter, actualCBCallCounter)
-
-	log := obs.TakeAll()[0]
-	require.Equal(t, "transitioning upgrade state machine", log.Message)
-	require.Equal(t, "from", log.Context[0].Key)
-	require.Equal(t, expectedStartState, log.Context[0].String)
-	require.Equal(t, "to", log.Context[1].Key)
-	require.Equal(t, expectedEndState, log.Context[1].String)
-}
diff --git a/internal/pkg/agent/application/upgrade/state.go b/internal/pkg/agent/application/upgrade/state.go
new file mode 100644
index 00000000000..f21c4f799da
--- /dev/null
+++ b/internal/pkg/agent/application/upgrade/state.go
@@ -0,0 +1,24 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package upgrade
+
+type State string
+
+const (
+	StateRequested   State = "UPG_REQUESTED"
+	StateScheduled   State = "UPG_SCHEDULED"
+	StateDownloading State = "UPG_DOWNLOADING"
+	StateExtracting  State = "UPG_EXTRACTING"
+	StateReplacing   State = "UPG_REPLACING"
+	StateRestarting  State = "UPG_RESTARTING"
+	StateWatching    State = "UPG_WATCHING"
+	StateRollback    State = "UPG_ROLLBACK"
+	StateCompleted   State = "UPG_COMPLETED"
+	StateFailed      State = "UPG_FAILED"
+)
+
+func (s State) String() string {
+	return string(s)
+}
diff --git a/internal/pkg/agent/application/upgrade/step_download.go b/internal/pkg/agent/application/upgrade/step_download.go
index d86a43a5a3b..121a8e9cc26 100644
--- a/internal/pkg/agent/application/upgrade/step_download.go
+++ b/internal/pkg/agent/application/upgrade/step_download.go
@@ -12,8 +12,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
-
 	"github.com/cenkalti/backoff/v4"
 
 	"go.elastic.co/apm"
@@ -26,6 +24,7 @@ import (
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/artifact/download/http"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/artifact/download/localremote"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/artifact/download/snapshot"
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/errors"
 	"github.com/elastic/elastic-agent/internal/pkg/release"
 	"github.com/elastic/elastic-agent/pkg/core/logger"

From ff0a03804227f8aa95e4b64a22bb3500f5ebef41 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Wed, 4 Oct 2023 15:54:52 -0700
Subject: [PATCH 07/16] WIP

---
 .../handlers/handler_action_upgrade_test.go   |  2 ++
 .../application/coordinator/coordinator.go    |  3 ++-
 .../pkg/agent/application/upgrade/state.go    | 24 -------------------
 3 files changed, 4 insertions(+), 25 deletions(-)
 delete mode 100644 internal/pkg/agent/application/upgrade/state.go

diff --git a/internal/pkg/agent/application/actions/handlers/handler_action_upgrade_test.go b/internal/pkg/agent/application/actions/handlers/handler_action_upgrade_test.go
index b917b00b900..2dfc74519a0 100644
--- a/internal/pkg/agent/application/actions/handlers/handler_action_upgrade_test.go
+++ b/internal/pkg/agent/application/actions/handlers/handler_action_upgrade_test.go
@@ -9,6 +9,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
+
 	"github.com/stretchr/testify/require"
 
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/coordinator"
diff --git a/internal/pkg/agent/application/coordinator/coordinator.go b/internal/pkg/agent/application/coordinator/coordinator.go
index 778232b91d8..9d691a1c66b 100644
--- a/internal/pkg/agent/application/coordinator/coordinator.go
+++ b/internal/pkg/agent/application/coordinator/coordinator.go
@@ -10,6 +10,8 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
+
 	"github.com/hashicorp/go-multierror"
 
