Add support for Builder arbitrary build commands

Reviewers: thcipriani, dduvall, #release-engineering-team

Reviewed By: dduvall, #release-engineering-team

Tags: #release-engineering-team

Differential Revision: https://phabricator.wikimedia.org/D1054

4 files changed, 102 insertions, 9 deletions

diff --git a/blubber.example.yaml b/blubber.example.yaml
index e4fe3c9..80eddc3 100644
--- a/blubber.example.yaml
+++ b/blubber.example.yaml
@@ -18,6 +18,7 @@ variants:
       dependencies: true
     python:
       requirements: [requirements.txt]
+    builder: [make, -f, Makefile]
 
   development:
     includes: [build]
diff --git a/config/builder.go b/config/builder.go
new file mode 100644
index 0000000..112f181
--- /dev/null
+++ b/config/builder.go
@@ -0,0 +1,47 @@
+package config
+
+import (
+	"phabricator.wikimedia.org/source/blubber/build"
+)
+
+// BuilderConfig contains configuration for the definition of an arbitrary
+// build command.
+//
+type BuilderConfig struct {
+	Builder []string `yaml:"builder"`
+}
+
+// Merge takes another BuilderConfig and merges its fields into this one's,
+// overwriting the builder command.
+//
+func (bc *BuilderConfig) Merge(bc2 BuilderConfig) {
+	if len(bc2.Builder) > 0 {
+		bc.Builder = bc2.Builder
+	}
+}
+
+// InstructionsForPhase injects instructions into the build related to
+// builder commands.
+//
+// PhasePostInstall
+//
+// Runs build command provided for the builder
+//
+func (bc BuilderConfig) InstructionsForPhase(phase build.Phase) []build.Instruction {
+	switch phase {
+	case build.PhasePostInstall:
+		if len(bc.Builder) == 0 {
+			return []build.Instruction{}
+		}
+
+		run := build.Run{Command: bc.Builder[0]}
+
+		if len(bc.Builder) > 1 {
+			run.Arguments = bc.Builder[1:]
+		}
+
+		return []build.Instruction{run}
+	}
+
+	return []build.Instruction{}
+}
diff --git a/config/builder_test.go b/config/builder_test.go
new file mode 100644
index 0000000..dbc95d9
--- /dev/null
+++ b/config/builder_test.go
@@ -0,0 +1,43 @@
+package config_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"phabricator.wikimedia.org/source/blubber/build"
+	"phabricator.wikimedia.org/source/blubber/config"
+)
+
+func TestBuilderConfigYAML(t *testing.T) {
+	cfg, err := config.ReadConfig([]byte(`---
+    version: v1
+    base: foo
+    variants:
+      build:
+        builder: [make, -f, Makefile]`))
+
+	if assert.NoError(t, err) {
+		variant, err := config.ExpandVariant(cfg, "build")
+
+		assert.Equal(t, []string{"make", "-f", "Makefile"}, variant.Builder)
+
+		assert.Nil(t, err)
+	}
+}
+
+func TestBuilderConfigInstructions(t *testing.T) {
+	cfg := config.BuilderConfig{Builder: []string{"make", "-f", "Makefile"}}
+
+	t.Run("PhasePostInstall", func(t *testing.T) {
+		assert.Equal(t,
+			[]build.Instruction{
+				build.Run{
+					"make",
+					[]string{"-f", "Makefile"},
+				},
+			},
+			cfg.InstructionsForPhase(build.PhasePostInstall),
+		)
+	})
+}
diff --git a/config/common.go b/config/common.go
index 4cc300d..96fb2b0 100644
--- a/config/common.go
+++ b/config/common.go
@@ -8,14 +8,15 @@ import (
 // and each configured variant.
 //
 type CommonConfig struct {
-	Base         string       `yaml:"base" validate:"omitempty,baseimage"` // name/path to base image
-	Apt          AptConfig    `yaml:"apt"`                                 // APT related
-	Node         NodeConfig   `yaml:"node"`                                // Node related
-	Python       PythonConfig `yaml:"python"`                              // Python related
-	Lives        LivesConfig  `yaml:"lives"`                               // application owner/dir
-	Runs         RunsConfig   `yaml:"runs"`                                // runtime environment
-	SharedVolume Flag         `yaml:"sharedvolume"`                        // use volume for app
-	EntryPoint   []string     `yaml:"entrypoint"`                          // entry-point executable
+	Base          string           `yaml:"base" validate:"omitempty,baseimage"` // name/path to base image
+	Apt           AptConfig        `yaml:"apt"`                                 // APT related
+	Node          NodeConfig       `yaml:"node"`                                // Node related
+	Python        PythonConfig     `yaml:"python"`                              // Python related
+	BuilderConfig `yaml:",inline"` // Builder related
+	Lives         LivesConfig      `yaml:"lives"`        // application owner/dir
+	Runs          RunsConfig       `yaml:"runs"`         // runtime environment
+	SharedVolume  Flag             `yaml:"sharedvolume"` // use volume for app
+	EntryPoint    []string         `yaml:"entrypoint"`   // entry-point executable
 }
 
 // Merge takes another CommonConfig and merges its fields this one's.
@@ -28,6 +29,7 @@ func (cc *CommonConfig) Merge(cc2 CommonConfig) {
 	cc.Apt.Merge(cc2.Apt)
 	cc.Node.Merge(cc2.Node)
 	cc.Python.Merge(cc2.Python)
+	cc.BuilderConfig.Merge(cc2.BuilderConfig)
 	cc.Lives.Merge(cc2.Lives)
 	cc.Runs.Merge(cc2.Runs)
 	cc.SharedVolume.Merge(cc2.SharedVolume)
@@ -42,7 +44,7 @@ func (cc *CommonConfig) Merge(cc2 CommonConfig) {
 // injected.
 //
 func (cc *CommonConfig) PhaseCompileableConfig() []build.PhaseCompileable {
-	return []build.PhaseCompileable{cc.Apt, cc.Node, cc.Python, cc.Lives, cc.Runs}
+	return []build.PhaseCompileable{cc.Apt, cc.Node, cc.Python, cc.BuilderConfig, cc.Lives, cc.Runs}
 }
 
 // InstructionsForPhase injects instructions into the given build phase for