wip: stub structs and logic for a bundle workflow

* resolve a dependency graph
* identify the order of execution
* still working on how to represent a workflow of bundles to execute in a way that we can abstract with a driver

Signed-off-by: Carolyn Van Slyck <[email protected]>

go.mod

@@ -60,6 +60,7 @@ require (
 	github.com/spf13/viper v1.8.1
 	github.com/stretchr/testify v1.7.1
 	github.com/xeipuuv/gojsonschema v1.2.0
+	github.com/yourbasic/graph v0.0.0-20210606180040-8ecfec1c2869
 	go.mongodb.org/mongo-driver v1.7.1
 	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.29.0
 	go.opentelemetry.io/otel v1.7.0

go.sum

@@ -1578,6 +1578,8 @@ github.com/xi2/xz v0.0.0-20171230120015-48954b6210f8/go.mod h1:HUYIGzjTL3rfEspMx
 github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2/go.mod h1:UETIi67q53MR2AWcXfiuqkDkRtnGDLqkBTpCHuJHxtU=
 github.com/youmark/pkcs8 v0.0.0-20181117223130-1be2e3e5546d h1:splanxYIlg+5LfHAM6xpdFEAYOk8iySO56hMFq6uLyA=
 github.com/youmark/pkcs8 v0.0.0-20181117223130-1be2e3e5546d/go.mod h1:rHwXgn7JulP+udvsHwJoVG1YGAP6VLg4y9I5dyZdqmA=
+github.com/yourbasic/graph v0.0.0-20210606180040-8ecfec1c2869 h1:7v7L5lsfw4w8iqBBXETukHo4IPltmD+mWoLRYUmeGN8=
+github.com/yourbasic/graph v0.0.0-20210606180040-8ecfec1c2869/go.mod h1:Rfzr+sqaDreiCaoQbFCu3sTXxeFq/9kXRuyOoSlGQHE=
 github.com/yuin/goldmark v1.1.25/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.1.32/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=