 	"go.elastic.co/apm"
@@ -20,7 +22,6 @@ import (
 
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/info"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/reexec"
-	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/configuration"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/transpiler"
 	"github.com/elastic/elastic-agent/internal/pkg/capabilities"
diff --git a/internal/pkg/agent/application/upgrade/state.go b/internal/pkg/agent/application/upgrade/state.go
deleted file mode 100644
index f21c4f799da..00000000000
--- a/internal/pkg/agent/application/upgrade/state.go
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
-// or more contributor license agreements. Licensed under the Elastic License;
-// you may not use this file except in compliance with the Elastic License.
-
-package upgrade
-
-type State string
-
-const (
-	StateRequested   State = "UPG_REQUESTED"
-	StateScheduled   State = "UPG_SCHEDULED"
-	StateDownloading State = "UPG_DOWNLOADING"
-	StateExtracting  State = "UPG_EXTRACTING"
-	StateReplacing   State = "UPG_REPLACING"
-	StateRestarting  State = "UPG_RESTARTING"
-	StateWatching    State = "UPG_WATCHING"
-	StateRollback    State = "UPG_ROLLBACK"
-	StateCompleted   State = "UPG_COMPLETED"
-	StateFailed      State = "UPG_FAILED"
-)
-
-func (s State) String() string {
-	return string(s)
-}

From 1730cd91445c40cd7f783fb5aee6d181fff72b8d Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Wed, 4 Oct 2023 15:56:53 -0700
Subject: [PATCH 08/16] Reorganizing imports

---
 .../actions/handlers/handler_action_upgrade_test.go            | 2 --
 internal/pkg/agent/application/coordinator/coordinator.go      | 3 +--
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/internal/pkg/agent/application/actions/handlers/handler_action_upgrade_test.go b/internal/pkg/agent/application/actions/handlers/handler_action_upgrade_test.go
index 2dfc74519a0..b917b00b900 100644
--- a/internal/pkg/agent/application/actions/handlers/handler_action_upgrade_test.go
+++ b/internal/pkg/agent/application/actions/handlers/handler_action_upgrade_test.go
@@ -9,8 +9,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
-
 	"github.com/stretchr/testify/require"
 
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/coordinator"
diff --git a/internal/pkg/agent/application/coordinator/coordinator.go b/internal/pkg/agent/application/coordinator/coordinator.go
index 9d691a1c66b..778232b91d8 100644
--- a/internal/pkg/agent/application/coordinator/coordinator.go
+++ b/internal/pkg/agent/application/coordinator/coordinator.go
@@ -10,8 +10,6 @@ import (
 	"fmt"
 	"time"
 
-	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
-
 	"github.com/hashicorp/go-multierror"
 
 	"go.elastic.co/apm"
@@ -22,6 +20,7 @@ import (
 
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/info"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/reexec"
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/configuration"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/transpiler"
 	"github.com/elastic/elastic-agent/internal/pkg/capabilities"

From 3cd9f84d7064922e7bca81f702f991ddc80cf401 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Wed, 4 Oct 2023 15:59:48 -0700
Subject: [PATCH 09/16] Running go mod tidy

---
 go.mod | 1 -
 go.sum | 2 --
 2 files changed, 3 deletions(-)

