refactor(selector) replace pre and postrun with middleware pattern (#34)

* refactor(selector) replace pre and postrun with middleware pattern

* update docs

* update deps

Author: njayp

README.md

@@ -91,10 +91,11 @@ config := &ophis.Config{
             LocalFlagSelector: ophis.ExcludeFlags("token", "secret"),
             InheritedFlagSelector: ophis.NoFlags,  // Exclude persistent flags
 
-            // Add timeout for these commands
-            PreRun: func(ctx context.Context, ctr *mcp.CallToolRequest, ti ophis.ToolInput) (context.Context, *mcp.CallToolRequest, ophis.ToolInput) {
-                ctx, _ = context.WithTimeout(ctx, time.Minute)
-                return ctx, ctr, ti
+            // Middleware wraps command execution
+            Middleware: func(ctx context.Context, req *mcp.CallToolRequest, in ophis.ToolInput, next func(context.Context, *mcp.CallToolRequest, ophis.ToolInput) (*mcp.CallToolResult, ophis.ToolOutput, error)) (*mcp.CallToolResult, ophis.ToolOutput, error) {
+                ctx, cancel := context.WithTimeout(ctx, time.Minute)
+                defer cancel()
+                return next(ctx, req, in)
             },
         },
     },

doc.go

@@ -62,13 +62,14 @@
 //	            // Control which flags are included for matched commands
 //	            LocalFlagSelector: ophis.AllowFlags("namespace", "output"),
 //	            InheritedFlagSelector: ophis.NoFlags,  // Exclude persistent flags
-//	            // Optional: Add middleware hooks
-//	            PreRun: func(ctx context.Context, req *mcp.CallToolRequest, in ophis.ToolInput) (context.Context, *mcp.CallToolRequest, ophis.ToolInput) {
-//	                // Add timeout, logging, auth checks, etc.
-//	                return ctx, req, in
-//	            },
-//	            PostRun: func(ctx context.Context, req *mcp.CallToolRequest, in ophis.ToolInput, res *mcp.CallToolResult, out ophis.ToolOutput, err error) (*mcp.CallToolResult, ophis.ToolOutput, error) {
-//	                // Error handling, response filtering, metrics
+//	            // Optional: Add middleware to wrap execution
+//	            Middleware: func(ctx context.Context, req *mcp.CallToolRequest, in ophis.ToolInput, next func(context.Context, *mcp.CallToolRequest, ophis.ToolInput) (*mcp.CallToolResult, ophis.ToolOutput, error)) (*mcp.CallToolResult, ophis.ToolOutput, error) {
+//	                // Pre-execution: timeout, logging, auth checks, etc.
+//	                ctx, cancel := context.WithTimeout(ctx, time.Minute)
+//	                defer cancel()
+//	                // Execute the command
+//	                res, out, err := next(ctx, req, in)
+//	                // Post-execution: error handling, response filtering, metrics
 //	                return res, out, err
 //	            },
 //	        },
@@ -86,7 +87,7 @@
 //	}
 //
 // The selector system allows different commands to have different flag filtering
-// rules and middleware hooks, enabling precise control over the exposed tool surface.
+// rules and middleware, enabling precise control over the exposed tool surface.
 // Each selector defines which commands to match, which flags to include, and optional
-// PreRun/PostRun hooks for middleware functionality like timeouts, logging, and filtering.
+// middleware for wrapping execution with timeouts, logging, and response filtering.
 package ophis

docs/config.md

@@ -53,9 +53,10 @@ config := &ophis.Config{
         {
             // Read ops: timeout
             CmdSelector: ophis.AllowCmdsContaining("get", "list"),
-            PreRun: func(ctx context.Context, req *mcp.CallToolRequest, in ophis.ToolInput) (context.Context, *mcp.CallToolRequest, ophis.ToolInput) {
-                ctx, _ = context.WithTimeout(ctx, time.Minute)
-                return ctx, req, in
+            Middleware: func(ctx context.Context, req *mcp.CallToolRequest, in ophis.ToolInput, next func(context.Context, *mcp.CallToolRequest, ophis.ToolInput) (*mcp.CallToolResult, ophis.ToolOutput, error)) (*mcp.CallToolResult, ophis.ToolOutput, error) {
+                ctx, cancel := context.WithTimeout(ctx, time.Minute)
+                defer cancel()
+                return next(ctx, req, in)
             },
         },
         {
@@ -107,23 +108,23 @@ config := &ophis.Config{
 
