diff options
Diffstat (limited to 'modules/caddyhttp/starlarkmw')
| -rw-r--r-- | modules/caddyhttp/starlarkmw/example/caddy.json | 19 | ||||
| -rw-r--r-- | modules/caddyhttp/starlarkmw/internal/lib/module.go | 165 | ||||
| -rw-r--r-- | modules/caddyhttp/starlarkmw/starlarkmw.go | 172 | ||||
| -rw-r--r-- | modules/caddyhttp/starlarkmw/tools/gen/example.star | 40 |
4 files changed, 396 insertions, 0 deletions
diff --git a/modules/caddyhttp/starlarkmw/example/caddy.json b/modules/caddyhttp/starlarkmw/example/caddy.json new file mode 100644 index 0000000..66f9f2c --- /dev/null +++ b/modules/caddyhttp/starlarkmw/example/caddy.json @@ -0,0 +1,19 @@ +{ + "apps": { + "http": { + "servers": { + "MY_SERVER": { + "listen": [":3001"], + "routes": [ + { + "handle": { + "handler": "starlark", + "script": "def setup(r):\n\t# create some middlewares specific to this request\n\ttemplates = loadModule('http.handlers.templates', {'include_root': './includes'})\n\tmidChain = execute([templates])\n\ndef serveHTTP (rw, r):\n\trw.Write('Hello world, from Starlark!')\n" + } + } + ] + } + } + } + } +}
\ No newline at end of file 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 +} diff --git a/modules/caddyhttp/starlarkmw/starlarkmw.go b/modules/caddyhttp/starlarkmw/starlarkmw.go new file mode 100644 index 0000000..007ddb4 --- /dev/null +++ b/modules/caddyhttp/starlarkmw/starlarkmw.go @@ -0,0 +1,172 @@ +package starlarkmw + +import ( + "context" + "fmt" + "net/http" + + "github.com/caddyserver/caddy/v2" + "github.com/caddyserver/caddy/v2/modules/caddyhttp" + caddyscript "github.com/caddyserver/caddy/v2/pkg/caddyscript/lib" + "github.com/caddyserver/caddy/v2/modules/caddyhttp/starlarkmw/internal/lib" + "github.com/starlight-go/starlight/convert" + "go.starlark.net/starlark" +) + +func init() { + caddy.RegisterModule(StarlarkMW{}) +} + +// StarlarkMW represents a middleware responder written in starlark +type StarlarkMW struct { + Script string `json:"script"` + serveHTTP *starlark.Function + setup *starlark.Function + thread *starlark.Thread + loadMiddleware *lib.LoadMiddleware + execute *lib.Execute + globals *starlark.StringDict + gctx caddy.Context + rctx caddy.Context + rcancel context.CancelFunc +} + +// CaddyModule returns the Caddy module information. +func (StarlarkMW) CaddyModule() caddy.ModuleInfo { + return caddy.ModuleInfo{ + Name: "http.handlers.starlark", + New: func() caddy.Module { return new(StarlarkMW) }, + } +} + +// ServeHTTP responds to an http request with starlark. +func (s *StarlarkMW) ServeHTTP(w http.ResponseWriter, r *http.Request) error { + var mwcancel context.CancelFunc + var mwctx caddy.Context + + // call setup() to prepare the middleware chain if it is defined + if s.setup != nil { + mwctx, mwcancel = caddy.NewContext(s.gctx) + defer mwcancel() + + s.loadMiddleware.Ctx = mwctx + args := starlark.Tuple{caddyscript.HTTPRequest{Req: r}} + + _, err := starlark.Call(new(starlark.Thread), s.setup, args, nil) + if err != nil { + return fmt.Errorf("starlark setup(), %v", err) + } + } + + // dynamically build middleware chain for each request + stack := caddyhttp.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error { + wr, err := convert.ToValue(w) + if err != nil { + return fmt.Errorf("cannot convert response writer to starlark value") + } + + args := starlark.Tuple{wr, caddyscript.HTTPRequest{Req: r}} + v, err := starlark.Call(new(starlark.Thread), s.serveHTTP, args, nil) + if err != nil { + return fmt.Errorf("starlark serveHTTP(), %v", err) + } + + // if a responder type was returned from starlark we should run it otherwise it + // is expected to handle the request + if resp, ok := v.