Add support for SignalTask. (#64)

* Add support for SignalTask.

Signed-off-by: Shishir Mahajan <smahajan@roblox.com>

client.go

@@ -30,6 +30,7 @@ import (
 	"os"
 	"os/user"
 	"strings"
+	"syscall"
 	"time"
 )
 
@@ -109,6 +110,17 @@ func (c *PodmanClient) StopContainer(containerID string, timeoutSeconds int64) e
 	return err
 }
 
+// Forward signal to the container.
+// This is an optional capability.
+func (c *PodmanClient) SignalContainer(containerID string, sig os.Signal) error {
+	c.logger.Debug("Sending signal to the container", "container", containerID, "signal", sig)
+	err := c.withVarlink(func(varlinkConnection *varlink.Connection) error {
+		_, err := iopodman.KillContainer().Call(c.ctx, varlinkConnection, containerID, int64(sig.(syscall.Signal)))
+		return err
+	})
+	return err
+}
+
 // ForceRemoveContainer requires the name or ID of a container and will stop and remove a container and it's volumes.
 // iI container cannot be found by name or ID, a [ContainerNotFound](#ContainerNotFound) error will be returned.
 func (c *PodmanClient) ForceRemoveContainer(containerID string) error {

driver.go

@@ -19,6 +19,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"github.com/hashicorp/consul-template/signals"
 	"os/user"
 	"path/filepath"
 	"strings"
@@ -65,7 +66,7 @@ var (
 	// capabilities is returned by the Capabilities RPC and indicates what
 	// optional features this driver supports
 	capabilities = &drivers.Capabilities{
-		SendSignals: false,
+		SendSignals: true,
 		Exec:        false,
 		FSIsolation: drivers.FSIsolationNone,
 		NetIsolationModes: []drivers.NetIsolationMode{
@@ -668,7 +669,20 @@ func (d *Driver) TaskEvents(ctx context.Context) (<-chan *drivers.TaskEvent, err
 // SignalTask function is used by drivers which support sending OS signals (SIGHUP, SIGKILL, SIGUSR1 etc.) to the task.
 // It is an optional function and is listed as a capability in the driver Capabilities struct.
 func (d *Driver) SignalTask(taskID string, signal string) error {
-	return fmt.Errorf("Podman driver does not support signals")
+	handle, ok := d.tasks.Get(taskID)
+	if !ok {
+		return drivers.ErrTaskNotFound
+	}
+
+	// The given signal will be forwarded to the target taskID.
+	// Please checkout https://github.com/hashicorp/consul-template/blob/master/signals/signals_unix.go
+	// for a list of supported signals.
+	sig, ok := signals.SignalLookup[signal]
+	if !ok {
+		return fmt.Errorf("Invalid signal: %s", signal)
+	}
+
+	return d.podmanClient.SignalContainer(handle.containerID, sig)
 }
 
 // ExecTask function is used by the Nomad client to execute commands inside the task execution context.

go.mod

@@ -19,6 +19,7 @@ require (
 	github.com/docker/go-metrics v0.0.1 // indirect
 	github.com/go-ole/go-ole v1.2.4 // indirect
 	github.com/hashicorp/consul v1.7.3 // indirect
+	github.com/hashicorp/consul-template v0.24.1
 	github.com/hashicorp/go-hclog v0.14.1
 	github.com/hashicorp/nomad v0.11.3-0.20200630133459-42c2ee4448c8
 	github.com/hashicorp/nomad/api v0.0.0-20200630133459-42c2ee4448c8
@@ -28,5 +29,6 @@ require (
 	github.com/stretchr/testify v1.5.1
 	github.com/varlink/go v0.3.0
 	google.golang.org/grpc v1.29.1 // indirect
+	gotest.tools/gotestsum v0.5.2 // indirect
 
