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Merge pull request #199 from chrisdoherty4/feat/dynamically-build-sta…
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,20 @@ | ||
| package staticroute | ||
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| // unorderedSet is a utility data structure that behaves as a traditional unorderedSet. Its elements are unordered. | ||
| type unorderedSet map[string]struct{} | ||
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| func newUnorderedSet() unorderedSet { | ||
| return make(unorderedSet) | ||
| } | ||
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| // Insert adds v to s. | ||
| func (s unorderedSet) Insert(v string) { | ||
| s[v] = struct{}{} | ||
| } | ||
|
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| // Range iterates over the elements in s and calls fn for each element. | ||
| func (s unorderedSet) Range(fn func(v string)) { | ||
| for k := range s { | ||
| fn(k) | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,9 @@ | ||
| package staticroute | ||
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| type sortableRoutes []Route | ||
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| func (r sortableRoutes) Len() int { return len(r) } | ||
| func (r sortableRoutes) Swap(i, j int) { r[i], r[j] = r[j], r[i] } | ||
| func (r sortableRoutes) Less(i, j int) bool { | ||
| return r[i].Endpoint < r[j].Endpoint | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,86 @@ | ||
| /* | ||
| Package staticroute provides tools for building EC2 Instance Metadata static routes from | ||
| the set of data endpoints. A data endpoint is an one that serves instance specific data. | ||
| */ | ||
| package staticroute | ||
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| import ( | ||
| "sort" | ||
| "strings" | ||
| ) | ||
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| // Builder constructs a set of Route objects. Endpoints added via FromEndpoint will be result | ||
| // in a static route for each level of endpoint nesting. The root route is always an empty string. | ||
| // Endpoints that are descendable will be appended with a slash. For example, adding the endpoint | ||
| // "/foo/bar/baz" will result in the following routes: | ||
| // | ||
| // "/foo/bar" -> baz | ||
| // "/foo" -> bar/ | ||
| // "" -> foo/ | ||
| type Builder map[string]unorderedSet | ||
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| // NewBuilder returns a new Builder instance. | ||
| func NewBuilder() Builder { | ||
| return make(map[string]unorderedSet) | ||
| } | ||
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| // FromEndpoint adds endpoint to b. endpoint should be of URL path form such as "/foo/bar". | ||
| // FromEndpoint can be called multiple times. | ||
| func (b Builder) FromEndpoint(endpoint string) { | ||
| // Ensure our endpoint begins with a `/` so we can add to the root route for endpoint. | ||
| if !strings.HasPrefix(endpoint, "/") { | ||
| endpoint = "/" + endpoint | ||
| } | ||
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| // Split the endpoint into its components so we can build the pieces we need. | ||
| split := strings.Split(endpoint, "/") | ||
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| // Iterate over the components in reverse order so we can build parent paths for every | ||
| // level of path nesting and track the child part. | ||
| for i := len(split) - 1; i > 0; i-- { | ||
| concat := strings.Join(split[:i], "/") | ||
| if _, ok := b[concat]; !ok { | ||
| b[concat] = newUnorderedSet() | ||
| } | ||
| b[concat].Insert(split[i]) | ||
| } | ||
| } | ||
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| // Build returns a slice of Route objects containing an Endpoint and its associated child | ||
| // elements for the response body. The root route is identified by an empty string for the | ||
| // Endpoint field of Route. | ||
| func (b Builder) Build() []Route { | ||
| var routes sortableRoutes | ||
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| for parent, children := range b { | ||
| r := Route{Endpoint: parent} | ||
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| // Add children to the route prepending a slash for any child that is also a parent. | ||
