Support plugin-only secrets (#1344)

Closes #1071

pipeline/frontend/yaml/compiler/compiler_test.go

@@ -0,0 +1,42 @@
+package compiler
+
+import (
+	"testing"
+
+	"github.com/docker/docker/api/types/strslice"
+	"github.com/stretchr/testify/assert"
+	"github.com/woodpecker-ci/woodpecker/pipeline/frontend/yaml"
+	"github.com/woodpecker-ci/woodpecker/pipeline/frontend/yaml/types"
+)
+
+func TestSecretAvailable(t *testing.T) {
+	secret := Secret{
+		Match:      []string{"golang"},
+		PluginOnly: false,
+	}
+	assert.True(t, secret.Available(&yaml.Container{
+		Image:    "golang",
+		Commands: types.Stringorslice(strslice.StrSlice{"echo 'this is not a plugin'"}),
+	}))
+	assert.False(t, secret.Available(&yaml.Container{
+		Image:    "not-golang",
+		Commands: types.Stringorslice(strslice.StrSlice{"echo 'this is not a plugin'"}),
+	}))
+	// secret only available for "golang" plugin
+	secret = Secret{
+		Match:      []string{"golang"},
+		PluginOnly: true,
+	}
+	assert.True(t, secret.Available(&yaml.Container{
+		Image:    "golang",
+		Commands: types.Stringorslice(strslice.StrSlice{}),
+	}))
+	assert.False(t, secret.Available(&yaml.Container{
+		Image:    "not-golang",
+		Commands: types.Stringorslice(strslice.StrSlice{}),
+	}))
+	assert.False(t, secret.Available(&yaml.Container{
+		Image:    "not-golang",
+		Commands: types.Stringorslice(strslice.StrSlice{"echo 'this is not a plugin'"}),
+	}))
+}