pkg/workflow/bundle_graph.go

@@ -0,0 +1,234 @@
+package workflow
+
+import (
+	"context"
+
+	"get.porter.sh/porter/pkg/cnab"
+	"get.porter.sh/porter/pkg/storage"
+	"get.porter.sh/porter/pkg/tracing"
+	"github.com/Masterminds/semver/v3"
+	"github.com/cnabio/cnab-go/bundle"
+	"github.com/yourbasic/graph"
+	"go.opentelemetry.io/otel/attribute"
+)
+
+type BundleGraph struct {
+	// map[node.key]nodeIndex
+	nodeKeys map[string]int
+	nodes    []Node
+	// (DependencyV1 (unresolved), Bundle, Installation)
+}
+
+func NewBundleGraph() *BundleGraph {
+	return &BundleGraph{
+		nodeKeys: make(map[string]int),
+	}
+}
+
+// RegisterNode adds the specified node to the graph
+// returning true if the node is already present.
+func (g *BundleGraph) RegisterNode(node Node) bool {
+	_, exists := g.nodeKeys[node.GetKey()]
+	if !exists {
+		nodeIndex := len(g.nodes)
+		g.nodes = append(g.nodes, node)
+		g.nodeKeys[node.GetKey()] = nodeIndex
+	}
+	return exists
+}
+
+func (g *BundleGraph) Sort() ([]Node, bool) {
+	dag := graph.New(len(g.nodes))
+	for nodeIndex, node := range g.nodes {
+		for _, depKey := range node.GetRequires() {
+			depIndex, ok := g.nodeKeys[depKey]
+			if !ok {
+				panic("oops")
+			}
+			dag.Add(nodeIndex, depIndex)
+		}
+	}
+
+	indices, ok := graph.TopSort(dag)
+	if !ok {
+		return nil, false
+	}
+
+	// Reverse the sort so that items with no dependencies are listed first
+	count := len(indices)
+	results := make([]Node, count)
+	for i, nodeIndex := range indices {
+		results[count-i-1] = g.nodes[nodeIndex]
+	}
+	return results, true
+}
+
+func (g *BundleGraph) GetNode(key string) (Node, bool) {
+	if nodeIndex, ok := g.nodeKeys[key]; ok {
+		return g.nodes[nodeIndex], true
+	}
+	return nil, false
+}
+
+type Node interface {
+	GetRequires() []string
+	GetKey() string
+}
+
+var _ Node = BundleNode{}
+var _ Node = InstallationNode{}
+
+type BundleNode struct {
+	Key       string
+	Reference cnab.BundleReference
+	Requires  []string // TODO: we don't need to know this while resolving, find a less confusing way of storing this so it's clear who should set it
+}
+
+func (d BundleNode) GetKey() string {
+	return d.Key
+}
+
+func (d BundleNode) GetRequires() []string {
+	return d.Requires
+}
+
+type InstallationNode struct {
+	Key       string
+	Namespace string
+	Name      string
+}
+
+func (d InstallationNode) GetKey() string {
+	return d.Key
+}
+
+func (d InstallationNode) GetRequires() []string {
+	return nil
+}
+
+type Dependency struct {
+	Key                  string
+	DefaultBundle        *BundleReferenceSelector
+	Interface            *BundleInterfaceSelector
+	InstallationSelector *InstallationSelector
+	Requires             []string
+}
+
+type BundleReferenceSelector struct {
+	Reference cnab.OCIReference
+	Version   *semver.Constraints
+}
+
+func (s *BundleReferenceSelector) IsMatch(ctx context.Context, inst storage.Installation) bool {
+	log := tracing.LoggerFromContext(ctx)
+	log.Debug("Evaluating installation bundle definition")
+
+	if inst.Status.BundleReference == "" {
+		log.Debug("Installation does not match because it does not have an associated bundle")
+		return false
+	}
+
+	ref, err := cnab.ParseOCIReference(inst.Status.BundleReference)
+	if err != nil {
+		log.Warn("Could not evaluate installation because the BundleReference is invalid",
+			attribute.String("reference", inst.Status.BundleReference))
+		return false
+	}
+
+	// If no selector is defined, consider it a match
+	if s == nil {
+		return true
+	}
+
+	// If a version range is specified, ignore the version on the selector and apply the range
+	// otherwise match the tag or digest
+	if s.Version != nil {
+		if inst.Status.BundleVersion == "" {
+			log.Debug("Installation does not match because it does not have an associated bundle version")
+			return false
+		}
+
+		// First check that the repository is the same
+		gotRepo := ref.Repository()
+		wantRepo := s.Reference.Repository()
+		if gotRepo != wantRepo {
+			log.Warn("Installation does not match because the bundle repository is incorrect",
+				attribute.String("installation-bundle-repository", gotRepo),
+				attribute.String("dependency-bundle-repository", wantRepo),
+			)
+			return false
+		}
+
+		gotVersion, err := semver.NewVersion(inst.Status.BundleVersion)
+		if err != nil {
+			log.Warn("Installation does not match because the bundle version is invalid",
+				attribute.String("installation-bundle-version", inst.Status.BundleVersion),
+			)
+			return false
+		}
+
+		if s.Version.Check(gotVersion) {
+			log.Debug("Installation matches because the bundle version is in range",
+				attribute.String("installation-bundle-version", inst.Status.BundleVersion),
+				attribute.String("dependency-bundle-version", s.Version.String()),
+			)
+			return true
+		} else {
+			log.Debug("Installation does not match because the bundle version is incorrect",
+				attribute.String("installation-bundle-version", inst.Status.BundleVersion),
+				attribute.String("dependency-bundle-version", s.Version.String()),
+			)
+			return false
+		}
+	} else {
+		gotRef := ref.String()
+		wantRef := s.Reference.String()
+		if gotRef == wantRef {
+			log.Warn("Installation matches because the bundle reference is correct",
+				attribute.String("installation-bundle-reference", gotRef),
+				attribute.String("dependency-bundle-reference", wantRef),
+			)
+			return true
+		} else {
+			log.Warn("Installation does not match because the bundle reference is incorrect",
+				attribute.String("installation-bundle-reference", gotRef),
+				attribute.String("dependency-bundle-reference", wantRef),
+			)
+			return false
+		}
+	}
+}
+
+type InstallationSelector struct {
+	Bundle     *BundleReferenceSelector
+	Interface  *BundleInterfaceSelector
+	Labels     map[string]string
+	Namespaces []string
+}
+
+func (s InstallationSelector) IsMatch(ctx context.Context, inst storage.Installation) bool {
+	// Skip checking labels and namespaces, those were used to query the set of
+	// installations that we are checking
+
+	bundleMatches := s.Bundle.IsMatch(ctx, inst)
+	if !bundleMatches {
+		return false
+	}
+
+	interfaceMatches := s.Interface.IsMatch(ctx, inst)
+	return interfaceMatches
+}
+
+// BundleInterfaceSelector defines how a bundle is going to be used.
+// It is not the same as the bundle definition.
+// It works like go interfaces where its defined by its consumer.
+type BundleInterfaceSelector struct {
+	Parameters  []bundle.Parameter
+	Credentials []bundle.Credential
+	Outputs     []bundle.Output
+}
+
+func (s BundleInterfaceSelector) IsMatch(ctx context.Context, inst storage.Installation) bool {
+	// TODO: implement
+	return true
+}