| children.Range(func(child string) { | ||
| asParent := strings.Join([]string{parent, child}, "/") | ||
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| // If the child is also a parent, append a slash so the consumer knows it is a | ||
| // descendable directory. | ||
| if _, ok := b[asParent]; ok { | ||
| child += "/" | ||
| } | ||
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| r.Children = append(r.Children, child) | ||
| }) | ||
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| sort.Strings(r.Children) | ||
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| routes = append(routes, r) | ||
| } | ||
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| // Sort for determinism, no other reason. | ||
| sort.Sort(routes) | ||
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| return routes | ||
| } | ||
|
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| // Route is an endpoint and its associated child elements. | ||
| type Route struct { | ||
| Endpoint string | ||
| Children []string | ||
| } |
124 changes: 124 additions & 0 deletions
124
internal/frontend/ec2/internal/staticroute/staticroute_test.go
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,124 @@ | ||
| package staticroute_test | ||
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| import ( | ||
| "testing" | ||
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| "github.com/google/go-cmp/cmp" | ||
| . "github.com/tinkerbell/hegel/internal/frontend/ec2/internal/staticroute" | ||
| ) | ||
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| func TestBuilder(t *testing.T) { | ||
| cases := []struct { | ||
| Name string | ||
| Endpoints []string | ||
| Routes []Route | ||
| }{ | ||
| { | ||
| Name: "NoEndpoints", | ||
| Endpoints: []string{}, | ||
| Routes: nil, | ||
| }, | ||
| { | ||
| Name: "MissingLeadingSlash", | ||
| Endpoints: []string{"foo/bar"}, | ||
| Routes: []Route{ | ||
| { | ||
| Endpoint: "", | ||
| Children: []string{"foo/"}, | ||
| }, | ||
| { | ||
| Endpoint: "/foo", | ||
| Children: []string{"bar"}, | ||
| }, | ||
| }, | ||
| }, | ||
| { | ||
| Name: "SingleEndpoint", | ||
| Endpoints: []string{"/foo/bar"}, | ||
| Routes: []Route{ | ||
| { | ||
| Endpoint: "", | ||
| Children: []string{"foo/"}, | ||
| }, | ||
| { | ||
| Endpoint: "/foo", | ||
| Children: []string{"bar"}, | ||
| }, | ||
| }, | ||
| }, | ||
| { | ||
| Name: "NestedEndpoints", | ||
| Endpoints: []string{"/foo/bar", "/foo/bar/baz"}, | ||
| Routes: []Route{ | ||
| { | ||
| Endpoint: "", | ||
| Children: []string{"foo/"}, | ||
| }, | ||
| { | ||
| Endpoint: "/foo", | ||
| Children: []string{"bar/"}, | ||
| }, | ||
| { | ||
| Endpoint: "/foo/bar", | ||
| Children: []string{"baz"}, | ||
| }, | ||
| }, | ||
| }, | ||
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| { | ||
| Name: "DeepNestedEndpoints", | ||
| Endpoints: []string{"/foo/bar/baz/qux"}, | ||
| Routes: []Route{ | ||
| { | ||
| Endpoint: "", | ||
| Children: []string{"foo/"}, | ||
| }, | ||
| { | ||
| Endpoint: "/foo", | ||
| Children: []string{"bar/"}, | ||
| }, | ||
| { | ||
| Endpoint: "/foo/bar", | ||
| Children: []string{"baz/"}, | ||
| }, | ||
| { | ||
| Endpoint: "/foo/bar/baz", | ||
| Children: []string{"qux"}, | ||
| }, | ||
| }, | ||
| }, | ||
| { | ||
| Name: "MultipleDifferentiatedEndpoints", | ||
| Endpoints: []string{"/foo/bar", "/baz/qux"}, | ||
| Routes: []Route{ | ||
| { | ||
| Endpoint: "", | ||
| Children: []string{"baz/", "foo/"}, | ||
| }, | ||
| { | ||
| Endpoint: "/baz", | ||
| Children: []string{"qux"}, | ||
| }, | ||
| { | ||
| Endpoint: "/foo", | ||
| Children: []string{"bar"}, | ||
| }, | ||
| }, | ||
| }, | ||
| } | ||
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| for _, tc := range cases { | ||
| t.Run(tc.Name, func(t *testing.T) { | ||
| builder := NewBuilder() | ||
| for _, ep := range tc.Endpoints { | ||
| builder.FromEndpoint(ep) | ||
| } | ||
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| routes := builder.Build() | ||
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| if !cmp.Equal(tc.Routes, routes) { | ||
| t.Fatalf("Unexpected routes: %s", cmp.Diff(tc.Routes, routes)) | ||
| } | ||
| }) | ||
| } | ||
| } |
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