k8s.io/registry.k8s.io@v0.3.1/pkg/net/cloudcidrs/internal/ranges2go/gen.go (about)

     1  /*
     2  Copyright 2022 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package main
    18  
    19  import (
    20  	"fmt"
    21  	"io"
    22  	"sort"
    23  )
    24  
    25  const fileHeader = `/*
    26  Copyright The Kubernetes Authors.
    27  
    28  Licensed under the Apache License, Version 2.0 (the "License");
    29  you may not use this file except in compliance with the License.
    30  You may obtain a copy of the License at
    31  
    32      http://www.apache.org/licenses/LICENSE-2.0
    33  
    34  Unless required by applicable law or agreed to in writing, software
    35  distributed under the License is distributed on an "AS IS" BASIS,
    36  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    37  See the License for the specific language governing permissions and
    38  limitations under the License.
    39  */
    40  
    41  // File generated by ranges2go DO NOT EDIT
    42  
    43  package cloudcidrs
    44  
    45  import (
    46  	"net/netip"
    47  )
    48  
    49  `
    50  
    51  func generateRangesGo(w io.Writer, cloudToRTP map[string]regionsToPrefixes) error {
    52  	// generate source file header
    53  	if _, err := io.WriteString(w, fileHeader); err != nil {
    54  		return err
    55  	}
    56  
    57  	// ensure iteration order is predictable for reproducible codegen
    58  	clouds := make([]string, 0, len(cloudToRTP))
    59  	for cloud := range cloudToRTP {
    60  		clouds = append(clouds, cloud)
    61  	}
    62  	sort.Strings(clouds)
    63  
    64  	// generate constants for each cloud
    65  	for _, cloud := range clouds {
    66  		if _, err := fmt.Fprintf(w, "// %s cloud\nconst %s = %q\n", cloud, cloud, cloud); err != nil {
    67  			return err
    68  		}
    69  	}
    70  
    71  	// generate main data variable
    72  	if _, err := io.WriteString(w, `
    73  // regionToRanges contains a preparsed map of cloud IPInfo to netip.Prefix
    74  var regionToRanges = map[IPInfo][]netip.Prefix{
    75  `,
    76  	); err != nil {
    77  		return err
    78  	}
    79  	for _, cloud := range clouds {
    80  		rtp := cloudToRTP[cloud]
    81  		if err := genCloud(w, cloud, rtp); err != nil {
    82  			return err
    83  		}
    84  	}
    85  	if _, err := io.WriteString(w, "}\n"); err != nil {
    86  		return err
    87  	}
    88  
    89  	return nil
    90  }
    91  
    92  func genCloud(w io.Writer, cloud string, rtp regionsToPrefixes) error {
    93  	// ensure iteration order is predictable for reproducible codegen
    94  	regions := make([]string, 0, len(rtp))
    95  	for region := range rtp {
    96  		regions = append(regions, region)
    97  	}
    98  	sort.Strings(regions)
    99  	for _, region := range regions {
   100  		prefixes := rtp[region]
   101  		if _, err := fmt.Fprintf(w, "\t{Cloud: %s, Region: %q}: {\n", cloud, region); err != nil {
   102  			return err
   103  		}
   104  		for _, prefix := range prefixes {
   105  			addr := prefix.Addr()
   106  			bits := prefix.Bits()
   107  			// Using netip.*From avoids additional runtime allocation.
   108  			//
   109  			// It also means we don't need error checking / parsing cannot fail
   110  			// at runtime, we've already parsed these and re-emitted them
   111  			// as pre-computed IP address / bit mask values.
   112  			if addr.Is4() {
   113  				b := addr.As4()
   114  				if _, err := fmt.Fprintf(w,
   115  					"\t\tnetip.PrefixFrom(netip.AddrFrom4([4]byte{%d, %d, %d, %d}), %d),\n",
   116  					b[0], b[1], b[2], b[3], bits,
   117  				); err != nil {
   118  					return err
   119  				}
   120  			} else {
   121  				b := addr.As16()
   122  				if _, err := fmt.Fprintf(w,
   123  					"\t\tnetip.PrefixFrom(netip.AddrFrom16([16]byte{%d, %d, %d, %d, %d, %d, %d, %d, %d, %d, %d, %d, %d, %d, %d, %d}), %d),\n",
   124  					b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7], b[8], b[9], b[10], b[11], b[12], b[13], b[14], b[15], bits,
   125  				); err != nil {
   126  					return err
   127  				}
   128  			}
   129  		}
   130  		if _, err := io.WriteString(w, "\t},\n"); err != nil {
   131  			return err
   132  		}
   133  	}
   134  	return nil
   135  }