Add support to define a custom docker network and enable docker ipv6 (#893)

- Add support to define a custom docker network and enable docker ipv6
- Adjust docs

docs/docs/30-administration/15-agent-config.md

@@ -155,6 +155,10 @@ Configures if the gRPC server certificate should be verified, only valid when `W
 
 Configures the backend engine to run pipelines on. Possible values are `auto-detect`, `docker`, `local` or `ssh`.
 
+### `WOODPECKER_BACKEND_DOCKER_*`
+
+See [Docker backend configuration](backends/docker/#configuration)
+
 ### `WOODPECKER_BACKEND_SSH_*`
 
 See [SSH backend configuration](backends/ssh/#configuration)

docs/docs/30-administration/22-backends/10-docker.md

@@ -1 +1,15 @@
 # Docker backend
+
+This is the original backend used with Woodpecker. The docker backend executes each step inside a separate container started on the agent.
+
+## Configuration
+
+### `WOODPECKER_BACKEND_DOCKER_NETWORK`
+> Default: empty
+
+Set to the name of an existing network which will be attached to all your pipeline containers (steps). Please be careful as this allows the containers of different piplines to access each other!
+
+### `WOODPECKER_BACKEND_DOCKER_ENABLE_IPV6`
+> Default: `false`
+
+Enable IPv6 for the networks used by pipeline containers (steps). Make sure you configured your docker daemon to support IPv6.

docs/docs/40-cli.md

@@ -254,37 +254,37 @@ execute a local build
 
 **--build-created**="":  (default: 0)
 
-**--build-event**="": 
+**--build-event**="":
 
 **--build-finished**="":  (default: 0)
 
-**--build-link**="": 
+**--build-link**="":
 
 **--build-number**="":  (default: 0)
 
 **--build-started**="":  (default: 0)
 
-**--build-status**="": 
+**--build-status**="":
 
-**--build-target**="": 
+**--build-target**="":
 
-**--commit-author-avatar**="": 
+**--commit-author-avatar**="":
 
-**--commit-author-email**="": 
+**--commit-author-email**="":
 
-**--commit-author-name**="": 
+**--commit-author-name**="":
 
-**--commit-branch**="": 
+**--commit-branch**="":
 
-**--commit-message**="": 
+**--commit-message**="":
 
-**--commit-ref**="": 
+**--commit-ref**="":
 
-**--commit-refspec**="": 
+**--commit-refspec**="":
 
-**--commit-sha**="": 
+**--commit-sha**="":
 
-**--env**="": 
+**--env**="":
 
 **--job-number**="":  (default: 0)
 
@@ -292,11 +292,11 @@ execute a local build
 
 **--log-level**="": set logging level (default: info)
 
-**--netrc-machine**="": 
+**--netrc-machine**="":
 
-**--netrc-password**="": 
+**--netrc-password**="":
 
-**--netrc-username**="": 
+**--netrc-username**="":
 
 **--network**="": external networks
 
@@ -304,43 +304,43 @@ execute a local build
 
 **--prev-build-created**="":  (default: 0)
 
-**--prev-build-event**="": 
+**--prev-build-event**="":
 
 **--prev-build-finished**="":  (default: 0)
 
-**--prev-build-link**="": 
+**--prev-build-link**="":
 
 **--prev-build-number**="":  (default: 0)
 
 **--prev-build-started**="":  (default: 0)
 
-**--prev-build-status**="": 
+**--prev-build-status**="":
 
-**--prev-commit-author-avatar**="": 
+**--prev-commit-author-avatar**="":
 
-**--prev-commit-author-email**="": 
+**--prev-commit-author-email**="":
 
-**--prev-commit-author-name**="": 
+**--prev-commit-author-name**="":
 
-**--prev-commit-branch**="": 
+**--prev-commit-branch**="":
 
-**--prev-commit-message**="": 
+**--prev-commit-message**="":
 
-**--prev-commit-ref**="": 
+**--prev-commit-ref**="":
 
-**--prev-commit-refspec**="": 
+**--prev-commit-refspec**="":
 
-**--prev-commit-sha**="": 
+**--prev-commit-sha**="":
 
 **--privileged**="": privileged plugins (default: [plugins/docker plugins/gcr plugins/ecr woodpeckerci/plugin-docker woodpeckerci/plugin-docker-buildx])
 
-**--repo-link**="": 
+**--repo-link**="":
 
-**--repo-name**="": 
+**--repo-name**="":
 
-**--repo-private**="": 
+**--repo-private**="":
 
-**--repo-remote-url**="": 
+**--repo-remote-url**="":
 
 **--server, -s**="": server address
 

pipeline/backend/docker/docker.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"io"
 	"os"
+	"strconv"
 	"strings"
 
 	"github.com/docker/docker/api/types"
@@ -19,7 +20,9 @@ import (
 )
 
 type docker struct {
-	client client.APIClient
+	client     client.APIClient
+	enableIPv6 bool
+	network    string
 }
 
 // make sure docker implements Engine
@@ -52,6 +55,10 @@ func (e *docker) Load() error {
 	}
 	e.client = cli
 
+	e.enableIPv6, _ = strconv.ParseBool(os.Getenv("WOODPECKER_BACKEND_DOCKER_ENABLE_IPV6"))
+
+	e.network = os.Getenv("WOODPECKER_BACKEND_DOCKER_NETWORK")
+
 	return nil
 }
 
@@ -69,8 +76,9 @@ func (e *docker) Setup(_ context.Context, conf *backend.Config) error {
 	}
 	for _, n := range conf.Networks {
 		_, err := e.client.NetworkCreate(noContext, n.Name, types.NetworkCreate{
-			Driver:  n.Driver,
-			Options: n.DriverOpts,
+			Driver:     n.Driver,
+			Options:    n.DriverOpts,
+			EnableIPv6: e.enableIPv6,
 			// Labels:  defaultLabels,
 		})
 		if err != nil {
@@ -137,16 +145,15 @@ func (e *docker) Exec(ctx context.Context, proc *backend.Step) error {
 				return err
 			}
 		}
-	}
 
-	// if proc.Network != "host" { // or bridge, overlay, none, internal, container:<name> ....
-	// 	err = e.client.NetworkConnect(ctx, proc.Network, proc.Name, &network.EndpointSettings{
-	// 		Aliases: proc.NetworkAliases,
-	// 	})
-	// 	if err != nil {
-	// 		return err
-	// 	}
-	// }
+		// join the container to an existing network
+		if e.network != "" {
+			err = e.client.NetworkConnect(ctx, e.network, proc.Name, &network.EndpointSettings{})
+			if err != nil {
+				return err
+			}
+		}
+	}
 
 	return e.client.ContainerStart(ctx, proc.Name, startOpts)
 }