diff --git a/go.mod b/go.mod
index fa00c749819..847bf6d35c5 100644
--- a/go.mod
+++ b/go.mod
@@ -35,7 +35,6 @@ require (
 	github.com/joeshaw/multierror v0.0.0-20140124173710-69b34d4ec901
 	github.com/josephspurrier/goversioninfo v0.0.0-20190209210621-63e6d1acd3dd
 	github.com/kardianos/service v1.2.1-0.20210728001519-a323c3813bc7
-	github.com/looplab/fsm v1.0.1
 	github.com/magefile/mage v1.15.0
 	github.com/mitchellh/gox v1.0.1
 	github.com/mitchellh/hashstructure v1.1.0
diff --git a/go.sum b/go.sum
index c6d2633bfea..708ac86b4fc 100644
--- a/go.sum
+++ b/go.sum
@@ -1269,8 +1269,6 @@ github.com/liggitt/tabwriter v0.0.0-20181228230101-89fcab3d43de/go.mod h1:zAbeS9
 github.com/linuxkit/virtsock v0.0.0-20201010232012-f8cee7dfc7a3/go.mod h1:3r6x7q95whyfWQpmGZTu3gk3v2YkMi05HEzl7Tf7YEo=
 github.com/lithammer/dedent v1.1.0/go.mod h1:jrXYCQtgg0nJiN+StA2KgR7w6CiQNv9Fd/Z9BP0jIOc=
 github.com/lithammer/shortuuid/v3 v3.0.7/go.mod h1:vMk8ke37EmiewwolSO1NLW8vP4ZaKlRuDIi8tWWmAts=
-github.com/looplab/fsm v1.0.1 h1:OEW0ORrIx095N/6lgoGkFkotqH6s7vaFPsgjLAaF5QU=
-github.com/looplab/fsm v1.0.1/go.mod h1:PmD3fFvQEIsjMEfvZdrCDZ6y8VwKTwWNjlpEr6IKPO4=
 github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0 h1:6E+4a0GO5zZEnZ81pIr0yLvtUWk2if982qA3F3QD6H4=
 github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0/go.mod h1:zJYVVT2jmtg6P3p1VtQj7WsuWi/y4VnjVBn7F8KPB3I=
 github.com/magefile/mage v1.9.0/go.mod h1:z5UZb/iS3GoOSn0JgWuiw7dxlurVYTu+/jHXqQg881A=

From b1f368f4765f62411a9acf1c428139333044b8c2 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Fri, 13 Oct 2023 05:48:47 -0700
Subject: [PATCH 10/16] Fixing booboos introduced during conflict resolution

---
 .../upgrade/artifact/download/http/progress_reporter.go         | 2 --
 1 file changed, 2 deletions(-)

diff --git a/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go b/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
index 2df81be6018..491646b3ab5 100644
--- a/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
+++ b/internal/pkg/agent/application/upgrade/artifact/download/http/progress_reporter.go
@@ -70,8 +70,6 @@ func (dp *downloadProgressReporter) Report(ctx context.Context) {
 				return
 			case <-dp.done:
 				return
-			case <-dp.done:
-				return
 			case <-t.C:
 				now := time.Now()
 				timePast := now.Sub(started)

From f98765d491f5da6e3737f94dd33cccde0491c29f Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Tue, 17 Oct 2023 14:03:58 -0700
Subject: [PATCH 11/16] Add nil guard

---
 internal/pkg/agent/application/coordinator/coordinator.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/internal/pkg/agent/application/coordinator/coordinator.go b/internal/pkg/agent/application/coordinator/coordinator.go
index 778232b91d8..d4338f9cca6 100644
--- a/internal/pkg/agent/application/coordinator/coordinator.go
+++ b/internal/pkg/agent/application/coordinator/coordinator.go
@@ -490,6 +490,9 @@ func (c *Coordinator) Upgrade(ctx context.Context, version string, sourceURI str
 }
 
 func (c *Coordinator) logUpgradeDetails(details *details.Details) {
+	if details == nil {
+		return
+	}
 	c.logger.Infow("updated upgrade details", "upgrade_details", details)
 }
 

From 2f864f079b252ae8d8692e7a99e5693ef57d978b Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Tue, 17 Oct 2023 14:21:42 -0700
Subject: [PATCH 12/16] Setting logger in test

---
 internal/pkg/agent/application/coordinator/coordinator.go | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/internal/pkg/agent/application/coordinator/coordinator.go b/internal/pkg/agent/application/coordinator/coordinator.go
index d4338f9cca6..778232b91d8 100644
--- a/internal/pkg/agent/application/coordinator/coordinator.go
+++ b/internal/pkg/agent/application/coordinator/coordinator.go
@@ -490,9 +490,6 @@ func (c *Coordinator) Upgrade(ctx context.Context, version string, sourceURI str
 }
 
 func (c *Coordinator) logUpgradeDetails(details *details.Details) {
-	if details == nil {
-		return
-	}
 	c.logger.Infow("updated upgrade details", "upgrade_details", details)
 }
 

From f7dbb2d0cca9168c248088539ab1b86dc15a58b1 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Tue, 17 Oct 2023 17:19:51 -0700
Subject: [PATCH 13/16] Include upgrade details in diagnostics bundle