 ## Middleware
 
-Add behavior before/after execution:
+Wrap execution with custom logic:
 
 ```go
-PreRun: func(ctx context.Context, req *mcp.CallToolRequest, in ophis.ToolInput) (context.Context, *mcp.CallToolRequest, ophis.ToolInput) {
-    // Add timeout
-    ctx, _ = context.WithTimeout(ctx, 30*time.Second)
+Middleware: func(ctx context.Context, req *mcp.CallToolRequest, in ophis.ToolInput, next func(context.Context, *mcp.CallToolRequest, ophis.ToolInput) (*mcp.CallToolResult, ophis.ToolOutput, error)) (*mcp.CallToolResult, ophis.ToolOutput, error) {
+    // Pre-execution: Add timeout
+    ctx, cancel := context.WithTimeout(ctx, 30*time.Second)
+    defer cancel()
 
-    // Validate input
+    // Pre-execution: Validate input
     if len(in.Args) > 10 {
         in.Args = in.Args[:10]
     }
 
-    return ctx, req, in
-}
+    // Execute the command
+    res, out, err := next(ctx, req, in)
 
-PostRun: func(ctx context.Context, req *mcp.CallToolRequest, in ophis.ToolInput, res *mcp.CallToolResult, out ophis.ToolOutput, err error) (*mcp.CallToolResult, ophis.ToolOutput, error) {
-    // Filter output
+    // Post-execution: Filter output
     if strings.Contains(out.StdOut, "SECRET") {
         out.StdOut = "[REDACTED]"
     }

docs/execution.md

@@ -4,9 +4,8 @@ When an AI assistant calls an MCP tool, Ophis executes your CLI as a subprocess.
 
 ## Execution Flow
 
-1. **PreRun Middleware** (optional) - Runs before execution
+1. **Middleware** (optional) - Wraps execution with custom logic
 2. **Command Execution** - Spawns CLI subprocess, captures output
-3. **PostRun Middleware** (optional) - Runs after execution
 
 ## Command Construction
 
@@ -54,7 +53,7 @@ Non-zero exit codes indicate command errors (not execution failures).
 ## Cancellation
 
 Execution can be cancelled by:
-- PreRun returning cancelled context
+- Middleware returning early without calling next
 - MCP client cancelling request
 - Parent context timeout
 

examples/argocd/go.mod

@@ -5,9 +5,9 @@ go 1.25.0
 replace github.com/njayp/ophis => ../../
 
 require (
-	github.com/argoproj/argo-cd/v3 v3.2.0
+	github.com/argoproj/argo-cd/v3 v3.2.1
 	github.com/njayp/ophis v0.0.0-00010101000000-000000000000
-	github.com/spf13/cobra v1.10.1
+	github.com/spf13/cobra v1.10.2
 	k8s.io/klog/v2 v2.130.1
 )
 
@@ -34,7 +34,7 @@ require (
 	github.com/RocketChat/Rocket.Chat.Go.SDK v0.0.0-20240116134246-a8cbe886bab0 // indirect
 	github.com/TomOnTime/utfutil v1.0.0 // indirect
 	github.com/alicebob/miniredis/v2 v2.35.0 // indirect
-	github.com/argoproj/gitops-engine v0.7.1-0.20251006172252-b89b0871b414 // indirect
+	github.com/argoproj/gitops-engine v0.7.1-0.20251108235403-13d5172d3ee2 // indirect
 	github.com/argoproj/notifications-engine v0.4.1-0.20250908182349-da04400446ff // indirect
 	github.com/argoproj/pkg v0.13.6 // indirect
 	github.com/argoproj/pkg/v2 v2.0.1 // indirect
@@ -221,7 +221,7 @@ require (
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/crypto v0.42.0 // indirect
 	golang.org/x/net v0.44.0 // indirect
-	golang.org/x/oauth2 v0.32.0 // indirect
+	golang.org/x/oauth2 v0.33.0 // indirect
 	golang.org/x/sync v0.17.0 // indirect
 	golang.org/x/sys v0.36.0 // indirect
 	golang.org/x/term v0.35.0 // indirect

