MainframeMaster

COBOL Configuration Management

Configuration management controls program behavior through environment settings, runtime parameters, and configuration data. Learn to make programs flexible and maintainable through proper configuration.

Runtime Parameters

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       *> JCL parameter passing
       //STEP1 EXEC PGM=CUSTPROC,PARM='ENV=PROD,DEBUG=N'
       
       *> Program parameter handling
       LINKAGE SECTION.
       01 PARM-LENGTH PIC S9(4) COMP.
       01 PARM-DATA PIC X(100).
       
       PROCEDURE DIVISION USING PARM-LENGTH PARM-DATA.
       IF PARM-LENGTH > 0
           UNSTRING PARM-DATA DELIMITED BY ','
               INTO ENV-VALUE FILLER DEBUG-VALUE
           END-UNSTRING
       ELSE
           MOVE 'DEV' TO ENV-VALUE
           MOVE 'Y' TO DEBUG-VALUE
       END-IF.

Pass runtime parameters through JCL PARM parameter. The program receives parameter length and data in the LINKAGE SECTION. Parse parameters to set program behavior without code changes.

Environment Variables

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       *> Read environment variables
       CALL 'CEE3INF' USING ENV-VAR-NAME
                            ENV-VAR-VALUE
                            ENV-VAR-LENGTH
                            RETURN-CODE.
       
       *> Set program behavior based on environment
       IF ENV-VAR-VALUE = 'PRODUCTION'
           MOVE 'N' TO DEBUG-FLAG
           MOVE 'PROD-DB' TO DATABASE-NAME
       ELSE IF ENV-VAR-VALUE = 'DEVELOPMENT'
           MOVE 'Y' TO DEBUG-FLAG
           MOVE 'DEV-DB' TO DATABASE-NAME
       ELSE
           MOVE 'Y' TO DEBUG-FLAG
           MOVE 'TEST-DB' TO DATABASE-NAME
       END-IF.

Use environment variables to control program behavior across different environments. Read environment variables using system calls and adjust program settings accordingly.

Configuration Files

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       *> Configuration file structure
       FD CONFIG-FILE.
       01 CONFIG-RECORD.
           05 CONFIG-KEY PIC X(20).
           05 CONFIG-VALUE PIC X(50).
       
       *> Read configuration at startup
       OPEN INPUT CONFIG-FILE
       PERFORM UNTIL EOF
           READ CONFIG-FILE AT END SET EOF TO TRUE
           NOT AT END
               EVALUATE CONFIG-KEY
                   WHEN 'MAX-RECORDS'
                       MOVE CONFIG-VALUE TO MAX-RECORD-COUNT
                   WHEN 'DEBUG-LEVEL'
                       MOVE CONFIG-VALUE TO DEBUG-LEVEL
                   WHEN 'LOG-FILE'
                       MOVE CONFIG-VALUE TO LOG-FILE-NAME
               END-EVALUATE
           END-READ
       END-PERFORM
       CLOSE CONFIG-FILE.

Use configuration files to store program settings externally. Read configuration at program startup and set internal variables accordingly. This allows changes without recompiling.

System Configuration

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       *> System-level configuration
       WORKING-STORAGE SECTION.
       01 SYSTEM-CONFIG.
           05 MAX-MEMORY PIC 9(9) VALUE 1000000.
           05 TIMEOUT-VALUE PIC 9(4) VALUE 300.
           05 RETRY-COUNT PIC 9 VALUE 3.
           05 LOG-LEVEL PIC X VALUE 'I'.  *> I=Info, W=Warning, E=Error
       
       *> Adjust behavior based on system resources
       IF SYSTEM-MEMORY < MAX-MEMORY
           MOVE 'SMALL-BATCH' TO PROCESSING-MODE
       ELSE
           MOVE 'LARGE-BATCH' TO PROCESSING-MODE
       END-IF.

Define system-level configuration parameters that control resource usage and program behavior. Adjust processing modes based on available system resources and requirements.

Dynamic Configuration

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       *> Runtime configuration changes
       PERFORM CHECK-CONFIG-UPDATE
       IF CONFIG-CHANGED = 'Y'
           PERFORM RELOAD-CONFIGURATION
           DISPLAY 'Configuration reloaded at ' CURRENT-TIME
       END-IF.
       
       *> Configuration validation
       PERFORM VALIDATE-CONFIGURATION
       IF CONFIG-VALID = 'N'
           DISPLAY 'Error: Invalid configuration'
           PERFORM ERROR-HANDLING
           STOP RUN
       END-IF.

Implement dynamic configuration that can be updated at runtime. Check for configuration changes and reload settings as needed. Always validate configuration before using it.

Configuration Validation

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       *> Validate configuration values
       IF MAX-RECORD-COUNT < 1 OR MAX-RECORD-COUNT > 1000000
           DISPLAY 'Error: Invalid MAX-RECORD-COUNT: ' MAX-RECORD-COUNT
           MOVE 10000 TO MAX-RECORD-COUNT
       END-IF.
       
       IF DEBUG-LEVEL NOT = 'I' AND DEBUG-LEVEL NOT = 'W' 
           AND DEBUG-LEVEL NOT = 'E'
           DISPLAY 'Error: Invalid DEBUG-LEVEL: ' DEBUG-LEVEL
           MOVE 'I' TO DEBUG-LEVEL
       END-IF.
       
       IF TIMEOUT-VALUE < 10 OR TIMEOUT-VALUE > 3600
           DISPLAY 'Error: Invalid TIMEOUT-VALUE: ' TIMEOUT-VALUE
           MOVE 300 TO TIMEOUT-VALUE
       END-IF.

Always validate configuration values to ensure they are within acceptable ranges. Provide default values for invalid configurations and log validation errors for troubleshooting.

Configuration Logging

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       *> Log configuration at startup
       DISPLAY 'Program Configuration:'
       DISPLAY 'Environment: ' ENV-VALUE
       DISPLAY 'Debug Level: ' DEBUG-LEVEL
       DISPLAY 'Max Records: ' MAX-RECORD-COUNT
       DISPLAY 'Timeout: ' TIMEOUT-VALUE ' seconds'
       DISPLAY 'Log File: ' LOG-FILE-NAME.

Log configuration settings at program startup for troubleshooting and audit purposes. This helps identify configuration-related issues and ensures proper program initialization.

Configuration Section

COBOL configuration section

Environment Setup

Development environment configuration