├── .dockerignore ├── .gitignore ├── Cargo.lock ├── Cargo.toml ├── Dockerfile ├── LICENSE-APACHE.txt ├── LICENSE-MIT.txt ├── Makefile ├── README.md └── src └── main.rs /.dockerignore: -------------------------------------------------------------------------------- 1 | target/ 2 | **/*.rs.bk 3 | Makefile 4 | README* 5 | LICENSE* 6 | .git/ 7 | .gitignore -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | /target 2 | **/*.rs.bk 3 | -------------------------------------------------------------------------------- /Cargo.lock: -------------------------------------------------------------------------------- 1 | # This file is automatically @generated by Cargo. 2 | # It is not intended for manual editing. 3 | [[package]] 4 | name = "aho-corasick" 5 | version = "0.7.6" 6 | source = "registry+https://github.com/rust-lang/crates.io-index" 7 | dependencies = [ 8 | "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)", 9 | ] 10 | 11 | [[package]] 12 | name = "envsub" 13 | version = "0.1.4-pre" 14 | dependencies = [ 15 | "getopts 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)", 16 | "regex 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)", 17 | ] 18 | 19 | [[package]] 20 | name = "getopts" 21 | version = "0.2.21" 22 | source = "registry+https://github.com/rust-lang/crates.io-index" 23 | dependencies = [ 24 | "unicode-width 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)", 25 | ] 26 | 27 | [[package]] 28 | name = "lazy_static" 29 | version = "1.4.0" 30 | source = "registry+https://github.com/rust-lang/crates.io-index" 31 | 32 | [[package]] 33 | name = "memchr" 34 | version = "2.2.1" 35 | source = "registry+https://github.com/rust-lang/crates.io-index" 36 | 37 | [[package]] 38 | name = "regex" 39 | version = "1.2.1" 40 | source = "registry+https://github.com/rust-lang/crates.io-index" 41 | 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(registry+https://github.com/rust-lang/crates.io-index)" = "58fb5e95d83b38284460a5fda7d6470aa0b8844d283a0b614b8535e880800d2d" 68 | "checksum getopts 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)" = "14dbbfd5c71d70241ecf9e6f13737f7b5ce823821063188d7e46c41d371eebd5" 69 | "checksum lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646" 70 | "checksum memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88579771288728879b57485cc7d6b07d648c9f0141eb955f8ab7f9d45394468e" 71 | "checksum regex 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88c3d9193984285d544df4a30c23a4e62ead42edf70a4452ceb76dac1ce05c26" 72 | "checksum regex-syntax 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)" = "b143cceb2ca5e56d5671988ef8b15615733e7ee16cd348e064333b251b89343f" 73 | "checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b" 74 | "checksum unicode-width 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "7007dbd421b92cc6e28410fe7362e2e0a2503394908f417b68ec8d1c364c4e20" 75 | -------------------------------------------------------------------------------- /Cargo.toml: -------------------------------------------------------------------------------- 1 | [package] 2 | name = "envsub" 3 | version = "0.1.4-pre" 4 | description = "Command line utility for substituion of environment variables" 5 | authors = ["Stephen Connolly "] 6 | edition = "2018" 7 | license = "Apache-2.0" 8 | homepage = "https://github.com/stephenc/envsub" 9 | repository = "https://github.com/stephenc/envsub" 10 | readme = "README.md" 11 | keywords = ["cli"] 12 | categories = ["command-line-utilities"] 13 | 14 | [package.metadata.release] 15 | sign-commit = true 16 | sign-tag = true 17 | dev-version-ext = "pre" 18 | tag-name = "{{version}}" 19 | 20 | [dependencies] 21 | getopts = "0.2" 22 | regex = "1" 23 | -------------------------------------------------------------------------------- /Dockerfile: -------------------------------------------------------------------------------- 1 | FROM ekidd/rust-musl-builder AS build 2 | 3 | # Add our source code. 4 | ADD --chown=rust:rust . ./ 5 | 6 | # Build our application. 