From 26cc8837084f9cea6057e9908f0b5bde0eb15d3e Mon Sep 17 00:00:00 2001 From: Matthew Holt Date: Thu, 10 Oct 2019 11:02:16 -0600 Subject: http: Add Starlark handler This migrates a feature that was previously reserved for enterprise users, according to #2786. The Starlark integration needs to be updated since this was made before some significant changes in the v2 code base. When functional, it makes it possible to have very dynamic HTTP handlers. This will be a long-term ongoing project. Credit to Danny Navarro --- .../caddyhttp/starlarkmw/internal/lib/module.go | 165 +++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 modules/caddyhttp/starlarkmw/internal/lib/module.go (limited to 'modules/caddyhttp/starlarkmw/internal/lib/module.go') diff --git a/modules/caddyhttp/starlarkmw/internal/lib/module.go b/modules/caddyhttp/starlarkmw/internal/lib/module.go new file mode 100644 index 0000000..a7164cd --- /dev/null +++ b/modules/caddyhttp/starlarkmw/internal/lib/module.go @@ -0,0 +1,165 @@ +package lib + +import ( + "encoding/json" + "fmt" + "strings" + + "github.com/caddyserver/caddy/v2/modules/caddyhttp" + + "github.com/caddyserver/caddy/v2" + "go.starlark.net/starlark" +) + +// ResponderModule represents a module that satisfies the caddyhttp handler. +type ResponderModule struct { + Name string + Cfg json.RawMessage + Instance caddyhttp.Handler +} + +func (r ResponderModule) Freeze() {} +func (r ResponderModule) Hash() (uint32, error) { return 0, fmt.Errorf("unhashable: responder module") } +func (r ResponderModule) String() string { return "responder module" } +func (r ResponderModule) Type() string { return "responder module" } +func (r ResponderModule) Truth() starlark.Bool { return true } + +// Middleware represents a module that satisfies the starlark Value interface. +type Middleware struct { + Name string + Cfg json.RawMessage + Instance caddyhttp.MiddlewareHandler +} + +func (r Middleware) Freeze() {} +func (r Middleware) Hash() (uint32, error) { return 0, fmt.Errorf("unhashable: middleware") } +func (r Middleware) String() string { return "middleware" } +func (r Middleware) Type() string { return "middleware" } +func (r Middleware) Truth() starlark.Bool { return true } + +// LoadMiddleware represents the method exposed to starlark to load a Caddy module. +type LoadMiddleware struct { + Middleware Middleware + Ctx caddy.Context +} + +func (r LoadMiddleware) Freeze() {} +func (r LoadMiddleware) Hash() (uint32, error) { return 0, fmt.Errorf("unhashable: loadMiddleware") } +func (r LoadMiddleware) String() string { return "loadMiddleware" } +func (r LoadMiddleware) Type() string { return "function: loadMiddleware" } +func (r LoadMiddleware) Truth() starlark.Bool { return true } + +// Run is the method bound to the starlark loadMiddleware function. +func (r *LoadMiddleware) Run(thread *starlark.Thread, fn *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) { + var name string + var cfg *starlark.Dict + err := starlark.UnpackPositionalArgs(fn.Name(), args, kwargs, 2, &name, &cfg) + if err != nil { + return starlark.None, fmt.Errorf("unpacking arguments: %v", err.Error()) + } + + js := json.RawMessage(cfg.String()) + + if strings.Index(name, "http.handlers.") == -1 { + name = fmt.Sprintf("http.handlers.%s", name) + } + + inst, err := r.Ctx.LoadModule(name, js) + if err != nil { + return starlark.None, err + } + + mid, ok := inst.(caddyhttp.MiddlewareHandler) + if !ok { + return starlark.None, fmt.Errorf("could not assert as middleware handler") + } + + m := Middleware{ + Name: name, + Cfg: js, + Instance: mid, + } + + r.Middleware = m + + return m, nil +} + +// LoadResponder represents the method exposed to starlark to load a Caddy middleware responder. +type LoadResponder struct { + Module ResponderModule + Ctx caddy.Context +} + +func (r LoadResponder) Freeze() {} +func (r LoadResponder) Hash() (uint32, error) { return 0, fmt.Errorf("unhashable: loadModule") } +func (r LoadResponder) String() string { return "loadModule" } +func (r LoadResponder) Type() string { return "function: loadModule" } +func (r LoadResponder) Truth() starlark.Bool { return true } + +// Run is the method bound to the starlark loadResponder function. +func (r *LoadResponder) Run(thread *starlark.Thread, fn *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) { + var name string + var cfg *starlark.Dict + err := starlark.UnpackPositionalArgs(fn.Name(), args, kwargs, 2, &name, &cfg) + if err != nil { + return starlark.None, fmt.Errorf("unpacking arguments: %v", err.Error()) + } + + js := json.RawMessage(cfg.String()) + + if strings.Index(name, "http.handlers.") == -1 { + name = fmt.Sprintf("http.handlers.%s", name) + } + + inst, err := r.Ctx.LoadModule(name, js) + if err != nil { + return starlark.None, err + } + + res, ok := inst.(caddyhttp.Handler) + if !ok { + return starlark.None, fmt.Errorf("could not assert as responder") + } + + m := ResponderModule{ + Name: name, + Cfg: js, + Instance: res, + } + + r.Module = m + + return m, nil +} + +// Execute represents the method exposed to starlark to build a middleware chain. +type Execute struct { + Modules []Middleware +} + +func (r Execute) Freeze() {} +func (r Execute) Hash() (uint32, error) { return 0, fmt.Errorf("unhashable: execute") } +func (r Execute) String() string { return "execute" } +func (r Execute) Type() string { return "function: execute" } +func (r Execute) Truth() starlark.Bool { return true } + +// Run is the method bound to the starlark execute function. +func (r *Execute) Run(thread *starlark.Thread, fn *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) { + var mids *starlark.List + err := starlark.UnpackPositionalArgs(fn.Name(), args, kwargs, 1, &mids) + if err != nil { + return starlark.None, fmt.Errorf("unpacking arguments: %v", err.Error()) + } + + for i := 0; i < mids.Len(); i++ { + val, ok := mids.Index(i).(Middleware) + if !ok { + return starlark.None, fmt.Errorf("cannot get module from execute") + } + + r.Modules = append(r.Modules, val) + } + + return starlark.None, nil +} -- cgit v1.2.3