---
 .../application/coordinator/coordinator.go    | 26 ++++++++++---------
 .../application/upgrade/details/details.go    | 18 ++++++-------
 2 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/internal/pkg/agent/application/coordinator/coordinator.go b/internal/pkg/agent/application/coordinator/coordinator.go
index 778232b91d8..4604313fb04 100644
--- a/internal/pkg/agent/application/coordinator/coordinator.go
+++ b/internal/pkg/agent/application/coordinator/coordinator.go
@@ -791,12 +791,13 @@ func (c *Coordinator) DiagnosticHooks() diagnostics.Hooks {
 					State runtime.ComponentState `yaml:"state"`
 				}
 				type StateHookOutput struct {
-					State        agentclient.State      `yaml:"state"`
-					Message      string                 `yaml:"message"`
-					FleetState   agentclient.State      `yaml:"fleet_state"`
-					FleetMessage string                 `yaml:"fleet_message"`
-					LogLevel     logp.Level             `yaml:"log_level"`
-					Components   []StateComponentOutput `yaml:"components"`
+					State          agentclient.State      `yaml:"state"`
+					Message        string                 `yaml:"message"`
+					FleetState     agentclient.State      `yaml:"fleet_state"`
+					FleetMessage   string                 `yaml:"fleet_message"`
+					LogLevel       logp.Level             `yaml:"log_level"`
+					Components     []StateComponentOutput `yaml:"components"`
+					UpgradeDetails *details.Details       `yaml:"upgrade_details,omitempty"`
 				}
 
 				s := c.State()
@@ -809,12 +810,13 @@ func (c *Coordinator) DiagnosticHooks() diagnostics.Hooks {
 					}
 				}
 				output := StateHookOutput{
-					State:        s.State,
-					Message:      s.Message,
-					FleetState:   s.FleetState,
-					FleetMessage: s.FleetMessage,
-					LogLevel:     s.LogLevel,
-					Components:   compStates,
+					State:          s.State,
+					Message:        s.Message,
+					FleetState:     s.FleetState,
+					FleetMessage:   s.FleetMessage,
+					LogLevel:       s.LogLevel,
+					Components:     compStates,
+					UpgradeDetails: s.UpgradeDetails,
 				}
 				o, err := yaml.Marshal(output)
 				if err != nil {
diff --git a/internal/pkg/agent/application/upgrade/details/details.go b/internal/pkg/agent/application/upgrade/details/details.go
index 028990aafcd..5dd9ce1d7a3 100644
--- a/internal/pkg/agent/application/upgrade/details/details.go
+++ b/internal/pkg/agent/application/upgrade/details/details.go
@@ -24,10 +24,10 @@ type Observer func(details *Details)
 
 // Details consists of details regarding an ongoing upgrade.
 type Details struct {
-	TargetVersion string   `json:"target_version"`
-	State         State    `json:"state"`
-	ActionID      string   `json:"action_id,omitempty"`
-	Metadata      Metadata `json:"metadata"`
+	TargetVersion string   `json:"target_version" yaml:"target_version"`
+	State         State    `json:"state" yaml:"state"`
+	ActionID      string   `json:"action_id,omitempty" yaml:"action_id,omitempty"`
+	Metadata      Metadata `json:"metadata" yaml:"metadata"`
 
 	observers []Observer
 	mu        sync.Mutex
@@ -35,19 +35,19 @@ type Details struct {
 
 // Metadata consists of metadata relating to a specific upgrade state
 type Metadata struct {
-	ScheduledAt     time.Time    `json:"scheduled_at,omitempty"`
-	DownloadPercent float64      `json:"download_percent,omitempty"`
-	DownloadRate    downloadRate `json:"download_rate,omitempty"`
+	ScheduledAt     time.Time    `json:"scheduled_at,omitempty" yaml:"scheduled_at,omitempty"`
+	DownloadPercent float64      `json:"download_percent,omitempty" yaml:"download_percent,omitempty"`
+	DownloadRate    downloadRate `json:"download_rate,omitempty" yaml:"download_rate,omitempty"`
 