7 | RUN cargo build --release 8 | 9 | FROM scratch 10 | 11 | COPY --from=build /home/rust/src/target/x86_64-unknown-linux-musl/release/envsub /bin/ 12 | 13 | ENTRYPOINT ["/bin/envsub"] 14 | -------------------------------------------------------------------------------- /LICENSE-APACHE.txt: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright {yyyy} {name of copyright owner} 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /LICENSE-MIT.txt: -------------------------------------------------------------------------------- 1 | Copyright (c) 2019 Stephen Connolly 2 | 3 | Permission is hereby granted, free of charge, to any person obtaining a copy 4 | of this software and associated documentation files (the "Software"), to deal 5 | in the Software without restriction, including without limitation the rights 6 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 7 | copies of the Software, and to permit persons to whom the Software is 8 | furnished to do so, subject to the following conditions: 9 | 10 | The above copyright notice and this permission notice shall be included in all 11 | copies or substantial portions of the Software. 12 | 13 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 14 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 15 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 16 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 17 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 18 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 19 | SOFTWARE. 20 | -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | IMG_ID=$(shell dd if=/dev/urandom bs=1k count=1 2> /dev/null | LC_CTYPE=C tr -cd "a-z0-9" | cut -c 1-22) 2 | 3 | 4 | build: target/x86_64-unknown-linux-musl/release/envsub.gpg target/x86_64-unknown-linux-musl/release/envsub.sha256 5 | 6 | .PHONY: publish 7 | publish: 8 | docker build --tag stephenc/envsub:latest . 9 | docker push stephenc/envsub:latest 10 | 11 | .PHONY: clean 12 | clean: 13 | cargo clean 14 | 15 | target/x86_64-unknown-linux-musl/release/envsub: Cargo.lock Cargo.toml src/main.rs 16 | mkdir -p target/x86_64-unknown-linux-musl/release 17 | docker build --tag envsub:latest . 18 | docker run --rm envsub:latest cat /bin/envsub \ 19 | > target/x86_64-unknown-linux-musl/release/envsub 20 | 21 | %.gpg: % 22 | gpg -a --output $@ --detach-sig $< 23 | 24 | %.sha256: % 25 | cat $< | openssl dgst -sha256 > $@ 26 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # envsub 2 | 3 | ``` 4 | $ envsub [options] 5 | ``` 6 | 7 | The `envsub` program substitutes the values of environment variables. 8 | Unlike [envsubst](https://www.gnu.org/software/gettext/manual/html_node/envsubst-Invocation.html), which only supports `${NAME}` style substitution, the `envsub` program also supports `${NAME-default}` and `${NAME:-default}` style substitution. 9 | 10 | The program pipes stdin to stdout one line at a time applying the required substitutions. 11 | 12 | ## Command line options 13 | 14 | `-h`, `--help`:: Displays the help details of the command and exit. 15 | 16 | `-p`, `--prefix`:: Allows configuring an alternative prefix for substitution patterns if the default of `${` would cause conflicts. 17 | 18 | `-s`, `--suffix`:: Allows configuring an alternative suffix for substitution patterns if the default of `}` would cause conflicts. 