 )

go.sum

@@ -316,6 +316,8 @@ github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXi
 github.com/google/pprof v0.0.0-20181206194817-3ea8567a2e57/go.mod h1:zfwlbNMJ+OItoe0UupaVj+oy1omPYYDuagoSzA8v9mc=
 github.com/google/pprof v0.0.0-20190515194954-54271f7e092f/go.mod h1:zfwlbNMJ+OItoe0UupaVj+oy1omPYYDuagoSzA8v9mc=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
+github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
+github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
 github.com/googleapis/gax-go v2.0.0+incompatible h1:j0GKcs05QVmm7yesiZq2+9cxHkNK9YM6zKx4D2qucQU=
 github.com/googleapis/gax-go v2.0.0+incompatible/go.mod h1:SFVmujtThgffbyetf+mdk2eWhX2bMyUtNHzFKcPA9HY=
 github.com/googleapis/gax-go/v2 v2.0.3/go.mod h1:LLvjysVCY1JZeum8Z6l8qUty8fiNwE08qbEPm1M08qg=
@@ -499,6 +501,8 @@ github.com/jmespath/go-jmespath v0.0.0-20160202185014-0b12d6b521d8/go.mod h1:Nht
 github.com/jmespath/go-jmespath v0.0.0-20160803190731-bd40a432e4c7/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
 github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af h1:pmfjZENx5imkbgOkpRUYLnmbU7UEFbjtDA2hxJ1ichM=
 github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
+github.com/jonboulle/clockwork v0.1.0 h1:VKV+ZcuP6l3yW9doeqz6ziZGgcynBVQO+obU0+0hcPo=
+github.com/jonboulle/clockwork v0.1.0/go.mod h1:Ii8DK3G1RaLaWxj9trq07+26W01tbo22gdxWY5EU2bo=
 github.com/joyent/triton-go v0.0.0-20180628001255-830d2b111e62/go.mod h1:U+RSyWxWd04xTqnuOQxnai7XGS2PrPY2cfGoDKtMHjA=
 github.com/joyent/triton-go v0.0.0-20190112182421-51ffac552869 h1:BvV6PYcRz0yGnWXNZrd5wginNT1GfFfPvvWpPbjfFL8=
 github.com/joyent/triton-go v0.0.0-20190112182421-51ffac552869/go.mod h1:U+RSyWxWd04xTqnuOQxnai7XGS2PrPY2cfGoDKtMHjA=
@@ -991,6 +995,7 @@ golang.org/x/sys v0.0.0-20200124204421-9fbb57f87de9/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae h1:/WDfKMnPU+m5M4xB+6x4kaepxRw6jWvR5iDRdvjHgy8=
 golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200515095857-1151b9dac4a9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200523222454-059865788121 h1:rITEj+UZHYC927n8GT97eC3zrpzXdb/voyeOuVKS46o=
 golang.org/x/sys v0.0.0-20200523222454-059865788121/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -1127,8 +1132,11 @@ gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gotest.tools v1.4.0 h1:BjtEgfuw8Qyd+jPvQz8CfoxiO/UjFEidWinwEXZiWv0=
 gotest.tools v2.2.0+incompatible h1:VsBPFP1AI068pPrMxtb/S8Zkgf9xEmTLJjfM+P5UIEo=
 gotest.tools v2.2.0+incompatible/go.mod h1:DsYFclhRJ6vuDpmuTbkuFWG+y2sxOXAzmJt81HFBacw=
+gotest.tools/gotestsum v0.5.2 h1:sSKWtEFqorHhuBCHU6MeUl50cq9U2J3d1m5NlQTVrbY=
+gotest.tools/gotestsum v0.5.2/go.mod h1:hC9TQserDVTWcJuARh76Ydp3ZwuE+pIIWpt2BzDLD6M=
 gotest.tools/v3 v3.0.2 h1:kG1BFyqVHuQoVQiR1bWGnfz/fmHvvuiSPIV7rvl360E=
 gotest.tools/v3 v3.0.2/go.mod h1:3SzNCllyD9/Y+b5r9JIKQ474KzkZyqLqEfYqMsX94Bk=
 grpc.go4.org v0.0.0-20170609214715-11d0a25b4919/go.mod h1:77eQGdRu53HpSqPFJFmuJdjuHRquDANNeA4x7B8WQ9o=