(lib.ResponderModule); ok { + return resp.Instance.ServeHTTP(w, r) + } + + return nil + }) + + // TODO :- make middlewareResponseWriter exported and wrap w with that + var mid []caddyhttp.Middleware + for _, m := range s.execute.Modules { + mid = append(mid, func(next caddyhttp.HandlerFunc) caddyhttp.HandlerFunc { + return func(w http.ResponseWriter, r *http.Request) error { + return m.Instance.ServeHTTP(w, r, next) + } + }) + } + + for i := len(mid) - 1; i >= 0; i-- { + stack = mid[i](stack) + } + + s.execute.Modules = nil + + return stack(w, r) +} + +// Cleanup cleans up any modules loaded during the creation of a starlark route. +func (s *StarlarkMW) Cleanup() error { + s.rcancel() + return nil +} + +// Provision sets up the starlark env. +func (s *StarlarkMW) Provision(ctx caddy.Context) error { + // store global context + s.gctx = ctx + + // setup context for cleaning up any modules loaded during starlark script parsing phase + rctx, cancel := caddy.NewContext(ctx) + s.rcancel = cancel + + // setup starlark global env + env := make(starlark.StringDict) + loadMiddleware := lib.LoadMiddleware{} + loadResponder := lib.LoadResponder{ + Ctx: rctx, + } + execute := lib.Execute{} + + lr := starlark.NewBuiltin("loadResponder", loadResponder.Run) + lr = lr.BindReceiver(&loadResponder) + env["loadResponder"] = lr + + lm := starlark.NewBuiltin("loadMiddleware", loadMiddleware.Run) + lm = lm.BindReceiver(&loadMiddleware) + env["loadMiddleware"] = lm + + ex := starlark.NewBuiltin("execute", execute.Run) + ex = ex.BindReceiver(&execute) + env["execute"] = ex + + // import caddyscript lib + env["time"] = caddyscript.Time{} + env["regexp"] = caddyscript.Regexp{} + + // configure starlark + thread := new(starlark.Thread) + s.thread = thread + + // run starlark script + globals, err := starlark.ExecFile(thread, "", s.Script, env) + if err != nil { + return fmt.Errorf("starlark exec file: %v", err.Error()) + } + + // extract defined methods to setup middleware chain and responder, setup is not required + var setup *starlark.Function + if _, ok := globals["setup"]; ok { + setup, ok = globals["setup"].(*starlark.Function) + if !ok { + return fmt.Errorf("setup function not defined in starlark script") + } + } + + serveHTTP, ok := globals["serveHTTP"].(*starlark.Function) + if !ok { + return fmt.Errorf("serveHTTP function not defined in starlark script") + } + + s.setup = setup + s.serveHTTP = serveHTTP + s.loadMiddleware = &loadMiddleware + s.execute = &execute + s.globals = &globals + + return nil +} diff --git a/modules/caddyhttp/starlarkmw/tools/gen/example.star b/modules/caddyhttp/starlarkmw/tools/gen/example.star new file mode 100644 index 0000000..6ccab32 --- /dev/null +++ b/modules/caddyhttp/starlarkmw/tools/gen/example.star @@ -0,0 +1,40 @@ +# any module that provisions resources +proxyConfig = { + 'load_balance_type': 'round_robin', + 'upstreams': [ + { + 'host': 'http://localhost:8080', + 'circuit_breaker': { + 'type': 'status_ratio', + 'threshold': 0.5 + } + }, + { + 'host': 'http://localhost:8081' + } + ] +} + +sfConfig = { + 'root': '/Users/dev/Desktop', + 'browse': {}, +} + +proxy = loadResponder('reverse_proxy', proxyConfig) +static_files = loadResponder('file_server', sfConfig) + +def setup(r): + # create some middlewares specific to this request + mid = [] + + if r.query.get('log') == 'true': + logMid = loadMiddleware('log', {'file': 'access.log'}) + mid.append(logMid) + + execute(mid) + +def serveHTTP(w, r): + if r.url.find('static') > 0: + return static_files + + return proxy |