examples/argocd/go.sum

@@ -103,10 +103,10 @@ github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be h1:9AeTilPcZAjCFI
 github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be/go.mod h1:ySMOLuWl6zY27l47sB3qLNK6tF2fkHG55UZxx8oIVo4=
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/appscode/go v0.0.0-20191119085241-0887d8ec2ecc/go.mod h1:OawnOmAL4ZX3YaPdN+8HTNwBveT1jMsqP74moa9XUbE=
-github.com/argoproj/argo-cd/v3 v3.2.0 h1:m2eGAV+nXQGgzZbH5SyJD5laaPW27mzWXBrgisUHY/0=
-github.com/argoproj/argo-cd/v3 v3.2.0/go.mod h1:l68oMtd8AljakHA+bKwev0WxfDu+GdnuwSrSAJHD1/4=
-github.com/argoproj/gitops-engine v0.7.1-0.20251006172252-b89b0871b414 h1:2w1vd2VZja7Mlf/rblJkp6/Eq8fNDuM7p6pI4PTAJhg=
-github.com/argoproj/gitops-engine v0.7.1-0.20251006172252-b89b0871b414/go.mod h1:2nqYZBhj8CfVZb3ATakZpi1KNb/yc7mpadIHslicTFI=
+github.com/argoproj/argo-cd/v3 v3.2.1 h1:rvrkW/JdH4V+xJgNDZI9wa/Ygd+fWoGbd1rAhvno22c=
+github.com/argoproj/argo-cd/v3 v3.2.1/go.mod h1:xDj7UVJxzRjiECiZ1qRGdIrDpqwWXZE+C12Xjbq7RQ8=
+github.com/argoproj/gitops-engine v0.7.1-0.20251108235403-13d5172d3ee2 h1:g9XclEd+1mYQtpLL3rMgYbMUdB3kEppw3+Jd1/H54VM=
+github.com/argoproj/gitops-engine v0.7.1-0.20251108235403-13d5172d3ee2/go.mod h1:2nqYZBhj8CfVZb3ATakZpi1KNb/yc7mpadIHslicTFI=
 github.com/argoproj/notifications-engine v0.4.1-0.20250908182349-da04400446ff h1:pGGAeHIktPuYCRl1Z540XdxPFnedqyUhJK4VgpyJZfY=
 github.com/argoproj/notifications-engine v0.4.1-0.20250908182349-da04400446ff/go.mod h1:d1RazGXWvKRFv9//rg4MRRR7rbvbE7XLgTSMT5fITTE=
 github.com/argoproj/pkg v0.13.6 h1:36WPD9MNYECHcO1/R1pj6teYspiK7uMQLCgLGft2abM=
@@ -791,8 +791,8 @@ github.com/spf13/cast v1.7.1 h1:cuNEagBQEHWN1FnbGEjCXL2szYEXqfJPbP2HNUaca9Y=
 github.com/spf13/cast v1.7.1/go.mod h1:ancEpBxwJDODSW/UG4rDrAqiKolqNNh2DX3mk86cAdo=
 github.com/spf13/cobra v0.0.3/go.mod h1:1l0Ry5zgKvJasoi3XT1TypsSe7PqH0Sj9dhYf7v3XqQ=
 github.com/spf13/cobra v1.5.0/go.mod h1:dWXEIy2H428czQCjInthrTRUg7yKbok+2Qi/yBIJoUM=
-github.com/spf13/cobra v1.10.1 h1:lJeBwCfmrnXthfAupyUTzJ/J4Nc1RsHC/mSRU2dll/s=
-github.com/spf13/cobra v1.10.1/go.mod h1:7SmJGaTHFVBY0jW4NXGluQoLvhqFQM+6XSKD+P4XaB0=
+github.com/spf13/cobra v1.10.2 h1:DMTTonx5m65Ic0GOoRY2c16WCbHxOOw6xxezuLaBpcU=
+github.com/spf13/cobra v1.10.2/go.mod h1:7C1pvHqHw5A4vrJfjNwvOdzYu0Gml16OCs2GRiTUUS4=
 github.com/spf13/pflag v0.0.0-20170130214245-9ff6c6923cff/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
@@ -1006,8 +1006,8 @@ golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4Iltr
 golang.org/x/oauth2 v0.0.0-20191202225959-858c2ad4c8b6/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20210514164344-f6687ab2804c/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
-golang.org/x/oauth2 v0.32.0 h1:jsCblLleRMDrxMN29H3z/k1KliIvpLgCkE6R8FXXNgY=
-golang.org/x/oauth2 v0.32.0/go.mod h1:lzm5WQJQwKZ3nwavOZ3IS5Aulzxi68dUSgRHujetwEA=
+golang.org/x/oauth2 v0.33.0 h1:4Q+qn+E5z8gPRJfmRy7C2gGG3T4jIprK6aSYgTXGRpo=
+golang.org/x/oauth2 v0.33.0/go.mod h1:lzm5WQJQwKZ3nwavOZ3IS5Aulzxi68dUSgRHujetwEA=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

examples/helm/go.mod

@@ -5,10 +5,10 @@ go 1.25.0
 replace github.com/njayp/ophis => ../../
 
 require (
-	github.com/njayp/ophis v1.0.8
-	github.com/spf13/cobra v1.10.1