pkg/workflow/bundle_graph_test.go

@@ -0,0 +1,70 @@
+package workflow
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestEngine_DependOnInstallation(t *testing.T) {
+	/*
+		A -> B (installation)
+		A -> C (bundle)
+		c.parameters.connstr <- B.outputs.connstr
+	*/
+
+	b := InstallationNode{Key: "b"}
+	c := BundleNode{
+		Key:      "c",
+		Requires: []string{"b"},
+	}
+	a := BundleNode{
+		Key:      "root",
+		Requires: []string{"b", "c"},
+	}
+
+	g := NewBundleGraph()
+	g.RegisterNode(a)
+	g.RegisterNode(b)
+	g.RegisterNode(c)
+	sortedNodes, ok := g.Sort()
+	require.True(t, ok, "graph should not be cyclic")
+
+	gotOrder := make([]string, len(sortedNodes))
+	for i, node := range sortedNodes {
+		gotOrder[i] = node.GetKey()
+	}
+	wantOrder := []string{
+		"b",
+		"c",
+		"root",
+	}
+	assert.Equal(t, wantOrder, gotOrder)
+}
+
+/*
+✅ need to represent new dependency structure on an extended bundle wrapper
+(put in cnab-go later)
+
+need to read a bundle and make a BundleGraph
+? how to handle a param that isn't a pure assignment, e.g. connstr: ${bundle.deps.VM.outputs.ip}:${bundle.deps.SVC.outputs.port}
+? when are templates evaluated as the graph is executed (for simplicity, first draft no composition / templating)
+
+need to resolve dependencies in the graph
+* lookup against existing installations
+* lookup against semver tags in registry
+* lookup against bundle index? when would we look here? (i.e. preferred/registered implementations of interfaces)
+
+need to turn the sorted nodes into an execution plan
+execution plan needs:
+* bundle to execute and the installation it will become
+* parameters and credentials to pass
+  * sources:
+ 	root parameters/creds
+	installation outputs
+
+need to write something that can run an execution plan
+* knows how to grab sources and pass them into the bundle
+*/

pkg/workflow/default_bundle_resolver.go

@@ -0,0 +1,38 @@
+package workflow
+
+import (
+	"context"
+
+	"get.porter.sh/porter/pkg/porter"
+)
+
+var _ DependencyResolver = DefaultBundleResolver{}
+
+// DefaultBundleResolver resolves the default bundle defined on the dependency.
+type DefaultBundleResolver struct {
+	puller porter.BundleResolver
+}
+
+func (d DefaultBundleResolver) Resolve(ctx context.Context, dep Dependency) (Node, bool, error) {
+	if dep.DefaultBundle == nil {
+		return nil, false, nil
+	}
+
+	pullOpts := porter.BundlePullOptions{
+		Reference: dep.DefaultBundle.Reference.String(),
+		// todo: respect force pull and insecure registry
+	}
+	if err := pullOpts.Validate(); err != nil {
+		return nil, false, err
+	}
+	cb, err := d.puller.Resolve(ctx, pullOpts)
+	if err != nil {
+		// wrap not found error and indicate that we could resolve anything
+		return nil, false, err
+	}
+
+	return BundleNode{
+		Key:       dep.Key,
+		Reference: cb.BundleReference,
+	}, true, nil
+}