19 | 20 | *NOTE:* If your suffix starts with `:` or `-` you will not have a good time as this will conflict with the default value separator that is internal to the pattern. 21 | 22 | `-g`, `--greedy-defaults`:: Enables greedy replacement of unmatched default values. With this option if you have `${FOO}` and there is no corresponding variable `FOO` then that will remain untouched but `${FOO:-BAR}` or `${FOO-BAR}` will be replaced as `BAR` whereas without this option they would remain untouched. 23 | 24 | `-v`, `--var`:: Only replace the named variable. _Can be specified multiple times_ if you want to replace multiple variables. If not specified then all variables from the environment can be substituted. 25 | 26 | `-V`, `--version`:: Display the program version and exit. 27 | 28 | ## Examples 29 | 30 | TIP: When running `envsub` without the `-v` argument then only patterns that have environment variables will be searched for, so the `${NAME-default}` form will never be replaced if `NAME` is not defined. 31 | 32 | Basic usage: 33 | ``` 34 | $ (echo 'FOO=${FOO} or ${FOO-unset} or ${FOO:-empty}') | (unset FOO && envsub) 35 | FOO=${FOO} or ${FOO-unset} or ${FOO:-empty} 36 | $ (echo 'FOO=${FOO} or ${FOO-unset} or ${FOO:-empty}') | (unset FOO && envsub -v FOO) 37 | FOO=${FOO} or unset or empty 38 | $ (echo 'FOO=${FOO} or ${FOO-unset} or ${FOO:-empty}') | (FOO= envsub) 39 | FOO= or or empty 40 | $ (echo 'FOO=${FOO} or ${FOO-unset} or ${FOO:-empty}') | (FOO= envsub -v BAR) 41 | FOO=${FOO} or ${FOO-unset} or ${FOO:-empty} 42 | $ (echo 'FOO=${FOO} or ${FOO-unset} or ${FOO:-empty}') | (FOO=123 envsub) 43 | FOO=123 or 123 or 123 44 | ``` 45 | 46 | Custom prefixes and suffixes: 47 | ``` 48 | $ (echo 'FOO=%FOO:-empty%') | (FOO= envsub -p '%' -s '%') 49 | FOO=empty 50 | ``` 51 | -------------------------------------------------------------------------------- /src/main.rs: -------------------------------------------------------------------------------- 1 | // Copyright 2019 Stephen Connolly. 2 | // 3 | // Licensed under the Apache License, Version 2.0 or the MIT license 5 | // , at your 6 | // option. This file may not be copied, modified, or distributed 7 | // except according to those terms. 8 | 9 | extern crate core; 10 | extern crate getopts; 11 | extern crate regex; 12 | 13 | use getopts::Options; 14 | use regex::Captures; 15 | use regex::Regex; 16 | 17 | use core::borrow::Borrow; 18 | use std::collections::HashMap; 19 | use std::env; 20 | use std::io; 21 | use std::io::BufRead; 22 | use std::io::LineWriter; 23 | use std::io::Write; 24 | 25 | fn create_options() -> Options { 26 | let mut opts = Options::new(); 27 | opts.optflag("h", "help", "print this help menu and exit"); 28 | opts.optflag("V", "version", "print the version and exit"); 29 | opts.optflag( 30 | "g", 31 | "greedy-defaults", 32 | "allow expansion of undefined variable defaults", 33 | ); 34 | opts.optmulti( 35 | "v", 36 | "variable", 37 | "restrict expansion to named variables only", 38 | "VAR", 39 | ) 40 | .optopt( 41 | "p", 42 | "prefix", 43 | "set the expansion prefix marker (default: ${)", 44 | "PREFIX", 45 | ) 46 | .optopt( 47 | "s", 48 | "suffix", 49 | "set the expansion suffix marker (default: })", 50 | "PREFIX", 51 | ); 52 | opts 53 | } 54 | 55 | fn print_usage(program: &str, opts: Options) { 56 | let brief = format!("Usage: {} [options]", program); 57 | println!("{}", opts.usage(&brief)); 58 | println!(); 59 | println!("Rewrites input to output expanding environment variables"); 60 | println!(); 61 | println!("NOTE: Only ${{ENV_VAR}} and ${{ENV_VAR-default value}} are supported"); 62 | println!(" (and you are on your own if your default value needs to include"); 63 | println!(" a }} character)"); 64 | } 65 | 66 | fn main() { 67 | const VERSION: &'static str = env!