-	helm.sh/helm/v4 v4.0.0-rc.1
-	k8s.io/client-go v0.34.1
+	github.com/njayp/ophis v1.0.9
+	github.com/spf13/cobra v1.10.2
+	helm.sh/helm/v4 v4.0.1
+	k8s.io/client-go v0.34.2
 )
 
 require (
@@ -29,7 +29,7 @@ require (
 	github.com/clipperhouse/uax29/v2 v2.3.0 // indirect
 	github.com/cloudflare/circl v1.6.1 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.7 // indirect
-	github.com/cyphar/filepath-securejoin v0.6.0 // indirect
+	github.com/cyphar/filepath-securejoin v0.6.1 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/dylibso/observe-sdk/go v0.0.0-20240828172851-9145d8ad07e1 // indirect
 	github.com/emicklei/go-restful/v3 v3.13.0 // indirect
@@ -42,33 +42,33 @@ require (
 	github.com/go-errors/errors v1.5.1 // indirect
 	github.com/go-gorp/gorp/v3 v3.1.0 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
-	github.com/go-openapi/jsonpointer v0.22.1 // indirect
-	github.com/go-openapi/jsonreference v0.21.2 // indirect
-	github.com/go-openapi/swag v0.25.1 // indirect
-	github.com/go-openapi/swag/cmdutils v0.25.1 // indirect
-	github.com/go-openapi/swag/conv v0.25.1 // indirect
-	github.com/go-openapi/swag/fileutils v0.25.1 // indirect
-	github.com/go-openapi/swag/jsonname v0.25.1 // indirect
-	github.com/go-openapi/swag/jsonutils v0.25.1 // indirect
-	github.com/go-openapi/swag/loading v0.25.1 // indirect
-	github.com/go-openapi/swag/mangling v0.25.1 // indirect
-	github.com/go-openapi/swag/netutils v0.25.1 // indirect
-	github.com/go-openapi/swag/stringutils v0.25.1 // indirect
-	github.com/go-openapi/swag/typeutils v0.25.1 // indirect
-	github.com/go-openapi/swag/yamlutils v0.25.1 // indirect
+	github.com/go-openapi/jsonpointer v0.22.3 // indirect
+	github.com/go-openapi/jsonreference v0.21.3 // indirect
+	github.com/go-openapi/swag v0.25.4 // indirect
+	github.com/go-openapi/swag/cmdutils v0.25.4 // indirect
+	github.com/go-openapi/swag/conv v0.25.4 // indirect
+	github.com/go-openapi/swag/fileutils v0.25.4 // indirect
+	github.com/go-openapi/swag/jsonname v0.25.4 // indirect
+	github.com/go-openapi/swag/jsonutils v0.25.4 // indirect
+	github.com/go-openapi/swag/loading v0.25.4 // indirect
+	github.com/go-openapi/swag/mangling v0.25.4 // indirect
+	github.com/go-openapi/swag/netutils v0.25.4 // indirect
+	github.com/go-openapi/swag/stringutils v0.25.4 // indirect
+	github.com/go-openapi/swag/typeutils v0.25.4 // indirect
+	github.com/go-openapi/swag/yamlutils v0.25.4 // indirect
 	github.com/gobwas/glob v0.2.3 // indirect
 	github.com/gofrs/flock v0.13.0 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/google/btree v1.1.3 // indirect
-	github.com/google/gnostic-models v0.7.0 // indirect
+	github.com/google/gnostic-models v0.7.1 // indirect
 	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/google/jsonschema-go v0.3.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/gorilla/websocket v1.5.4-0.20250319132907-e064f32e3674 // indirect
 	github.com/gosuri/uitable v0.0.4 // indirect
 	github.com/gregjones/httpcache v0.0.0-20190611155906-901d90724c79 // indirect
 	github.com/huandu/xstrings v1.5.0 // indirect
-	github.com/ianlancetaylor/demangle v0.0.0-20250628045327-2d64ad6b7ec5 // indirect
