Graceful: Cancel Process on monitor pages & HammerTime (#9213)

* Graceful: Create callbacks to with contexts

* Graceful: Say when Gitea is completely finished

* Graceful: Git and Process within HammerTime

Force all git commands to terminate at HammerTime
Force all process commands to terminate at HammerTime
Move almost all git processes to run as git Commands

* Graceful: Always Hammer after Shutdown

* ProcessManager: Add cancel functionality

* Fix tests

* Make sure that process.Manager.Kill() cancels

* Make threadsafe access to Processes and remove own unused Kill

* Remove cmd from the process manager as it is no longer used

* the default context is the correct context

* get rid of double till

3 files changed, 44 insertions, 11 deletions

diff --git a/modules/git/blame.go b/modules/git/blame.go
index 4f4343fe96..5a9ae9a74f 100644
--- a/modules/git/blame.go
+++ b/modules/git/blame.go
@@ -6,6 +6,7 @@ package git
 
 import (
 	"bufio"
+	"context"
 	"fmt"
 	"io"
 	"os"
@@ -28,6 +29,7 @@ type BlameReader struct {
 	output  io.ReadCloser
 	scanner *bufio.Scanner
 	lastSha *string
+	cancel  context.CancelFunc
 }
 
 var shaLineRegex = regexp.MustCompile("^([a-z0-9]{40})")
@@ -76,7 +78,8 @@ func (r *BlameReader) NextPart() (*BlamePart, error) {
 
 // Close BlameReader - don't run NextPart after invoking that
 func (r *BlameReader) Close() error {
-	process.GetManager().Remove(r.pid)
+	defer process.GetManager().Remove(r.pid)
+	defer r.cancel()
 
 	if err := r.cmd.Wait(); err != nil {
 		return fmt.Errorf("Wait: %v", err)
@@ -97,20 +100,24 @@ func CreateBlameReader(repoPath, commitID, file string) (*BlameReader, error) {
 }
 
 func createBlameReader(dir string, command ...string) (*BlameReader, error) {
-	cmd := exec.Command(command[0], command[1:]...)
+	// FIXME: graceful: This should have a timeout
+	ctx, cancel := context.WithCancel(DefaultContext)
+	cmd := exec.CommandContext(ctx, command[0], command[1:]...)
 	cmd.Dir = dir
 	cmd.Stderr = os.Stderr
 
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
+		defer cancel()
 		return nil, fmt.Errorf("StdoutPipe: %v", err)
 	}
 
 	if err = cmd.Start(); err != nil {
+		defer cancel()
 		return nil, fmt.Errorf("Start: %v", err)
 	}
 
-	pid := process.GetManager().Add(fmt.Sprintf("GetBlame [repo_path: %s]", dir), cmd)
+	pid := process.GetManager().Add(fmt.Sprintf("GetBlame [repo_path: %s]", dir), cancel)
 
 	scanner := bufio.NewScanner(stdout)
 
@@ -120,5 +127,6 @@ func createBlameReader(dir string, command ...string) (*BlameReader, error) {
 		stdout,
 		scanner,
 		nil,
+		cancel,
 	}, nil
 }
diff --git a/modules/git/command.go b/modules/git/command.go
index 65878edb7d..f01db2e1d8 100644
--- a/modules/git/command.go
+++ b/modules/git/command.go
@@ -30,8 +30,10 @@ const DefaultLocale = "C"
 
 // Command represents a command with its subcommands or arguments.
 type Command struct {
-	name string
-	args []string
+	name          string
+	args          []string
+	parentContext context.Context
+	desc          string
 }
 
 func (c *Command) String() string {
@@ -47,19 +49,34 @@ func NewCommand(args ...string) *Command {
 	cargs := make([]string, len(GlobalCommandArgs))
 	copy(cargs, GlobalCommandArgs)
 	return &Command{
-		name: GitExecutable,
-		args: append(cargs, args...),
+		name:          GitExecutable,
+		args:          append(cargs, args...),
+		parentContext: DefaultContext,
 	}
 }
 
 // NewCommandNoGlobals creates and returns a new Git Command based on given command and arguments only with the specify args and don't care global command args
 func NewCommandNoGlobals(args ...string) *Command {
 	return &Command{
-		name: GitExecutable,
-		args: args,
+		name:          GitExecutable,
+		args:          args,
+		parentContext: DefaultContext,
 	}
 }
 
+// SetParentContext sets the parent context for this command
+func (c *Command) SetParentContext(ctx context.Context) *Command {
+	c.parentContext = ctx
+	return c
+}
+
+// SetDescription sets the description for this command which be returned on
+// c.String()
+func (c *Command) SetDescription(desc string) *Command {
+	c.desc = desc
+	return c
+}
+
 // AddArguments adds new argument(s) to the command.
 func (c *Command) AddArguments(args ...string) *Command {
 	c.args = append(c.args, args...)
@@ -92,7 +109,7 @@ func (c *Command) RunInDirTimeoutEnvFullPipelineFunc(env []string, timeout time.
 		log("%s: %v", dir, c)
 	}
 
-	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	ctx, cancel := context.WithTimeout(c.parentContext, timeout)
 	defer cancel()
 
 	cmd := exec.CommandContext(ctx, c.name, c.args...)
@@ -110,7 +127,11 @@ func (c *Command) RunInDirTimeoutEnvFullPipelineFunc(env []string, timeout time.
 		return err
 	}
 
-	pid := process.GetManager().Add(fmt.Sprintf("%s %s %s [repo_path: %s]", GitExecutable, c.name, strings.Join(c.args, " "), dir), cmd)
+	desc := c.desc
+	if desc == "" {
+		desc = fmt.Sprintf("%s %s %s [repo_path: %s]", GitExecutable, c.name, strings.Join(c.args, " "), dir)
+	}
+	pid := process.GetManager().Add(desc, cancel)
 	defer process.GetManager().Remove(pid)
 
 	if fn != nil {
diff --git a/modules/git/git.go b/modules/git/git.go
index df50eac72a..286e1ad8b4 100644
--- a/modules/git/git.go
+++ b/modules/git/git.go
@@ -6,6 +6,7 @@
 package git
 
 import (
+	"context"
 	"fmt"
 	"os/exec"
 	"runtime"
@@ -35,6 +36,9 @@ var (
 	// Could be updated to an absolute path while initialization
 	GitExecutable = "git"
 
+	// DefaultContext is the default context to run git commands in
+	DefaultContext = context.Background()
+
 	gitVersion string
 )