VSCode Golang dlv調試數據截斷問題及處理方法

使用VSCode對Golang程序進行調試時會遇到數據截斷問題，string只顯示前64個字符，array只顯示前64個數據。經查dlv是支持以參數方式來控制的。

發現VSCode的Golang插件裡面有個叫做go.delveConfig的配置，是可以設置dlv參數的。分享一下我的整個Golang配置：

  "go.buildOnSave": "off",    "go.formatTool": "goimports",    "go.lintTool": "golangci-lint", //go get -u github.com/golangci/golangci-lint/cmd/golangci-lint    "go.autocompleteUnimportedPackages": true,    "go.gotoSymbol.includeImports": true,    "go.useLanguageServer": true,    "go.delveConfig": {      "dlvLoadConfig": {        "followPointers": true,        "maxVariableRecurse": 3,        "maxStringLen": 1024,        "maxArrayValues": 1024,        "maxStructFields": -1      },    },    "[go]": {      "editor.formatOnSave": true,      "editor.codeActionsOnSave": {        "source.organizeImports": true      }    },

需要改的主要是maxStringLen、maxArrayValues、maxVariableRecurse這三個字段。

參考：https://stackoverflow.com/questions/52416263/how-do-i-print-the-full-value-of-a-string-variable-in-delve

ps：下面看下Golang dlv 工具debug 調試注意項

總結一下關於Go 的調試工具dlv：https://github.com/derekparker/delve 的使用注意項。

安裝：

go get -u github.com/go-delve/delve/cmd/dlv

配置：

以Centos為例

  export GOROOT=/usr/lib/golang  export GOPATH=$HOME/go  export PATH=$PATH:$GOPATH/bin

使用

以某go服務為例：

• dlv debug xxx.go 指定需要debug的文件

• 進入dlv交互式窗口後，b: 指定斷點

• r arg 指定運行參數

• n 執行一行

• c 運行至斷點或程序結束

  dlv debug /home/xxx/server.go  (dlv) b /home/xxx/server.go:258  (dlv) r 1  (dlv) n  (dlv) c

注意： b: 指定斷點時，若該行號對應的代碼內容為無具體語義的代碼（括號、註釋等），則會報錯：

Command failed: could not find /home/xxx/server.go:258

此時可用list 命令先查看上下文代碼，避免將無具體語義的代碼設為斷點。

命令集

The following commands are available:
     args ------------------------ Print function arguments.
     break (alias: b) ------------ Sets a breakpoint.
     breakpoints (alias: bp) ----- Print out info for active breakpoints.
     call ------------------------ Resumes process, injecting a function call (EXPERIMENTAL!!!)
     clear ----------------------- Deletes breakpoint.
     clearall -------------------- Deletes multiple breakpoints.
     condition (alias: cond) ----- Set breakpoint condition.
     config ---------------------- Changes configuration parameters.
     continue (alias: c) --------- Run until breakpoint or program termination.
     deferred -------------------- Executes command in the context of a deferred call.
     disassemble (alias: disass) - Disassembler.
     down ------------------------ Move the current frame down.
     edit (alias: ed) ------------ Open where you are in $DELVE_EDITOR or $EDITOR
     exit (alias: quit | q) ------ Exit the debugger.
     frame ----------------------- Set the current frame, or execute command on a different frame.
     funcs ----------------------- Print list of functions.
     goroutine ------------------- Shows or changes current goroutine
     goroutines ------------------ List program goroutines.
     help (alias: h) ------------- Prints the help message.
     list (alias: ls | l) -------- Show source code.
     locals ---------------------- Print local variables.
     next (alias: n) ------------- Step over to next source line.
     on -------------------------- Executes a command when a breakpoint is hit.
     print (alias: p) ------------ Evaluate an expression.
     regs ------------------------ Print contents of CPU registers.
     restart (alias: r) ---------- Restart process.
     set ------------------------- Changes the value of a variable.
     source ---------------------- Executes a file containing a list of delve commands
     sources --------------------- Print list of source files.
     stack (alias: bt) ----------- Print stack trace.
     step (alias: s) ------------- Single step through program.
     step-instruction (alias: si)  Single step a single cpu instruction.
     stepout --------------------- Step out of the current function.
     thread (alias: tr) ---------- Switch to the specified thread.
     threads --------------------- Print out info for every traced thread.
     trace (alias: t) ------------ Set tracepoint.
     types ----------------------- Print list of types
     up -------------------------- Move the current frame up.
     vars ------------------------ Print package variables.
     whatis ---------------------- Prints type of an expression.