+	github.com/ianlancetaylor/demangle v0.0.0-20251118225945-96ee0021ea0f // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/jmoiron/sqlx v1.4.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
@@ -94,48 +94,47 @@ require (
 	github.com/opencontainers/image-spec v1.1.1 // indirect
 	github.com/peterbourgon/diskv v2.0.1+incompatible // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
-	github.com/rubenv/sql-migrate v1.8.0 // indirect
+	github.com/rubenv/sql-migrate v1.8.1 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	github.com/santhosh-tekuri/jsonschema/v6 v6.0.2 // indirect
 	github.com/shopspring/decimal v1.4.0 // indirect
 	github.com/spf13/cast v1.10.0 // indirect
 	github.com/spf13/pflag v1.0.10 // indirect
 	github.com/tetratelabs/wabin v0.0.0-20230304001439-f6f874872834 // indirect
-	github.com/tetratelabs/wazero v1.9.0 // indirect
+	github.com/tetratelabs/wazero v1.10.1 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	github.com/xlab/treeprint v1.2.0 // indirect
 	github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
 	go.opentelemetry.io/proto/otlp v1.9.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
-	golang.org/x/crypto v0.43.0 // indirect
-	golang.org/x/net v0.46.0 // indirect
-	golang.org/x/oauth2 v0.32.0 // indirect
-	golang.org/x/sync v0.17.0 // indirect
-	golang.org/x/sys v0.37.0 // indirect
-	golang.org/x/term v0.36.0 // indirect
-	golang.org/x/text v0.30.0 // indirect
+	golang.org/x/crypto v0.45.0 // indirect
+	golang.org/x/net v0.47.0 // indirect
+	golang.org/x/oauth2 v0.33.0 // indirect
+	golang.org/x/sync v0.18.0 // indirect
+	golang.org/x/sys v0.38.0 // indirect
+	golang.org/x/term v0.37.0 // indirect
+	golang.org/x/text v0.31.0 // indirect
 	golang.org/x/time v0.14.0 // indirect
 	google.golang.org/protobuf v1.36.10 // indirect
 	gopkg.in/evanphx/json-patch.v4 v4.13.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
-	k8s.io/api v0.34.1 // indirect
-	k8s.io/apiextensions-apiserver v0.34.1 // indirect
-	k8s.io/apimachinery v0.34.1 // indirect
-	k8s.io/apiserver v0.34.1 // indirect
-	k8s.io/cli-runtime v0.34.1 // indirect
-	k8s.io/component-base v0.34.1 // indirect
+	k8s.io/api v0.34.2 // indirect
+	k8s.io/apiextensions-apiserver v0.34.2 // indirect
+	k8s.io/apimachinery v0.34.2 // indirect
+	k8s.io/apiserver v0.34.2 // indirect
+	k8s.io/cli-runtime v0.34.2 // indirect
+	k8s.io/component-base v0.34.2 // indirect
 	k8s.io/klog/v2 v2.130.1 // indirect
-	k8s.io/kube-openapi v0.0.0-20250910181357-589584f1c912 // indirect
-	k8s.io/kubectl v0.34.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20251125145642-4e65d59e963e // indirect
+	k8s.io/kubectl v0.34.2 // indirect
 	k8s.io/utils v0.0.0-20251002143259-bc988d571ff4 // indirect
 	oras.land/oras-go/v2 v2.6.0 // indirect
 	sigs.k8s.io/controller-runtime v0.22.4 // indirect
 	sigs.k8s.io/json v0.0.0-20250730193827-2d320260d730 // indirect
-	sigs.k8s.io/kustomize/api v0.20.1 // indirect
-	sigs.k8s.io/kustomize/kyaml v0.20.1 // indirect
+	sigs.k8s.io/kustomize/api v0.21.0 // indirect
+	sigs.k8s.io/kustomize/kyaml v0.21.0 // indirect
 	sigs.k8s.io/randfill v1.0.0 // indirect
-	sigs.k8s.io/structured-merge-diff/v6 v6.3.0 // indirect
+	sigs.k8s.io/structured-merge-diff/v6 v6.3.1 // indirect
 	sigs.k8s.io/yaml v1.6.0 // indirect
 )