Add Tailscale unstable channel and repo HEAD to integration tests

Dockerfile.tailscale

@@ -1,11 +1,12 @@
 FROM ubuntu:latest
 
 ARG TAILSCALE_VERSION
+ARG TAILSCALE_CHANNEL
 
 RUN apt-get update \
     && apt-get install -y gnupg curl \
-    && curl -fsSL https://pkgs.tailscale.com/stable/ubuntu/focal.gpg | apt-key add - \
-    && curl -fsSL https://pkgs.tailscale.com/stable/ubuntu/focal.list | tee /etc/apt/sources.list.d/tailscale.list \
+    && curl -fsSL https://pkgs.tailscale.com/${TAILSCALE_CHANNEL}/ubuntu/focal.gpg | apt-key add - \
+    && curl -fsSL https://pkgs.tailscale.com/${TAILSCALE_CHANNEL}/ubuntu/focal.list | tee /etc/apt/sources.list.d/tailscale.list \
     && apt-get update \
     && apt-get install -y ca-certificates tailscale=${TAILSCALE_VERSION} dnsutils \
     && rm -rf /var/lib/apt/lists/*

Dockerfile.tailscale-HEAD

@@ -0,0 +1,21 @@
+FROM golang:latest
+
+RUN apt-get update \
+    && apt-get install -y ca-certificates dnsutils git \
+    && rm -rf /var/lib/apt/lists/*
+
+
+RUN git clone https://github.com/tailscale/tailscale.git
+
+WORKDIR tailscale
+
+RUN sh build_dist.sh tailscale.com/cmd/tailscale
+RUN sh build_dist.sh tailscale.com/cmd/tailscaled
+
+RUN cp tailscale /usr/local/bin/
+RUN cp tailscaled /usr/local/bin/
+
+ADD integration_test/etc_embedded_derp/tls/server.crt /usr/local/share/ca-certificates/
+RUN chmod 644 /usr/local/share/ca-certificates/server.crt 
+
+RUN update-ca-certificates

integration_common_test.go

@@ -20,7 +20,7 @@ var (
 	IpPrefix4 = netaddr.MustParseIPPrefix("100.64.0.0/10")
 	IpPrefix6 = netaddr.MustParseIPPrefix("fd7a:115c:a1e0::/48")
 
-	tailscaleVersions = []string{"1.22.0", "1.20.4", "1.18.2", "1.16.2", "1.14.3", "1.12.3"}
+	tailscaleVersions = []string{"HEAD", "unstable", "1.22.0", "1.20.4", "1.18.2", "1.16.2", "1.14.3", "1.12.3"}
 )
 
 type TestNamespace struct {
@@ -128,6 +128,49 @@ func DockerAllowNetworkAdministration(config *docker.HostConfig) {
 	})
 }
 
+func getDockerBuildOptions(version string) *dockertest.BuildOptions {
+	var tailscaleBuildOptions *dockertest.BuildOptions
+	switch version {
+	case "HEAD":
+		tailscaleBuildOptions = &dockertest.BuildOptions{
+			Dockerfile: "Dockerfile.tailscale-HEAD",
+			ContextDir: ".",
+			BuildArgs:  []docker.BuildArg{},
+		}
+	case "unstable":
+		tailscaleBuildOptions = &dockertest.BuildOptions{
+			Dockerfile: "Dockerfile.tailscale",
+			ContextDir: ".",
+			BuildArgs: []docker.BuildArg{
+				{
+					Name:  "TAILSCALE_VERSION",
+					Value: "*", // Installs the latest version https://askubuntu.com/a/824926
+				},
+				{
+					Name:  "TAILSCALE_CHANNEL",
+					Value: "unstable",
+				},
+			},
+		}
+	default:
+		tailscaleBuildOptions = &dockertest.BuildOptions{
+			Dockerfile: "Dockerfile.tailscale",
+			ContextDir: ".",
+			BuildArgs: []docker.BuildArg{
+				{
+					Name:  "TAILSCALE_VERSION",
+					Value: version,
+				},
+				{
+					Name:  "TAILSCALE_CHANNEL",
+					Value: "stable",
+				},
+			},
+		}
+	}
+	return tailscaleBuildOptions
+}
+
 func getIPs(
 	tailscales map[string]dockertest.Resource,
 ) (map[string][]netaddr.IP, error) {

integration_embedded_derp_test.go

@@ -245,16 +245,8 @@ func (s *IntegrationDERPTestSuite) Join(
 
 func (s *IntegrationDERPTestSuite) tailscaleContainer(identifier, version string, network dockertest.Network,
 ) (string, *dockertest.Resource) {
-	tailscaleBuildOptions := &dockertest.BuildOptions{
-		Dockerfile: "Dockerfile.tailscale",
-		ContextDir: ".",
-		BuildArgs: []docker.BuildArg{
-			{
-				Name:  "TAILSCALE_VERSION",
-				Value: version,
-			},
-		},
-	}
+	tailscaleBuildOptions := getDockerBuildOptions(version)
+
 	hostname := fmt.Sprintf(
 		"tailscale-%s-%s",
 		strings.Replace(version, ".", "-", -1),

integration_test.go

@@ -168,16 +168,8 @@ func (s *IntegrationTestSuite) Join(
 func (s *IntegrationTestSuite) tailscaleContainer(
 	namespace, identifier, version string,
 ) (string, *dockertest.Resource) {
-	tailscaleBuildOptions := &dockertest.BuildOptions{
-		Dockerfile: "Dockerfile.tailscale",
-		ContextDir: ".",
-		BuildArgs: []docker.BuildArg{
-			{
-				Name:  "TAILSCALE_VERSION",
-				Value: version,
-			},
-		},
-	}
+	tailscaleBuildOptions := getDockerBuildOptions(version)
+
 	hostname := fmt.Sprintf(
 		"%s-tailscale-%s-%s",
 		namespace,