("CARGO_PKG_VERSION"); 68 | let args: Vec = env::args().collect(); 69 | let program = args[0].clone(); 70 | 71 | let opts = create_options(); 72 | let matches = match opts.parse(&args[1..]) { 73 | Ok(m) => m, 74 | Err(f) => panic!(f.to_string()), 75 | }; 76 | if matches.opt_present("h") { 77 | print_usage(&program, opts); 78 | return; 79 | } 80 | if matches.opt_present("V") { 81 | println!("{}", VERSION); 82 | return; 83 | } 84 | let prefix = match matches.opt_str("p") { 85 | Some(v) => v, 86 | None => "${".to_string(), 87 | }; 88 | let suffix = match matches.opt_str("s") { 89 | Some(v) => v, 90 | None => "}".to_string(), 91 | }; 92 | let greedy = match matches.opt_present("g") { 93 | true => Some( 94 | Regex::new( 95 | format!( 96 | r#"{}[a-zA-Z_][a-zA-Z0-9_]*:?-(.*?){}"#, 97 | regex::escape(prefix.clone().as_str()), 98 | regex::escape(suffix.clone().as_str()) 99 | ) 100 | .as_str(), 101 | ) 102 | .unwrap(), 103 | ), 104 | false => None, 105 | }; 106 | let vars = match matches.opt_present("v") { 107 | true => { 108 | let mut vars = HashMap::new(); 109 | for var_name in matches.opt_strs("v") { 110 | vars.insert( 111 | var_name.clone(), 112 | match env::var(var_name.clone()) { 113 | Ok(v) => ( 114 | Regex::new( 115 | format!( 116 | r#"{}{}((:?-)(.*?))??{}"#, 117 | regex::escape(prefix.clone().as_str()), 118 | regex::escape(var_name.as_str()), 119 | regex::escape(suffix.clone().as_str()) 120 | ) 121 | .as_str(), 122 | ) 123 | .unwrap(), 124 | Some(v), 125 | ), 126 | Err(_) => ( 127 | Regex::new( 128 | format!( 129 | r#"{}{}((:?-)(.*?))??{}"#, 130 | regex::escape(prefix.clone().as_str()), 131 | regex::escape(var_name.as_str()), 132 | regex::escape(suffix.clone().as_str()) 133 | ) 134 | .as_str(), 135 | ) 136 | .unwrap(), 137 | None, 138 | ), 139 | }, 140 | ); 141 | } 142 | vars 143 | } 144 | false => { 145 | let mut vars = HashMap::new(); 146 | for (key, value) in env::vars() { 147 | vars.insert( 148 | key.clone(), 149 | ( 150 | Regex::new( 151 | format!( 152 | r#"{}{}((:?-)(.*?))??{}"#, 153 | regex::escape(prefix.clone().as_str()), 154 | regex::escape(key.as_str()), 155 | regex::escape(suffix.clone().as_str()) 156 | ) 157 | .as_str(), 158 | ) 159 | .unwrap(), 160 | Some(value), 161 | ), 162 | ); 163 | } 164 | vars 165 | } 166 | }; 167 | 168 | let reader = io::stdin(); 169 | let mut writer = LineWriter::new(io::stdout()); 170 | 171 | for line in reader.lock().lines() { 172 | let mut out = line.unwrap(); 173 | for (_, (regex, value)) in &vars { 174 | let val = &value.clone(); 175 | out = regex 176 | .replace_all(out.as_str(), |caps: &Captures| -> String { 177 | match caps.get(2) { 178 | Some(mat) => match mat.as_str() { 179 | ":-" => match val.borrow() { 180 | Some(v) => { 181 | if v.is_empty() { 182 | caps.get(3).map_or("", |m| m.as_str()) 183 | } else { 184 | v.as_str() 185 | } 186 | } 187 | None => caps.get(3).map_or("", |m| m.as_str()), 188 | }, 189 | _ => match val.borrow() { 190 | Some(v) => v.as_str(), 191 | None => caps.get(3).map_or("", |m| m.as_str()), 192 | }, 193 | }, 194 | None => match val.borrow() { 195 | Some(v) => v.as_str(), 196 | None => caps.get(0).unwrap().as_str(), 197 | }, 198 | } 199 | .to_string() 200 | }) 201 | .to_string(); 202 | } 203 | out = match greedy.clone() { 204 | Some(regex) => regex 205 | .replace_all(out.as_str(), |caps: &Captures| -> String { 206 | caps.get(1) 207 | .clone() 208 | .map_or("", |m| m.as_str()) 209 | .clone() 210 | .to_string() 211 | }) 212 | .to_string(), 213 | None => out, 214 | }; 215 | writer.write(out.as_bytes()).unwrap(); 216 | writer.write("\n".as_bytes()).unwrap(); 217 | writer.flush().unwrap(); 218 | } 219 | } 220 | --------------------------------------------------------------------------------