 	// FailedState is the state an upgrade was in if/when it failed. Use the
 	// Fail() method of UpgradeDetails to correctly record details when
 	// an upgrade fails.
-	FailedState State `json:"failed_state,omitempty"`
+	FailedState State `json:"failed_state,omitempty" yaml:"failed_state,omitempty"`
 
 	// ErrorMsg is any error message encountered if/when an upgrade fails. Use
 	// the Fail() method of UpgradeDetails to correctly record details when
 	// an upgrade fails.
-	ErrorMsg string `json:"error_msg,omitempty"`
+	ErrorMsg string `json:"error_msg,omitempty" yaml:"error_msg,omitempty"`
 }
 
 func NewDetails(targetVersion string, initialState State, actionID string) *Details {

From cba774df3ef85aca794cc34fc73ac195c7712718 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Tue, 17 Oct 2023 17:23:56 -0700
Subject: [PATCH 14/16] Adding CHANGELOG entry

---
 ...588586-upgrade-details-in-diagnostics.yaml | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 changelog/fragments/1697588586-upgrade-details-in-diagnostics.yaml

diff --git a/changelog/fragments/1697588586-upgrade-details-in-diagnostics.yaml b/changelog/fragments/1697588586-upgrade-details-in-diagnostics.yaml
new file mode 100644
index 00000000000..ed415252d53
--- /dev/null
+++ b/changelog/fragments/1697588586-upgrade-details-in-diagnostics.yaml
@@ -0,0 +1,32 @@
+# Kind can be one of:
+# - breaking-change: a change to previously-documented behavior
+# - deprecation: functionality that is being removed in a later release
+# - bug-fix: fixes a problem in a previous version
+# - enhancement: extends functionality but does not break or fix existing behavior
+# - feature: new functionality
+# - known-issue: problems that we are aware of in a given version
+# - security: impacts on the security of a product or a user’s deployment.
+# - upgrade: important information for someone upgrading from a prior version
+# - other: does not fit into any of the other categories
+kind: enhancement
+
+# Change summary; a 80ish characters long description of the change.
+summary: Include upgrade details in diagnostics bundle.
+
+# Long description; in case the summary is not enough to describe the change
+# this field accommodate a description without length limits.
+# NOTE: This field will be rendered only for breaking-change and known-issue kinds at the moment.
+#description:
+
+# Affected component; usually one of "elastic-agent", "fleet-server", "filebeat", "metricbeat", "auditbeat", "all", etc.
+component: elastic-agent
+
+# PR URL; optional; the PR number that added the changeset.
+# If not present is automatically filled by the tooling finding the PR where this changelog fragment has been added.
+# NOTE: the tooling supports backports, so it's able to fill the original PR number instead of the backport PR number.
+# Please provide it if you are adding a fragment for a different PR.
+pr: https://github.com/elastic/elastic-agent/pull/3624
+
+# Issue URL; optional; the GitHub issue related to this changeset (either closes or is part of).
+# If not present is automatically filled by the tooling with the issue linked to the PR number.
+#issue: https://github.com/owner/repo/1234

From f93d5e24092fc95b307d7150da4ae32923b00984 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Wed, 1 Nov 2023 11:42:52 +0530
Subject: [PATCH 15/16] Add unit test

---
 .../coordinator/diagnostics_test.go           | 29 ++++++++++++++++---
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/internal/pkg/agent/application/coordinator/diagnostics_test.go b/internal/pkg/agent/application/coordinator/diagnostics_test.go
index c6f2dc4fc97..9fec8e1844b 100644
--- a/internal/pkg/agent/application/coordinator/diagnostics_test.go
+++ b/internal/pkg/agent/application/coordinator/diagnostics_test.go
@@ -7,16 +7,18 @@ package coordinator
 import (
 	"context"
 	"errors"
+	"fmt"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
 
-	"github.com/elastic/elastic-agent-client/v7/pkg/proto"
-
 	"github.com/elastic/elastic-agent-client/v7/pkg/client"
+	"github.com/elastic/elastic-agent-client/v7/pkg/proto"
 
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/details"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/configuration"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/transpiler"
 	monitoringCfg "github.com/elastic/elastic-agent/internal/pkg/core/monitoring/config"
@@ -413,6 +415,7 @@ func TestDiagnosticState(t *testing.T) {
 	// Create a coordinator with a test state and verify that the state
 	// diagnostic reports it
 
+	now := time.Now().UTC()
 	state := State{
 		State:        agentclient.Starting,
 		Message:      "starting up",
@@ -432,9 +435,19 @@ func TestDiagnosticState(t *testing.T) {
 				},
 			},
 		},
+		UpgradeDetails: &details.Details{
+			TargetVersion: "8.12.0",
+			State:         "UPG_DOWNLOADING",
+			ActionID:      "foobar",
+			Metadata: details.Metadata{
+				DownloadPercent: 0.17469,
+				ScheduledAt:     now,
+				DownloadRate:    123.56,
+			},
+		},
 	}
 
-	expected := `
+	expected := fmt.Sprintf(`
 state: 0
 message: "starting up"
 fleet_state: 1
@@ -451,7 +464,15 @@ components:
       version_info:
         name: "version name"
         version: "version value"
-`
+upgrade_details:
+  target_version: 8.12.0
+  state: UPG_DOWNLOADING
+  action_id: foobar
+  metadata:
+    download_percent: 0.17469
+    scheduled_at: %s
+    download_rate: 123.56
+`, now.Format(time.RFC3339Nano))
 
 	coord := &Coordinator{
 		// This test needs a broadcaster since the components-actual diagnostic

From a8aed84a70aef2551185ec65f0d7ad07c413da63 Mon Sep 17 00:00:00 2001
From: Shaunak Kashyap <ycombinator@gmail.com>
Date: Wed, 1 Nov 2023 11:42:57 +0530
Subject: [PATCH 16/16] Add godoc

---
 .../agent/application/upgrade/details/details.go   | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/internal/pkg/agent/application/upgrade/details/details.go b/internal/pkg/agent/application/upgrade/details/details.go
index 5dd9ce1d7a3..a4cb9954d4b 100644
--- a/internal/pkg/agent/application/upgrade/details/details.go
+++ b/internal/pkg/agent/application/upgrade/details/details.go
@@ -35,9 +35,15 @@ type Details struct {
 
 // Metadata consists of metadata relating to a specific upgrade state
 type Metadata struct {
-	ScheduledAt     time.Time    `json:"scheduled_at,omitempty" yaml:"scheduled_at,omitempty"`
-	DownloadPercent float64      `json:"download_percent,omitempty" yaml:"download_percent,omitempty"`
-	DownloadRate    downloadRate `json:"download_rate,omitempty" yaml:"download_rate,omitempty"`
+	ScheduledAt time.Time `json:"scheduled_at,omitempty" yaml:"scheduled_at,omitempty"`
+
+	// DownloadPercent is the percentage of the artifact that has been
+	// downloaded. Minimum value is 0 and maximum value is 1.
+	DownloadPercent float64 `json:"download_percent,omitempty" yaml:"download_percent,omitempty"`
+
+	// DownloadRate is the rate, in bytes per second, at which the download
+	// is progressing.
+	DownloadRate downloadRate `json:"download_rate,omitempty" yaml:"download_rate,omitempty"`
 
 	// FailedState is the state an upgrade was in if/when it failed. Use the
 	// Fail() method of UpgradeDetails to correctly record details when
@@ -71,7 +77,7 @@ func (d *Details) SetState(s State) {
 }
 
 // SetDownloadProgress is a convenience method to set the download percent
-// when the upgrade is in UPG_DOWNLOADING state.
+// and download rate when the upgrade is in UPG_DOWNLOADING state.
 func (d *Details) SetDownloadProgress(percent, rateBytesPerSecond float64) {
 	d.mu.Lock()
 	defer d.mu.Unlock()